Nelumbo nucifera

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Propagation

Nucifera can be propagated by seed or rhizome.[1][2] Specific cultivars are bred for seed, rhizome, or flower production.[3]

Natural cultivation has a seed-set rate of 50-80%, though other authors have reported up to 90%. Some cultivars are more self-incompatible than others.[4]

Captured Brycinus lateralis (striped robber fish) often have caerulea seeds in their digestive tract. These seeds have about a 12% germination rate (no comparison to undigested seeds).[5]

Germination

Freezing does not affect seed germination in N. lutea.[6]

Seeds remain viable for centuries or millennia, although they sometimes lack vigor or are more fragile than their young counterparts. This is likely due to extended exposure to radiation that also leads to overt morphological differences in old specimens.[7][8]

Seeds with pericarp in tact will not germinate in water even after two years.[9][10]

Propagule wall.[11]

Breaking the seed coat in a vise, and abrading with a file or sandpaper results in immediate water absorption and swelling.[9]

Treatment with an organic solvent to remove the waxy impermeable layer could potentially allow water absorption. Acetone-washed seeds will swell but not germinate due to the death of the embryo. Ether-washed seeds will germinate. Alcohol, chloroform, and xylol failed to soften the seeds.[10]

Soaking in Schweitzer’s reagent for 75-200 hours also results in germination and fully functioning embryos. Three hundred hours destroy the embryos.[12]

Commercial seed producers can weaken the seed coat by soaking it in concentrated sulfuric acid for 5 hours, followed by rinsing and drying. Thus the seed will readily germinate upon soaking without additional treatment by the customer.[9]

Three hours in concentrated sulfuric acid followed by manual removal of the seed coat[13], 160 min in 80% sulfuric acid[14], and removal of the seed coat by saw[7] has also been used.

High light intensities (30,000 lux) improve adventitious rooting.[15]

Sterile seed germination is exceptionally difficult. Nearly all seeds subjected to traditional and extensive washing, bleaching, and ethanol disinfection procedures failed to give sterile cultures despite excellent germination.[16] This could be due to endophytic bacteria present inside the seed, having been identified as Pseudomonas spp. by the authors. Though, the pocketed seed coat of nucifera could be protecting these microorganisms from chemical disinfectants due to their water-repelling capabilities.

The seeds of nucifera contain fully formed chlorophylls. Upon germination in light, the shoots begin photosynthesizing and generating oxygen, a huge advantage for the anaerobic conditions of submerged mud in stagnant ponds.[17]

Seeds are relatively insensitive to nutrients at the time of germination. Dilution of miracle grow at 100x (stock solution 50.6g/L; 100x dilution: 0.5g/L) was used for all stages of growth in soil/clay sediment.[8]

In N. lutea, floating seeds have poorly developed embryos or damage that results in no or very little germination.[18] In nucifera, floating seeds have slightly worse germination than sinking seeds, but not by much.[14]

LD50 of nucifera without a seed carp exposed to 100°C is 14.5 hours.[19] LD50 at 90°C is approximately 24 hours.[20]

Seed propagation is highly heterogeneous.[3]

Seedlings are especially sensitive to overfertilization.[3]

Some seeds that were never fully dried retain the ability to absorb moisture during imbibition and germinate.[21]

Sanding the base (funicule), “germ pore” (stigma scar), or the dorsal side of the nucifera seed has an identical germination rate at 15 days. Sanding the base slightly accelerates germination.[14]

Up to four leaves are expected from each seed.[12]

Seed germination is not particularly affected by water temperature.[14]

The 0.2cc of air contained in a pocket inside the seed is necessary and sufficient for germination.[22]

Vegetative

Three-node stolon cuttings are the industry standard propagation method. Two node cuttings are sufficient for propagation, however. Single node cuttings have moderately reduced growth. The largest differences occur in flower production with an increased time to flowering (89 vs. 63 days for triple-node) and the total number of flowers (1.4 vs 2.9 for triple-node).[23]

In-Vitro

Cultivation

The critical photoperiod for rhizome enlargement is approximately 12-13 hours. Once rhizome enlargement is triggered, leaf proliferation stops.[13]

Five months after planting there was a very decided difference, definitely showing that the soil type is probably the most important factor in the development of Nelumbo.[12]

Organic soils are preferable to mineral soils.[12]

Nucifera can be cultivated commercially in artificial ponds made with concrete. These tanks have a 45cm deep clay soil stratum and a water level of 1-1.5m. Each plant requires fertilization and about 4m^2^ of space though a minimum of 2m^2^ has been used.[1][13]

Leaves must not be submerged in water. They will suffocate and die.[24][1] Water may be added slowly to growing containers to maintain the leaves above the water line.

Nucifera tolerates a wide range of pH (4.5-9) but grows best at 5.5-8.0.[1][3] Low pH (4.5) tends to favor shoot growth but interferes with proper rhizome energy storage.[12]

Nucifera can survive prolonged freezing so long as its soil bed remains unfrozen.[8]

N. lutea leaves will drown after two weeks, but they can tolerate a month of complete dewatering.[25][24] Leaves that have not unfurled can elongate to compensate for flooding, but older leaves cannot.[24][26]

This may not be leaf drowning per se, but a rupture of the diaphragmatic nets that prevent water from entering the gas canals of the nucifera rhizome.[27]

Young seedlings are rapidly affected by environmental disturbance. Adverse symptoms of physical handling, nutrient toxicity, dehydration, etc. were visible very quickly.[8]

First-year growth is typically prostrate with floating leaves. In the following years, the growth of the leaves above the water’s surface indicates healthy plants.[8]

First-year seedlings of N. lutea are unlikely to flower.[18] First-year rhizome propagated plants will likely flower in the first season.[12]

N. lutea rhizomes can be extracted and stored in moistened sphagnum peat in the cold (4-8°C) for the winter season if the submerged soil in outdoor containers is likely to freeze.[18]

Long day length promotes vegetative growth and a short day length promotes rhizome enlargement and dormancy. Increased temperatures generally accelerate the production of either.[13]

The switch from rhizome elongation to rhizome enlargement is controlled by phytochrome absorption of red/far-red light. Two hours of nighttime lighting by red/yellow/white light is sufficient to deter rhizome enlargement and dormancy even when the day length is below the 12-13 threshold. The effect is reversed (plant switches to dormancy) when immediately followed by far-red illumination.[28]

Shorter periods of light break (5-15 min) can inhibit dormancy if given at the appropriate time after initiation of the dark period.[29]

Increasing the day length increases the flowering percentage but delays flowering.[30]

Nelumbo makes great phytoremediation plants due to their ability to transport air to the hypoxic root system and bioaccumulation of heavy metals.[31]

Floating leaves are produced first and continue to be born throughout the growing season. Emergent leaves are produced somewhat later but constitute approximately 75% of the total leaf area during peak leaf production.[32]

Emergent leaves survive approximately three times longer than floating leaves.[32]

Adventitious root formation is regulated, in part, by ethylene signaling.[33]

Harvest

Yield

Soilless

Soil

Amending local soil with 32% (v/v; 5-10 mm sieved pieces) pine biochar (the highest proportion tested) significantly increased the height, diameter, and area of emergent leaves. Total fresh and dry mass of both leaves and rhizomes were similarly increased in 32% char-soil, with a clear dose-dependent relationship. Cadmium accumulation was significantly, dose-dependently reduced by biochar addition.[34]

Fertilization

Unlike land plants, copper fertilization is probably less important to water-dwelling plants. Many of the copper-based enzyme systems in plants exposed to hypoxic deep water conditions are replaced by iron-based systems presumably because of the poor solubility of nonoxidated copper compounds. Nucifera has both systems and might switch between them based on the environmental availability of metals.[17]

However, genetic studies have noted extensive copper-based enzyme systems adapted for phosphate starvation at the roots.[35]

The clay soil is enriched by incorporating well-decomposed cattle dung manure @ 5 kg/m2, neem cake @100 gm/m2 , di-ammonium phosphate {DAP) @ 25 gm/m2, single superphosphate @ 50 gm/m2 and muriate of potash @ 25 gm/m2 as a basal dose at least 15 days prior to the planting (February - March).[1]

Fertilization must be balanced by the growth of competitive algae growth.[8]

Extended-release fertilizer tablets at 5g/l can be applied to N. lutea after new leaves emerge in the spring (Osmocote Exact tablets; 8-9 month release).[18]

Fertilizer rates should be scaled with media volume due to its buffering and ion exchange capacity. Similarly, the same fertilizer added to a high media:water container would result in higher EC by dilution.[36]

EC should be maintained between 0.15 and 1.0 mS/cm with the ideal close to 0.5 mS/cm or lower.[3] Some authors report using an ideal EC as high as 3.1 mS/cm.[37]

Five percent Hoagland solution produces normal morphology but no indication of optimization was given.[38]

Excessive fertilization is dangerous and can kill nucifera quickly.[3]

In a study of nitrogen fertilization in the form of urea, 45g/m2 was the optimal application rate.[39]

Nucifera are not tolerant to excessive nutrient concentrations. Nutrient toxicity is notable at about 25x dilution of Miracle Grow (50.6 g/L stock solution). Less damage appears at 50x and 75x dilution. Pale green or yellow leaves occur at greater than 100x dilution. [8]

Wilting and brown or yellow spots result from a pH of 4.5. Securing the leaves above the water’s surface fixed this issue.[12] I am guessing this is the result of some transpiration issue coupled with a calcium deficiency.

Pests

Aphids are a major pest. An appropriate wetting agent needs to be added to any pesticide due to the water-beading effects of lotus leaves.[1]

Algae thrive in the same conditions as nucifera. Adequate aeration can inhibit algae growth. Large accumulations can be removed by skimming if necessary.[8]

Ecology

Morphology

Extensive description.[40]

Karyotype 2n=16.[41]

Roots

All lotus roots (N. lutea) are adventitious.[25]

Rhizomes

The rhizomes [of N. lutea] are of two types: slender (6 mm. to 8 mm.) and large (8 mm. to 20 mm.). The slender (white) ones usually were found within the top four inches of the soil, whereas the larger rhizomes (white or pink) were established to depths of 18 inches.[25]

Stem

The leaf stalk just below the leaves is responsible for the majority of air exchange. Older plants can survive in deeper water primarily because of the increased gas exchange by lifted leaves above the water’s surface. Improper pruning of the leaf stalk can suffocate and kill the rhizome below.[8]

Each leaf and stalk carry 10+-5 ml/min of air to the buried rhizome.[31]

Leaves

Two leaf types exist: floating and emergent.

Some leaves transition from floating to emergent early in the growing season. Their petioles are relatively weak contributing to their reduced lifetime.[32]

Emergent leaves are more stout and are about 1.4 times heavier (dry weight basis) than their floating counterparts.[32]

Inflorescence

Long-day plant with a photoperiod of ~13 hours.[8]

One flower bud per node.[42]

Protogynous flowers.[4]

Flowers come in white and red for nucifera and yellow for N. lutea. Crosses exist between the species that give mixed colors and even spotted versions.[43] Blue does not exist![43][44][45][46]

Flower color is not exclusively genetic. At least some amount of control is exerted epigenetically.[43]

Flowers can thermoregulate.[47]

Seeds

Seeds are ovoid approximately 15mm long by 11mm wide. The small indentation at one end is the place of attachment. The protuberance at the opposite end was the original stigma.[10]

Phytochemistry

Nearly a 50% increase in alkaloid content of nucifera leaves in response to mechanical wounding. This may be due to the increased concentration of alkaloids in the leaking sap and not specifically a wounding response.[48]

The highest concentration of alkaloids is in the leaves and plumules. This is likely why the plumules are commonly removed prior to ingestion due to the bitter taste of these alkaloids. Two “seed producing” cultivars (“Super No 1” and “Super No 2”) have the highest alkaloid production of the 46 cultivars tested–more than ten times higher than the lowest.[48]

Nucifera stamen products are sometimes adulterated or completely substituted with Nymphaea lotus due to N. lotus’ lower cost.[49]

[48]

Infraspecific Variation

Biosynthesis

Distribution

Timecourse

Improvement

Identification

Inheritance

Methods

History & Society

Work Log

29 Jan 2023

Checked on the rhizomes in storage. Only one has tried sprouting. I removed some of the surface peat moss and everything appears in good order. No mold. No rodent bites.

18 Oct 2022

Harvested the rhizomes and chopped them up for storage.

25 Aug 2022

The Nelumbo sp. has grown to this size in only 3 months from seed (direct-sown trial 3).

22 Aug 2022

Buried 4 capsules of each ammonium sulfate (~3.2g) and triple super phosphate (~5g) to the nucifera tank.

09 Aug 2022

These leaves are getting big.

05 Jul 2022

Some new leaves have arrived. Also, the algae have bloomed.

27 Jun 2022

Transfer complete and established.

26 Jun 2022

This tank’s not big enough for both of them. I’m going to transfer the Nelumbo to a deeper container by itself. Using a standard 1:2 sand:topsoil mix.

Before the transfer.

Some roots close up.

Abaxial leaf surface.

15 Jun 2022

Emergent leaf produced.

30 May 2022

A second leaf has arrived and the first leaf has fully opened.

20 May 2022

The direct-sown seed (trial 3) has produced a leaf.

14 May 2022

Planted a scarified seed directly in the large tank (trial 3).

21 Mar 2022

Ooof. Seed 1 is not doing well.

At least seed 2 is growing quickly. The roots are strong and a shoot has emerged (3 petioles).

06 Mar 2022

Trial 2 is proceeding well. The first leaf has hit the water’s surface. I exchange the water every couple of days as it becomes cloudy.

27 Feb 2022

I have removed some dead shoots from seed 1.

Shoot has emerged on trial 2.

23 Feb 2022

Seed 2 has now split. I moved it to a larger tank under grow light.

Notice how the split occurred on the side where the shoot will emerge (funicule) despite the sanding on the opposite side (micropyle).

17 Feb 2022

I wanted to demonstrate how to sand the seed coat of Nelumbo, so I might as well germinate the seed. No sterilization this time. Just sanded and straight into tap water in the incubator.

26 Jan 2022

The new tank is working well. A leaf has emerged.

24 Jan 2022

Now that the new tank has been decanted at least 5 times, it is settling quickly with each new water addition. It is finally time to transfer the seedling.

I ended up adding about an equal weight of clay to the coir:charcoal mix. I just kept adding it until I felt like the mix was sufficiently thick.

The seedling was transferred and the tank was moved to the nymphaea tank. This allows me to share the aquarium heater and grow light.

21 Jan 2022

Root and shoot progress.

19 Jan 2022

The new tank has been settled.

18 Jan 2022

Finally got the kaolin.

• 91g coir (~ 1L)
• 206g char (~1.1L)
• 100g EPK kaolin
• +400g kaolin later
• +10g bentonite (brewing grade in 200ml water)

Oh right… coir and char float. Heating double-boiler style to help the porous substrates absorb water and sink.

Coir releases tannins over time. I may need multiple washes.

17 Jan 2022

Another example of the extensive gas transfer system to the roots of nucifera.

13 Jan 2022

I think I will use real ceramics clay instead of whatever happens to be in cat litter. Kaolin is a common clay in Asia. A 50-pound bag of EPK Kaolin is about $20 from my local pottery supply store.

Southeast Asia and India specifically have a high proportion of kaolinite clays with moderate amounts of smectite, hematite, illite, and feldspar.[50]

12 Jan 2022

Working on growing media composition. Peat layered with stone was shown to work in the literature, but I would like to avoid peat for environmental reasons. Coco coir might be a suitable replacement. I want to incorporate biochar. As always, I like to avoid soil for cleanliness and reproducibility reasons.

I’m thinking of using clay cat litter, homemade hardwood biochar, and coir. Perhaps with a layer of sand on top to minimize media disturbances. Biochar and coir will have an excess of carbon for removing any oxygen to minimize competition. Clay will help anchor the plant and fill in any gas-permeable gaps.

I made some biochar by open-pit burning some sticks from my yard. Mostly oak branches but all hardwood. The char was soaked in water overnight. The unburned pieces were removed manually. Char was sieved through a 1/4-inch screen. The smallest particles (<1mm) were removed by a second sieve and by repeated rinsing (5-6 volumes in total of tap water were used).

The final char weighed 692 g damp and 204 g dry with an approximate volume of a little over one liter.

Bentonite/Fuller’s Earth-based clay cat litter (Walmart cheap stuff) was ground in a blender. After drying, about 400g (625 g before drying) with a volume of approximately half of a liter was collected. I processed this batch of cat litter years ago for rocket nozzles but didn’t use it all. The finer grain will allow for easy mixing, but not easy replication.

The container I intend to use is a glass cylinder 19 cm tall and 19 cm in diameter (1-gallon Anchor Hocking Heritage Hill Clear Glass Jar with Lid). The maximum volume of water and soil should be about 3 liters and be about 15 cm tall. One-third of that volume will be media.

11 Jan 2022

A close-up of the second seed used for dissection.

And without the seed coat.

07 Jan 2022

This shoot keeps extending.

06 Jan 2022

More roots and shoots develop.

05 Jan 2022

The first shoot is starting to recover. The leaf has turned up toward the air and is now poking above the water’s surface. The second and third shoots are still growing. Roots continue to advance but have darkened slightly.

This process of extending beyond the water’s surface and then laying down might be the natural thing that new shoots do.[51]

The lighting is a little low. 1500-2000 lux. It should be 20,000 or even 30,000. My measurements correspond to the delay in root formation seen in the literature.[15]

pH is ~6.4 (Hydrion pH paper)

Ooof. My tap water is a bit on the high side of TDS.

The nucifera doesn’t seem to mind, though.

04 Jan 2022

I’m having terrible luck with heaters. The vertical stalk was a little droopy this afternoon.

I thought it was nothing. I checked the EC: ~0.8. I checked the water temperature: 34°C!!

So I quickly replaced some of the water with cold tap water to cool it below 30°C. Then I replaced the heater with a preset Tetra fish tank heater. It is set at 25°C: Lower than I wanted, but acceptable.

The second shoot seems to be unaffected and a third has sprouted. I hope it is still ok.

The thermostat must have gotten stuck on the heater or something. Figures.

03 Jan 2022

Waiting for the emergent leaf to open.

Now that I have transferred the seeds to the new germination chamber, the old chamber can be repurposed.

This should be the final variation on the timelapse and probably the nucifera’s home for a while.

An example shot:

I did get a nice shot of the emerging roots and a second shoot during the transfer.

I added a water heater to keep the temperature 28-30°C.

During the water refill, I added a couple of pinches of Masterblend tomato fertilizer (from my hydroponics stores). So maybe 1 gram in 10 liters of water. A check with my cheap meter shows 340ppm or about 0.68 ms/cm. That’s a little higher than I wanted but in the acceptable range for nucifera.

Gas transfer to the roots has already begun.

02 Jan 2022

Timelapse is progressing as well as can be expected. Nucifera grows very fast, so I have to constantly adjust the camera.

I finally let the nucifera rest for the night. I have kept the light on constantly until now. That’s 9 days of constant light.

I think a root has sprouted from the seed, though it might be another leaf for some reason.

24 Dec 2021

Finally have the first seed timelapse set up. Just in time too, since the shoot has begun to appear.

I was worried for a bit since the seed was blackened severely by the sulfuric acid treatment. I thought the cotyledons might have been damaged.

Exchanged the water. It was taking on some color.

21 Dec 2021

Started one seed of “Blue Lotus” (an obvious fake). The seed matches that of other Nelumbo, but I guess we will see what comes out.

Soaked for 4 hours in ~5ml of 96% sulfuric acid (drain cleaner source). Concentrated sulfuric acid has a density of about 1.8, so the seed floated on the surface. A bit of agitation was performed every hour or so.

Notes

Bibliography

1. Goel, Anil and Sharma, S.C. and Sharga, A.N., The Conservation of the Diversity of Nelumbo (Lotus) at the National Botanical Research Institute, Lucknow, India, Botanic Gardens Conservation News, vol. 3, no. 6, pp. 52--54, 2001. url: https://www.jstor.org/stable/24798441.
2. Katori, Masato and Nomura, Kazunari and Yoneda, Kazuo, Propagation of Flowering Lotus (Nelumbo Nucifera Gaertn) by Rhizome Straps, without Enlarged Rhizomes, Japanese Journal of Tropical Agriculture, vol. 46, no. 3, pp. 195--197, 2002. doi: 10.11248/jsta1957.46.195.
3. McGrath, Colleen, Fertilizers Affect Water and Substrate EC, pH, and Nutritional Concentrations for Nelumbo Production, May 2012. url: https://etd.auburn.edu//handle/10415/3088. Abstract
   Sacred Lotus (Nelumbo nucifera Gaertn.) is an aquatic, herbaceous perennial considered to be one of the most valuable plants in the world. Each part of lotus is consumed throughout Asia for food or used for medicinal purposes. Effects of fertilizer type (conventional, organic, or no fertilizer), fertility rate, and water depth on water and substrate electrical conductivity (EC), pH, nitrate-nitrogen, and ammonium-nitrogen concentration were evaluated in greenhouse and outdoor studies to determine effect on potential lotus growth. All fertilizers influenced water and substrate EC, pH, and nutritional concentration. According to substrate analysis, EC rates were above recommended levels. Both organic treatments resulted in high sodium levels and the organic Nature Safe treatment resulted in higher levels of most macronutrients by termination of all studies. Results indicated increased water volumes led to reduced nutrient concentration and availability. All measured parameters decreased with increased water depths due to greater water volume and dilution factors and researchers determined a water depth of 15.2 cm (6 in) resulted in satisfactory EC levels for lotus production. There would be no additional benefit in maintaining shallower or greater depths. EC is a strong factor influencing lotus growth and with shallower depths, EC could rise close to toxic levels as was revealed in the organic Medina Growin’ Green treatment. Toxic EC level of 1.0 mS•cm-1 was surpassed with increasing rates to 1.3 kg•m-3N among both conventional and organic treatments. Under greenhouse conditions with moderate temperatures, researchers determined 0.6 kg•m-3N was a potentially acceptable rate to target for the fertilizers tested for outdoor production. The rate resulted in toxic levels of soluble salts for some fertilizers and required removal and replacement of plants, substrate, and fertilizer; adjusting the rate to 0.4 kg•m-3N. A rate of 0.44 kg•m-3N resulted in acceptable EC levels for all fertilizers trialed and tested. More research needs to be conducted to determine the interactions, cause and effect of the many variables on specific fertilizer nutrient release to target a satisfactory level to maximize growth while minimizing any potential crop damage due to an increase in EC to toxic levels.
4. Khatfan, Akhom and Li, Zuo and Chen, Long-Qing and Riablershirun, Nopadol and Sathornviriyapong, Vithaya and Juntawong, Niran, Pollen Viability, Germination, and Seed Setting of Nelumbo Nucifera, ScienceAsia, vol. 40, no. 6, pp. 384, 2014. doi: 10.2306/scienceasia1513-1874.2014.40.384.
5. Mmusi, M and Mosepele, K and {Murray-Hudson}, M and Teketay, D and Horn, M, Role of Brycinus Lateralis (Teleostei: Alestidae) in Dispersal and Germination of Nymphaea Nouchali (Angiospermae: Nymphaeaceae) Seeds on a Seasonal Floodplain of the Okavango Delta, Botswana, African Journal of Aquatic Science, vol. 41, no. 4, pp. 489--494, December 2016. doi: 10.2989/16085914.2016.1244041. Abstract
   Seed passage through the gut of vertebrates can be important for seed dispersal, but might influence seed viability. The ability of seeds to germinate after ingestion by seed-eating fish is important for the population dynamics of some plant species, and significant in the evolution of plant–fish interactions. Certain fish in the Okavango Delta, Botswana, are fruit- and seed-eaters and could act as seed dispersers. We sampled 14 fish species in 2013, finding Nymphaea nouchali var. caerulea seeds in the digestive tracts of eight, most commonly in the striped robber Brycinus lateralis. Seeds extracted from the gut of this species had an overall mean germination success of 11.7\%. This fish species might well be a legitimate seed disperser, having a positive effect on seed dispersal from parent plants in the Okavango Delta. The current study represents one of the first investigations of the likelihood of seed dispersal by fish on the African continent.
6. DeGroft, Kathleen L. and Francko, David A., Effect of Freezing on Germination of Nelumbo Lutea (Willd.) Pers. Seeds, Journal of Freshwater Ecology, vol. 11, no. 3, pp. 373--376, September 1996. doi: 10.1080/02705060.1996.9664460. Abstract
   We tested the ability of cold (4°C) and freezing (-20°C) treatments to scarify Nelumbo lutea seeds and thus enhance germination-frequency. Cold/freezing temperatures alone did not weaken seed coats enough to promote germination. Time-dependent seed germination curves and germination frequencies were statistically similar at all temperature treatments. The data suggest that freeze-thaw events in natural sediments may be insufficient to induce N. lutea germination.
7. Priestley, David A. and Posthumus, Maarten A., Extreme Longevity of Lotus Seeds from Pulantien, Nature, vol. 299, no. 5879, pp. 148--149, September 1982. doi: 10.1038/299148a0. Abstract
   In 1923 Ohga1 first brought to general scientific attention the existence of a cache of viable seeds of East Indian lotus (Nelumbo nucifera Gaertn.), contained within an ancient lakebed deposit at Pulantien in southern Manchuria. From the geological and historical evidence available, Ohga suggested a possible age in excess of 400 years1,2. Libby3 radiocarbon dated some of Ohga's material at 1040±210 years BP. This evidence of great antiquity for viable seeds has been controversial4–6. The main hindrance to the resolution of the problem has been the paucity of available Pulantien seeds following the dissipation of Ohga's original collection7. Recently we have received four Pulantien seeds, three of which were viable, albeit lacking in vigour. The lipids of the unimbibed seeds were examined and found to be still highly polyunsaturated, suggesting that they had undergone little atmospheric autoxidation. Radiocarbon dating of one of the viable seeds suggested a probable age of about 466 years at the time of germination. This is the oldest viable seed for which an age has been directly determined.
8. {Shen-Miller}, J. and Schopf, J. William and Harbottle, Garman and Cao, Rui-Ji and Ouyang, Shu and Zhou, Kun-Shu and Southon, John R. and Liu, Guo-Hai, Long-Living Lotus: Germination and Soil Gamma-Irradiation of Centuries-Old Fruits, and Cultivation, Growth, and Phenotypic Abnormalities of Offspring, American Journal of Botany, vol. 89, no. 2, pp. 236--247, February 2002. doi: 10.3732/ajb.89.2.236. Abstract
   Sacred lotus (Nelumbo nucifera) has been cultivated as a crop in Asia for thousands of years. An ∼1300-yr-old lotus fruit, recovered from an originally cultivated but now dry lakebed in northeastern China, is the oldest germinated and directly (14)C-dated fruit known. In 1996, we traveled to the dry lake at Xipaozi Village, China, the source of the old viable fruits. We identified all of the landmarks recorded by botanist Ichiro Ohga some 80 yr ago when he first studied the deposit, but found that the fruits are now rare. We (1) cataloged a total of 60 lotus fruits; (2) germinated four fruits having physical ages of 200-500 yr by (14)C dating; (3) measured the rapid germination of the old fruits and the initially fast growth and short dormancy of their seedlings; (4) recorded abnormal phenotypes in their leaves, stalks, roots, and rhizomes; (5) determined γ-radiation of ∼2.0 mGy/yr in the lotus-bearing beds; and (6) measured stratigraphic sequences of the lakebed strata. The total γ-irradiation of the old fruits of 0.1-3 Gy (gray, the unit of absorbed dosage defined as 1 joule/kg; 1 Gy = 100 rad), evidently resulting in certain of the abnormal phenotypes noted in their seedlings, represents the longest natural radiobiology experiment yet recorded. Most of the lotus abnormalities resemble those of chronically irradiated plants exposed to much higher irradiances. Though the chronic exposure of the old fruits to low-dose γ-radiation may be responsible in part for the notably weak growth and mutant phenotypes of the seedlings, it has not affected seed viability. All seeds presumably repair cellular damage before germination. Understanding of repair mechanisms in the old lotus seeds may provide insight to the aging process applicable also to other organisms.
9. Jones, James A., Overcoming Delayed Germination of Nelumbo Lutea, Botanical Gazette, vol. 85, no. 3, pp. 341--343, May 1928. doi: 10.1086/333846. Abstract
   1. In spite of the presence of a large number of small pores in the seed coat, the seeds of Nelumbo lutea did not absorb water and germinate, even after eighteen months' soaking at room temperature. 2. When the seed coats were broken without injuring the embryos, the seeds germinated without exception. 3. Seeds may be prepared for germination by treatment for five hours with concentrated sulphuric acid, following by thorough washing in tap water and later by drying on a screen to eliminate immediate germination. Seeds so treated may be stored by the commercial grower and shipped dry as ordered.
10. Shaw, Margaret Fenton, A Microchemical Study of the Fruit Coat of Nelumbo Lutea, American Journal of Botany, vol. 16, no. 5, pp. 259--276, 1929. doi: 10.1002/j.1537-2197.1929.tb09480.x.
11. Van Bergen, Pim F. and Hatcher, Patrick G. and Boon, Jaap J. and Collinson, Margaret E. and {de Leeuw}, Jan W., Macromolecular Composition of the Propagule Wall of Nelumbo Nucifera, Phytochemistry, vol. 45, no. 3, pp. 601--610, June 1997. doi: 10.1016/S0031-9422(96)00880-1. Abstract
    The macromolecular constituents of the sclerotic propagule wall of Nelumbo nucifera and seed coat of Nymphaea caerulea were studied using scanning electron- and light microscopy in combination with Curiepoint pyrolysis-gas chromatography-mass spectrometry. In addition, the Nelumbo material was analyzed using solid state 13C nuclear magnetic resonance and in-source pyrolysis-mass spectrometry. The sclerotic seed coat of the Nymphaea caerulea revealed the presence of angiosperm lignin-cellulose similar to that found in most sclerotic plant remains. In sharp contrast, the fruit wall plus seed coat of Nelumbo is believed to be composed of a complex of polysaccharides, based on primarily galactose and mannose units, and insoluble tannins, which are suggested to play the same structural role as the lignin-cellulose in the sclerotic seed coat. The distinctive nature of the chemical constituents present in the propagule wall of Nelumbo, supports the systematic distinction of this genus in the separate family Nelumbonaceae. The characteristic chemical composition of the propagule walls of Nelumbo could be an additional factor in favour of a prolonged longevity of these fruits. However, the distinctive composition of polysaccharides and tannins without the presence of lignin is considered to be the main reason for the absence of these propagules in the fossil record, despite their physical resistance.
12. Meyer, William C., Dormancy and Growth Studies of the American Lotus, Nelumbo Lutea, Plant Physiology, vol. 5, no. 2, pp. 225--234, April 1930. url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC440211/. Abstract
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13. Masuda, Jun-Ichiro and Urakawa, Toshihiro and Ozaki, Yukio and Okubo, Hiroshi, Short Photoperiod Induces Dormancy in Lotus (Nelumbo Nucifera), Annals of Botany, vol. 97, no. 1, pp. 39--45, January 2006. doi: 10.1093/aob/mcj008. Abstract
    BACKGROUND AND AIMS: Lotus (Nelumbo nucifera) has been cultivated as an ornamental and food plant in Japan for more than 1000 years. As large areas are required for its cultivation (approximately 2 m2 per plant), physiological research, such as into the effect of environmental factors on dormancy, has not been well studied until recently. In this paper, seedlings were used to examine environmental factors affecting dormancy induction. METHODS: In a first experiment, seeds were sown from 6 April to 6 October at 2-month intervals, and cultivated for 2 months in an unheated greenhouse. In a second experiment, seeds were prepared for germination on 16 November and 16 May and the seedlings were grown at 25 or 30 degrees C under natural daylength in phytotron growth rooms. After 1 month, the seedlings were cultivated at 20, 25 or 30 degrees C for a further month. The number of leaves and rhizome branches on the main stem were counted, and growth of rhizomes on the main stem was calculated using a rhizome enlargement index (= maximum internode diameter/internode length) after 2 months of culture in both experiments. KEY RESULTS: Rhizomes elongated without enlargement when the seeds were sown in April and June. Sowing the seeds in August and October resulted in rhizome enlargement from the tenth and fifth internodes, respectively. Rhizomes enlarged in the November-sowing but elongated in the May-sowing irrespective of temperature treatments under natural daylength in the phytotron rooms. The seedlings cultivated from May at 25-30 degrees C for 2 months had more leaves, and more rhizome branches and nodes than those cultivated from November. CONCLUSIONS: Short days led to induced dormancy in lotus.
14. Im, Myung-Hee and Kim, Byoung-Woon and Park, Yong-Seo and Yang, Seung-Yul and Song, Chyae-Eun and Heo, Buk-Gu, Effects of Scarification, Temperature and Sulfuric Acid Treatments on Seed Germination of White Lotus (Nelumbo nucifera), Korean Journal of Plant Resources, vol. 25, no. 1, pp. 7--13, 2012. doi: 10.7732/kjpr.2012.25.1.007. Abstract
    연 종자의 발아 특성을 구명하기 위해 전남 무안산 백련 종자를 이용해 종피의 파상부위, 발아 온도, 황산용액 처리 농도 및 시간별에 따른 종자 무게 변화와 발아율을 조사하였다. 종자를 파상하지 않고 파종한 것은 15일째가 되어도 전혀 발아가 되지 않았다. 그러나 기부를 파상하여 {$<$}TEX{$>\$$}25\textasciicircum\{\textbackslash circ\}C\${$<$}/TEX{$>$}에서 발아를 시킨 것은 6일 만에 100\%가 발아 되어 가장 우수한 결과를 보였다. 종자를 물에 침적시켰을 때 물에 뜬 것(0.90 g)과 가라앉은 것(1.18 g) 모두 발아 되었으나 침적된 종자를 {$<$}TEX{$>\$$}25\textasciicircum\{\textbackslash circ\}C\${$<$}/TEX{$>$}에서 발아 시켰을 때 발아세가 가장 좋았다. 황산처리는 80\% 용액에서 40-160분간 침적처리 했을때 6일째에 100\%가 발아해 가장 우수한 발아세를 나타내었다. 종자 채취 후 0개월, 12개월 및 24개월 된 것을 파종한 결과 발아세와 발아율에 차이가 없었다. 위와 같은 결과는 연의 종자번식에 도움이 될 것으로 사료된다. This study was conducted to determine the effects of scarification temperature, and sulfuric acid treatments on seed germination of white lotus collected from the Muan districts, Jeonnam in Korea. Without scarification, white lotus seeds were not germinated at all at 15 days after seeding. However, seeds sacrificed at basal parts showed 100\% germination rate at {$<$}TEX{$>\$$}25\textasciicircum\{\textbackslash circ\}C\${$<$}/TEX{$>$} 6 days after seeding. All the seeds floated (0.90 g) and soaked (1.18 g) in the water were completely germinated. Especially, the lotus seeds soaked in the water at {$<$}TEX{$>\$$}25\textasciicircum\{\textbackslash circ\}C\${$<$}/TEX{$>$} showed high germination rate. Seeds treated with 80\% sulfuric acid for 40-160 hours were germinated completely within 6 days after seeding. No difference in seed germination rate of white lotus stored up to 0, 12 and 24 months after harvest was observed. Overall results would be useful means for propagation and production of white lotus.
15. Libao, Cheng and Yuyan, Han and Minrong, Zhao and Xiaoyong, Xu and Zhiguang, Shen and Chunfei, Wang and Shuyan, Li and Zhubing, Hu, Gene Expression Profiling Reveals the Effects of Light on Adventitious Root Formation in Lotus Seedlings (Nelumbo Nucifera Gaertn.), BMC Genomics, vol. 21, no. 1, pp. 707, October 2020. doi: 10.1186/s12864-020-07098-5. Abstract
    Lotus is an aquatic horticultural crop that is widely cultivated in most regions of China and is used as an important off-season vegetable. The principal root of lotus is degenerated, and adventitious roots (ARs) are irreplaceable for plant growth. We found that no ARs formed under darkness and that exposure to high-intensity light significantly promoted the development of root primordia. Four differential expression libraries based on three light intensities were constructed to monitor metabolic changes, especially in indole-3-acetic acid (IAA) and sugar metabolism.
16. Francko, David A., Studies on Nelumbo Lutea (Willd.) Pers. I. Techniques for Axenic Liquid Seed Culture, Aquatic Botany, vol. 26, pp. 113--117, January 1986. doi: 10.1016/0304-3770(86)90009-4. Abstract
    Several techniques for the sterile liquid germination and cultivation of Nelumbo lutea (Willd.) Pers. seeds were evaluated. Surface disinfestation with ethanol, hypochlorite and detergent washes did not eliminate bacterial or fungal contamination of cultures upon seedling germination. Sequential washings in ethanol/hypochlorite and two incubations in sterile media containing antibiotics (streptomycin sulfate and penicillin G) and a fungicide (Captan) induced sterility in ca. 34\% of cultures, while maintaining {$>$}98\% germination rates in inoculated seeds. Seedlings elongated and differentiated normally in sterile culture.
17. Ushimaru, Takashi and Kanematsu, Sumio and Katayama, Masao and Tsuji, Hideo, Antioxidative Enzymes in Seedlings of Nelumbo Nucifera Germinated under Water, Physiologia Plantarum, vol. 112, no. 1, pp. 39--46, 2001. doi: 10.1034/j.1399-3054.2001.1120106.x. Abstract
    Dry seeds of anoxia-tolerant lotus (Nelumbo nucifera Gaertn=Nelumbium speciosum Willd.) have green shoots with plastids containing chlorophyll, so photosynthesis starts even in seedlings germinated under water, namely hypoxia. Here we investigated antioxidative enzyme changes in N. nucifera seedlings responding to oxygen deficiency. The activity of superoxide dismutase (SOD; EC 1.15.1.1), dehydroascorbate reductase (DHAR; EC 1.8.5.1) and glutathione reductase (GR; EC 1.6.4.2) were lower in seedlings germinated under water (submerged condition) in darkness (SD seedlings) than those found in seedlings germinated in air and darkness (AD seedlings). In contrast, ascorbate peroxidase (APX; EC 1.11.1.11) activity was higher in SD seedlings and the activity of catalase (EC 1.11.1.6) and monodehydroascorbate reductase (MDAR; EC 1.6.5.4) in SD seedlings was nearly the same as in AD seedlings. When SD seedlings were exposed to air, the activity of SOD, DHAR and GR increased, while the activity of catalase and MDAR decreased. Seven electrophoretically distinct SOD isozymes were detectable in N. nucifera. The levels of plastidic Cu,Zn-SODs and Fe-SOD in SD seedlings were comparable with those found in AD seedlings, which may reflect the maintenance of green plastids in SD seedlings as well as in AD seedlings. These results were substantially different from those previously found in rice seedlings germinated under water.
18. Sayre, Jeff, Propagation Protocol for American Lotus ( Nelumbo Lutea Willd.), Native Plants Journal, vol. 5, no. 1, pp. 14--17, 2004. doi: 10.1353/npj.2004.0017. Abstract
    The Native Plants Journal 5.1 (2004) 14-17
19. Ding, YanFen and Cheng, HongYan and Song, SongQuan, Changes in Extreme High-Temperature Tolerance and Activities of Antioxidant Enzymes of Sacred Lotus Seeds, Science in China Series C: Life Sciences, vol. 51, no. 9, pp. 842--853, September 2008. doi: 10.1007/s11427-008-0107-8. Abstract
    Sacred lotus (Nelumbo nucifera Gaertn. ‘Tielian’) seed is long-lived and extremely tolerant of high temperature. Water content of lotus and maize seeds was 0.103 and 0.129 g H2O [g DW] −1, respectively. Water content, germination percentage and fresh weight of seedlings produced by surviving seeds gradually decreased with increasing treatment time at 100°C. Germination percentage of maize (Zea mays L. ‘Huangbaogu’) seeds was zero after they were treated at 100°Cfor 15 min and that of lotus seeds was 13.5\% following the treatment at 100°C for 24 h. The time in which 50\% of lotus and maize seeds were killed by 100°C was about 14.5 h and 6 min, respectively. With increasing treatment time at 100°C, relative electrolyte leakage of lotus axes increased significantly, and total chlorophyll content of lotus axes markedly decreased. When treatment time at 100°C was less than 12 h, subcellular structure of lotus hypocotyls remained fully intact. When treatment time at 100°C was more than 12 h, plasmolysis gradually occurred, endoplasmic reticulum became unclear, nuclei and nucleoli broke down, most of mitochondria swelled, lipid granules accumulated at the cell periphery, and organelles and plasmolemma collapsed. Malondialdehyde (MDA) content of lotus axes and cotyledons decreased during 0 −12 h of the treatment at 100°C and then increased. By contrast, the MDA content of maize embryos and endosperms increased during 5–10 min of the treatment at 100°C and then decreased slightly. For lotus seeds: (1) activities of superoxide dismutase (SOD) and glutathione reductase (GR) of axes and cotyledons and of catalase (CAT) of axes increased during the early phase of treatment at 100°C and then decreased; and (2) activities of ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR) of axes and cotyledons and of CAT of cotyledons gradually decreased with increasing treatment time at 100°C. For maize seeds: (1) activities of SOD and DHAR of embryos and endosperms and of GR of embryos increased during the early phase of the treatment at 100°C and then decreased; and (2) activities of APX and CAT of embryos and endosperms and of GR of endosperms rapidly decreased with increasing treatment time at 100°C. With decrease in seed germination, activities of SOD, APX, CAT, GR and DHAR of axes and cotyledons of lotus seeds decreased slowly, and those of embryos and endosperms of maize seeds decreased rapidly.
20. Chu, Pu and Chen, Huhui and Zhou, Yuliang and Li, Yin and Ding, Yu and Jiang, Liwen and Tsang, Edward W. T. and Wu, Keqiang and Huang, Shangzhi, Proteomic and Functional Analyses of Nelumbo Nucifera Annexins Involved in Seed Thermotolerance and Germination Vigor, Planta, vol. 235, no. 6, pp. 1271--1288, June 2012. doi: 10.1007/s00425-011-1573-y. Abstract
    Annexins are multifunctional proteins characterized by their capacity to bind calcium ions and negatively charged lipids. Although there is increasing evidence implicating their importance in plant stress responses, their functions in seeds remain to be further studied. In this study, we identified a heat-induced annexin, NnANN1, from the embryonic axes of sacred lotus (Nelumbo nucifera Gaertn.) using comparative proteomics approach. Moreover, the expression of NnANN1 increased considerably in response to high-temperature treatment. Quantitative real-time PCR (qRT-PCR) revealed that the transcripts of NnANN1 were detected predominantly during seed development and germination in sacred lotus, implicating a role for NnANN1 in plant seeds. Ectopic expression of NnANN1 in Arabidopsis resulted in enhanced tolerance to heat stress in transgenic seeds. In addition, compared to the wild-type seeds, transgenic seeds ectopically expressing NnANN1 exhibited improved resistance to accelerated aging treatment used for assessing seed vigor. Furthermore, transgenic seeds showed enhanced peroxidase activities, accompanied with reduced lipid peroxidation and reduced ROS release levels compared to the wild-type seeds. Taken together, these results indicate that NnANN1 plays an important role in seed thermotolerance and germination vigor.
21. Jaganathan, Ganesh K. and Song, Danping and Liu, Wei and Han, Yingying and Liu, Baolin, Relationship between Seed Moisture Content and Acquisition of Impermeability in Nelumbo Nucifera (Nelumbonaceae), Acta Botanica Brasilica, vol. 31, pp. 639--644, 2017-Oct-Dec. doi: 10.1590/0102-33062017abb0188. Abstract
    ABSTRACT Seeds of Nelumbo nucifera do not imbibe water, and thus have physical dormancy (PY). However, a proportion of seeds are permeable to water, and so we hypothesized that variation in moisture content is a reason for the development of both permeable and impermeable seeds. The permeable proportion of seeds present in a lot collected from Suzhou, China, was separated using an imbibition test. The permeable proportion had an average moisture content of 15.6 \%, compared with 8.5 \% for impermeable seeds. Drying permeable seeds above silica gel to 10 \% and 8 \% f. wb., resulted in 77 and 100 \% impermeable seeds, respectively, compared with no impermeable seeds at 15 \% moisture content. Dried to 10 \% moisture content, and incubated above water in an airtight container, 46 \% of the seeds reverse impermeability. Permeable seeds with 15 \% moisture content maintained above LiCl2 (RH=70 \%) did not develop impermeability after three months of storage. The seeds dried to 6 \% moisture content and stored above water in an airtight container showed no increase in moisture. Based on these results, we conclude that there is a strong relationship between moisture content and the onset of impermeability in this species.
22. Ohga, Ichiro, The Germination of Century-Old and Recently Harvested Indian Lotus Fruits, with Special Reference to the Effect of Oxygen Supply, American Journal of Botany, vol. 13, no. 10, pp. 754--759, 1926. doi: 10.1002/j.1537-2197.1926.tb05908.x.
23. Hongpakdee, P. and Samranyat, C. and Ruamrungsri, S., Propagation of Sacred Lotus (Nelumbo Nucifera Gaertn.) by Stolon Cutting with Active Bud and Different Nodes Number, Acta Horticulturae, no. 1263, pp. 233--240, November 2019. doi: 10.17660/ActaHortic.2019.1263.30. Abstract
    Sacred lotus is one of the valuable economic cut flowers in Thailand and Asian countries. The growers usually propagate by cutting stolon segment, since this technique allows cloning to supply uniform planting stock. They however consider that only longer stolon cutting with many nodes and active buds would be suitable as propagules. To clarify this condition, the effect of vegetative propagation technique by node number on plant growth and flowering in 'Sattabutsaya' sacred lotus was conducted with 3 stolon cutting types i.e., stolon cutting with 1, 2 and 3 nodes, respectively, using a completely randomized design. All active stolons were planted singly in 1.20×1.00 m circular concrete pots, filled with 1/3 clay soil and 2/3 tap water under natural conditions (May to August 2016). It was found that increasing node number of cutting material increased in total leaf number at 6 weeks after planting (WAP). None of the stolon cutting treatments affected total leaf area, new internode length, flower stalk length and flower length at 3 months after planting. Nevertheless, planting sacred lotus with single node stolon cuttings gave the lowest new stolon length, flower number, percentage of flowering and delay more 2-3 weeks of flowering. Triple nodes of propagated stolon cutting gave the best result in plant dry weight components (flower, pod, new stolon and fibrous root). Planting sacred lotus stolon cuttings with 2 or 3 nodes did not affect total leaf number, new stolon length and girth and visible flowering time. It could be concluded that stolon cuttings with at least two nodes for propagative material is sufficient for creating plant stock for flowering lotus production.
24. Nohara, Seiichi and Tsuchiya, Takayoshi, Effects of Water Level Fluctuation on the Growth of Nelumbo Nucifera Gaertn. in Lake Kasumigaura, Japan, Ecological Research, vol. 5, no. 2, pp. 237--252, 1990. doi: 10.1007/BF02346994. Abstract
    Investigations were made of the growth of Nelumbo nucifera, an aquatic higher plant, in a natural stand in Lake Kasumigaura. A rise of 1.0 m in the water level after a typhoon in August 1986 caused a subsequent decrease in biomass of N. nucifera from the maximum of 291 g d.w. m−2 in July to a minimum of 75 g d.w. m−2. The biomass recovered thereafter in shallower regions. The underground biomass in October tended to increase toward the shore. The total leaf area index (LAI) is the sum of LAI of floating leaves and emergent leaves. The maximum total LAI was 1.3 and 2.8 m2 m−2 in 1986 and 1987, respectively. LAI of floating leaves did not exceed 1 m2 m−2. The elongation rates of the petiole of floating and emergent leaves just after unrolling were 2.6 and 3.4 cm day−1, respectively. The sudden rise in water level (25 cm day−1) after the typhoon in August 1986 caused drowning and subsequent decomposition of the mature leaves. Only the young leaves were able to elongate, allowing their laminae to reach the water surface. The fluctuation in water level, characterized by the amplitude and duration of flooding and the time of flooding in the life cycle, is an important factor determining the growth and survival of N. nucifera in Lake Kasumigaura.
25. Hall, Thomas F. and Penfound, William T., The Biology of the American Lotus, Nelumbo Lutea (Wild.) Pers, The American Midland Naturalist, vol. 31, no. 3, pp. 744--758, 1944. doi: 10.2307/2421417. Abstract
    1. The American lotus, Nelumbo lutea (Willd.) Pers. is a perennial, emergent, aquatic herb with fibrous, adventitious roots, slender rhizomes, elongated tubers, erect and floating leaves, large fragrant, yellow flowers, and an obconic toms containing acorn-like fruits. 2. The roots are characterized by a large, aerenchymous cortex; the rhizome, tubers, petioles, and peduncles are distinguished by a small cortex, scattered bundles, and four to eight large air tubes; the midveins of the leaf are characterized by upper and lower masses of collenchyma, closed bundles, and air tubes in a groundwork of parenchyma. 3. The rapid colonization of new areas by lotus is accomplished by the elongated rhizomes and to a less extent by tubers and fruits. Complete inundation of lotus colonies for a continuous period of two weeks or dewatering for one month destroyed all the leaves and flowers and many of the rhizomes and tubers. 4. The American lotus provides favorable environmental conditions for the development of malaria mosquitoes, but it can be controlled effectively by recurrent cutting of the leaves where the water is relatively turbid.
26. Nohara, Seiichi and Kimura, Makoto, Growth Characteristics of Nelumbo Nucifera Gaertn. in Response to Water Depth and Flooding, Ecological Research, vol. 12, no. 1, pp. 11, April 1997. doi: 10.1007/BF02523605. Abstract
    Three experiments on the effects of water depth and flooding onNelumbo nucifera Gaertn. were made in the artificial environment of concrete ponds. First, plants were harvested in autumn after growing under seven different water levels ranging from 0.2–3 m The number of floating leaves, the total number of leaves and the leaf area index of emergent leaves were greatest in the tanks at 0.5 m depth. The petiole dry weight per unit length of emergent leaves and the ratio of aboveground to belowground biomass rose with increasing water depth up to 2 m. In contrast, that of floating leaves was constant at about 10 mg dry weight cm−1. The proportion of biomass in tubers fell from 20\% at 0.2 m to 6\% at 2 m. Second, petiole elongation responses to the amplitude of flooding were investigated in early summer. The maximum rate of petiole elongation was 25 cm per day at 2.4 m water depth. This was the maximum depth at whichN. nucifera could grow. No petioles could elongate from 3 m to 5 m depth. Finally, the effects of timing of flooding on growth were investigated. At the end of growing season, the belowground biomass of plants in the flooding treatment in late summer was smallest among the flooding treatment plants (P{$<$}0.05), and was most severe when flooding occurred in this season. Based on the results of these experiments, the growth characteristics ofN. nucifera in relation to petiole elongation, biomass allocation, and flooding tolerance were discussed.
27. Blaylock, A. J and Seymour, R. S, Diaphragmatic Nets Prevent Water Invasion of Gas Canals in Nelumbo Nucifera, Aquatic Botany, vol. 67, no. 1, pp. 53--59, May 2000. doi: 10.1016/S0304-3770(99)00087-X. Abstract
    This study measured pore size in the net-like diaphragms of the lotus (Nelumbo nucifera Gaertn.) and the water pressures necessary to break their menisci. Mean pore radii were 7.0±0.3μm (95\% confidence interval) in the rhizome and 19.0±0.5μm in the petiole. Nets in the rhizomes could prevent internal flooding in water depths up to 2m, which corresponds approximately to the depths at which natural stands of the lotus grow. Nets in the emergent petioles could withstand only 0.5m of water pressure, but there was no relationship between pore radius and the proximity of a net to the rhizome. Their role may be to reduce the kinetic energy of incoming water.
28. Masuda, Jun-ichiro and Ozaki, Yukio and Okubo, Hiroshi, Rhizome Transition to Storage Organ Is under Phytochrome Control in Lotus (Nelumbo Nucifera), Planta, vol. 226, no. 4, pp. 909--915, September 2007. doi: 10.1007/s00425-007-0536-9. Abstract
    We examined photoperiodic response of lotus (Nelumbonucifera) rhizome morphogenesis (its transition to a storage organ) by using seed-derived plants. Rhizome enlargement (increase in girth) was brought about under 8, 10 and 12~h photoperiods, whereas the rhizomes elongated under 13 and 14~h photoperiods. Rhizomes elongated under 14~h light regimes supplied as 8~h of natural light plus 6~h supplemental hours of white, yellow or red light, but similar treatments with supplemental blue, green or far red light, caused enlargement in girth of the rhizomes. A 2~h interruption of the night with white, yellow or red light, in plants entrained to 8~h photoperiod brought rhizome elongation, whereas 2~h-blue, green or far red light night breaks still resulted in rhizome increase in girth. The inhibitory effect of a red (R) light night break on rhizome increase in girth was reversed by a far-red (FR) light given immediately afterwards. Irradiation with R/FR/R inhibited the rhizome increase in girth. FR light irradiation following R/FR/R irradiation cancelled the effect of the last R light irradiation. It was demonstrated that the critical photoperiod for rhizome transition to storage organ is between 12 and 13~h photoperiod. It was also evident that the optimal light quality range for interruption of dark period (night break) is between yellow and red light and that a R/FR reversible reaction is observed. From these results, we propose that phytochrome plays an important role in photoperiodic response of rhizome increase in girth in lotus. This is the first report on phytochrome-dependent morphogenesis of storage organs in rhizomous plants.
29. Masuda, Junichiro and Yoshimizu, Shohei and Ozaki, Yukio and Okubo, Hiroshi, Rhythmic Response of Rhizome Growth to Light-Break in Lotus (Nelumbo Nucifera), Journal of the Faculty of Agriculture, Kyushu University, vol. 52, no. 1, pp. 35--38, February 2007. doi: 10.5109/9277. Abstract
    We examined the response of rhizome growth to red light–break under different short daylengths in lotus (Nelumbo nucifera) seedlings. Maximum inhibitory response of rhizome enlargement to light–break under 10, 8 and 4 hr daylengths occurred 10, 8–10 and 12–14 hrs after the beginning of the dark period, respectively. It was found that rhythmic response to light–break is involved in rhizome growth of lotus.
30. Hongpakdee, P. and Ruamrungsri, S., Enhanced Flowering of Sacred Lotus (Nelumbo Nucifera Gaertn.) by Extending the Photoperiod with Supplemental Lighting Techniques, Acta Horticulturae, no. 1171, pp. 47--52, September 2017. doi: 10.17660/ActaHortic.2017.1171.7. Abstract
    Sacred lotus (Nelumbo nucifera Gaertn.) is one of the most popular cut flowers in Thailand and other Asian countries, commonly used for religious purposes. However, basic knowledge regarding the control of flowering is relatively lacking. The effects of photoperiod on growth of N. nucifera were investigated using a completely randomized design experiment with six day-length conditions: 1) 11 h for 2 months, 2) 11 h for 1 month and then to 13 h for 1 month, 3) 11 h for 1 month and then 15 h for 1 month, 4) 13 h for 1 month and then 11 h for 1 month, 5) 13 h for 2 months and 6) 13 h for 1 month and then 15 h for 1 month. Each pot was planted with 90 stem cuttings, filled to 2/3 of the pot level with natural clay soil and then filled to 3/4 of the pot level with tap water after planting. The stolons were grown under natural conditions (ambient temperature 30/18°C with an 11 h day length in mild winter from January-February 2013). Night interruption after 6:00 pm was used to induce a long day-length condition (13 and 15 h). None of photoperiod conditions affected the total number of leaves. However, extending the photoperiod from 11 to 15 h and from 13 to 15 h and a constant photoperiod of 13 h produced the largest leaves. Shortened photoperiods from 13 to 11 h decreased the flowering percentage and number of flowers. Extended photoperiods from 11 to 13 h, 11 to 15 h and 13 to 15 h only increased the flowering percentage compared with that of constant photoperiods of 11 and 13 h. Nevertheless, the extended photoperiod delayed the date of visible flowering.
31. Abd Rasid, N. S. and Naim, M. N. and Che Man, H. and Abu Bakar, N. F. and Mokhtar, M. N., Evaluation of Surface Water Treated with Lotus Plant; Nelumbo Nucifera, Journal of Environmental Chemical Engineering, vol. 7, no. 3, pp. 103048, June 2019. doi: 10.1016/j.jece.2019.103048. Abstract
    The potential of Nelumbo nucifera in treating contaminated surface water was investigated in terms of biochemical oxygen demand (BOD), chemical oxygen demand (COD), turbidity, and nitrate reduction. Batch type lab-scale container cultivated with N. nucifera was exposed to the contaminated surface water for 30 days. Nitrate (NO3−) adsorption and pH level were monitored continuously to identify the plant survival and to avoid any additional contaminants into the samples such as plant decay. For comparison, water lily, Nymphaea, was prepared using the same experimental setup. After 30 days of phytoremediation, the BOD and COD values of the treated water using N. nucifera was significantly reduced to 97.1\% and 55\%, respectively, due to the unique gas transport mechanism that thermodynamically drive O2 gas from leaves at the water surface to the buried rhizomes located in the anoxic sediments. When treated with Nymphaea, the BOD value in water decreased by 64.5\% and the COD value increased by 50.5\%. The results indicate that N. nucifera was able to remove the organic contaminants from the surface water by supplying adequate amount of 0.2–2.1\,mL/min O2 gas to increase the microbial activities from the control condition.
32. Tsuchiya, Takayoshi and Nohara, Seiichi, Growth and Life Span of the Leaves of Nelumbo Nucifera Gaertn. in Lake Kasumigaura, Japan, Aquatic Botany, vol. 36, no. 1, pp. 87--95, December 1989. doi: 10.1016/0304-3770(89)90094-6. Abstract
    Growth of leaves of Nelumbo nucifera Gaertn. in Lake Kasumigaura was investigated with special emphasis on leaf dynamics. Floating leaves were found throughout the growing period, while emergent leaves were not found until July. However, emergent leaves contributed approximately 75\% of the total leaf area index at its seasonal maximum, 2.76 m2 m−2. Mean leaf life span of emergent leaves with thick laminae and stiff petioles was much longer than that of floating leaves (44.5 vs. 17.1 days).
33. Libao, Cheng and {yuyan}, Han and Huiying, Liu and Runzhi, Jiang and Shuyan, Li, Transcriptomic Analysis Reveals Ethylene’s Regulation Involved in Adventitious Roots Formation in Lotus (Nelumbo Nucifera Gaertn.), Acta Physiologiae Plantarum, vol. 41, no. 6, pp. 97, May 2019. doi: 10.1007/s11738-019-2895-9. Abstract
    Adventitious roots (ARs) play an irreplaceable role in~the uptake of water and nutrients due to under-developed principle root in plants. The process of ARs formation is affected by plant hormone. In this study, by employing High-Throughout Tag-sequencing Technique and ELISA method, we analyzed of the transcriptome and indole-3-acetic acid (IAA) content to monitor the changes of metabolism regulated by ethylene signaling in lotus. Exogenous application of ethephon (ethylene~precursor) dramatically accelerated ARs development, and while restrained by 1-methylcyclopropene (1-MCP, the ethylene perception inhibitor), indicating the crucial role ethylene in ARs development. Transcriptomic analysis showed that both treatment of ethephon and 1-MCP dramatically altered the expression of numerous genes. In total, transcriptional expressions of 694 genes were induced and 554 genes were suppressed in ETH/CK0 stages compared with MCP/CK0 stages. Most of these up-regulated genes exhibited the one-three folds changes. In ETH/MCP libraries, we found nine and five genes involved in the metabolism or transcriptional responses to ethylene and IAA, and fourteen genes, which were considered to NAC, bHLH, AP2-EREBP, MYB, LOB, bHLH and bZIP families, respectively, exhibited an increase in transcriptional level. In addition, an enhanced mRNA levels of seven genes [1-aminocyclopropane-1-carboxylate oxidase (ACO), leucine-rich repeat receptor, pectinesterase, pyruvate decarboxylase, ethylene oxide synthase, respiratory burst oxidase homolog protein and xyloglucan endotransglucosylase] relevant to ARs formation were detected in was detected in ETH/MCP libraries. Furthermore, we found that IAA content was obviously decreased after applications were detected on ethephon and 1-MCP. However, the decreased IAA level in 1-MCP treatment was more pronounced than that in ethephon treatment, and kept a low level during the whole periods of ARs development. Taken together, our findings provided a comprehensive understanding of ethylene’s regulation during ARs formation in lotus seedlings.
34. Liu, Amei and Tian, Daike and Xiang, Yanci and Mo, Haibo, Effects of Biochar on Growth of Asian Lotus (Nelumbo Nucifera Gaertn.) and Cadmium Uptake in Artificially Cadmium-Polluted Water, Scientia Horticulturae, vol. 198, pp. 311--317, January 2016. doi: 10.1016/j.scienta.2015.11.030. Abstract
    To further understand the benefits of biochar in crop production and remediation of heavy metal pollution, the effects of biochar on the growth of Nelumbo nucifera ‘Taikong 36’ and cadmium (Cd) accumulation in plant tissues were evaluated in the artificially Cd-polluted water-soil. The results showed that plant biomass significantly increased with the proportion (0–32\%) of biochar in the soil mix. However, the impacts of biochar on plant physiological indicators were not clear. Compared with the control, the addition of 32\% biochar significantly decreased Cd content in rhizomes, petioles, and leaves of N. nucifera ‘Taikong 36’ by 69, 81, 55\%, respectively. Correspondingly, the bioaccumulation coefficient of Cd was reduced, by a maximum of 71\%, and the Cd transfer coefficient from underground to aboveground tissues increased up to 1.3 fold. The bioaccumulation coefficient of Cd in rhizomes was significantly lower than that of leaves, indicating that biochar mitigated the effect of heavy metal ions and reduced the accumulation of Cd in the edible parts of lotus. Therefore, biochar has potential in green agriculture production and remediation of heavy-metal polluted water and soil due to its positive effects: improving plant growth and reducing heavy metal pollution.
35. Ming, Ray and VanBuren, Robert and Liu, Yanling and Yang, Mei and Han, Yuepeng and Li, Lei-Ting and Zhang, Qiong and Kim, Min-Jeong and Schatz, Michael C. and Campbell, Michael and Li, Jingping and Bowers, John E. and Tang, Haibao and Lyons, Eric and Ferguson, Ann A. and Narzisi, Giuseppe and Nelson, David R. and {Blaby-Haas}, Crysten E. and Gschwend, Andrea R. and Jiao, Yuannian and Der, Joshua P. and Zeng, Fanchang and Han, Jennifer and Min, Xiang Jia and Hudson, Karen A. and Singh, Ratnesh and Grennan, Aleel K. and Karpowicz, Steven J. and Watling, Jennifer R. and Ito, Kikukatsu and Robinson, Sharon A. and Hudson, Matthew E. and Yu, Qingyi and Mockler, Todd C. and Carroll, Andrew and Zheng, Yun and Sunkar, Ramanjulu and Jia, Ruizong and Chen, Nancy and Arro, Jie and Wai, Ching Man and Wafula, Eric and Spence, Ashley and Han, Yanni and Xu, Liming and Zhang, Jisen and Peery, Rhiannon and Haus, Miranda J. and Xiong, Wenwei and Walsh, James A. and Wu, Jun and Wang, Ming-Li and Zhu, Yun J. and Paull, Robert E. and Britt, Anne B. and Du, Chunguang and Downie, Stephen R. and Schuler, Mary A. and Michael, Todd P. and Long, Steve P. and Ort, Donald R. and William Schopf, J. and Gang, David R. and Jiang, Ning and Yandell, Mark and {dePamphilis}, Claude W. and Merchant, Sabeeha S. and Paterson, Andrew H. and Buchanan, Bob B. and Li, Shaohua and {Shen-Miller}, Jane, Genome of the Long-Living Sacred Lotus (Nelumbo Nucifera Gaertn.), Genome Biology, vol. 14, no. 5, pp. R41, May 2013. doi: 10.1186/gb-2013-14-5-r41. Abstract
    Sacred lotus is a basal eudicot with agricultural, medicinal, cultural and religious importance. It was domesticated in Asia about 7,000 years ago, and cultivated for its rhizomes and seeds as a food crop. It is particularly noted for its 1,300-year seed longevity and exceptional water repellency, known as the lotus effect. The latter property is due to the nanoscopic closely packed protuberances of its self-cleaning leaf surface, which have been adapted for the manufacture of a self-cleaning industrial paint, Lotusan.
36. Tian, Daike and Tilt, Ken M. and Sibley, Jeff L. and Dane, Fenny and Woods, Floyd M., Response of Lotus (Nelumbo Sp.) to Container Soil Volume, Journal of Environmental Horticulture, vol. 27, no. 2, pp. 79--84, June 2009. doi: 10.24266/0738-2898-27.2.79. Abstract
    The effect of soil volume on containerized lotus (Nelumbo) production has been underreported. American lotus (Nelumbo lutea Willd.) and three cultivars (‘Embolene’, ‘98 Seed’ and ‘Karizma’) of Asian lotus (N. nucifera Gaertn.) were investigated for growth response to container soil volume in this study. Electrical conductivity, pH, plant growth indices, and plant nutritional content were influenced by container soil volume. Differences in some plant growth indices were significant between treatments with ½ and higher (½ and ¾) container height soil (CHS) in 21 or 29 liter (\#5 or \#7) containers. However, plant growth indices were generally not different between treatments with ½ and ¾ CHS. Lotus planted in containers with ¼ CHS usually produced the greatest plant height and underground fresh weight, while the largest number of propagules often occurred in containers with ½ or ¾ CHS. The highest number of emerging leaves was observed in plants with ¼ or ½ CHS treatments, with no significant difference in emerging leaf number between lotus grown in containers with ½ and ¾ CHS. Flower number generally decreased as soil level increased. The ¼ and ½ CHS were more efficient than ¾ CHS for lotus production in containers.
37. Nguyen, Q. V and Hicks, D and {Rural Industries Research and Development Corporation (Australia)} and {Asian Foods Research and Development}, Exporting Lotus to Asia: An Agronomic and Physiological Study : A Report for the Rural Industries Research and Development Corporation, 2001.
38. Wang, Yanjie and Yuan, Man and Li, Zexin and Niu, Yeqing and Jin, Qijiang and Zhu, Bin and Xu, Yingchun, Effects of Ethylene Biosynthesis and Signaling on Oxidative Stress and Antioxidant Defense System in Nelumbo Nucifera G. under Cadmium Exposure, Environmental Science and Pollution Research, vol. 27, no. 32, pp. 40156--40170, November 2020. doi: 10.1007/s11356-020-09918-3. Abstract
    Water contamination with cadmium (Cd) is a global environmental problem and its remediation becomes urgent. Phytoremediation using ornamental plants has attracted much attention for its advantages of cost-effectiveness and beautification of the environment. Nelumbo nucifera G. is a popular ornamental aquatic macrophyte with fast growth, large biomass, and high capacities for Cd accumulation and removal. However, information about Cd resistance and defense responses in N. nucifera is rather scarce, which restricts its large-scale utilization for phytoremediation. The phytohormone ethylene plays an important role in plant resistance to Cd stress, but the underlying mechanism remains unclear. In this study, we investigated morphophysiological responses of N. nucifera seedlings to Cd stress, and focused on the effects of ethylene on oxidative damage, Cd accumulation, and antioxidant defense system at the metabolic and transcript levels in leaves under Cd stress. Our results showed that Cd exposure led to leaf chlorosis and necrosis, coupled with an increase in contents of hydrogen peroxide, electrolyte leakage, and malondialdehyde, and decrease in chlorophyll content. Exogenous ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) application intensified Cd-induced stress responses and Cd accumulation, and increased ethylene production by inducing ACC synthase (ACS) gene NnACS. Such enhanced ethylene emission inhibited catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) activities, and modulated ascorbate (AsA) and glutathione (GSH) accumulation through transcriptional regulation of their respective metabolic genes. After ethylene action inhibitor silver thiosulfate (STS) supplementation, Cd-induced oxidative damage was abolished, and Cd content declined but still at a relatively high level. Blocking of ethylene perception by STS inhibited ethylene biosynthesis; enhanced CAT, APX, and GR activities and their transcript levels; increased AsA accumulation via inducing its biosynthetic genes; but reduced GSH content and NnGSH2 expression level. These results suggest that ethylene biosynthesis and signaling play an important role in N. nucifera response to Cd stress, and maintaining appropriate ethylene level and low ethylene sensitivity could improve its Cd tolerance via efficient antioxidant defenses.
39. {La-ongsri}, Woranuch and Trisonthi, Chusie and Balslev, Henrik, Management and Use of Nelumbo Nucifera Gaertn. in Thai Wetlands, Wetlands Ecology and Management, vol. 17, no. 4, pp. 279--289, August 2009. doi: 10.1007/s11273-008-9106-6. Abstract
    Management and use of Nelumbo nucifera Gaertn.—the lotus plant—was studied in 58 wetlands distributed throughout Thailand. Although traditionally harvested in extractive systems depending on natural wetlands, N. nucifera is now increasingly being managed. Two hundred eighty informants mentioned 20 different uses, mainly for food, medicine, and religious rites, in both subsistence and cash economies. The uses of N. nucifera appeared to be rather generalized throughout the country even if informants in the northern and central regions knew of more uses and ways of commercializing its products, possibly related to the abundance of wetlands and natural stand in those regions, and maybe also cultural differences.
40. Williamson, P. S. and Schneider, E. L., Nelumbonaceae, pp. 470--473, 1993. doi: 10.1007/978-3-662-02899-5_55. Abstract
    Herbaceous aquatic perennial developing horizontal rhizomes and tubers. Roots adventitious, produced at nodes. Phyllomes distributed in sets of three along the rhizome (one foliage leaf, two fleshy cataphylls). Foliage leaves simple, peltate, emergent and floating, producing latex. Petioles of emergent leaves terete, to 2 m in length, bearing prickles. Blades concave, large, 10–100 cm in diameter, orbiculate, entire, bluish green adaxially and remarkably water-repellent. Flowers solitary, perfect, actinomorphic, hypogynous, 10–100 cm across, pink to white or yellowish, elevated above water on terete peduncles up to 2 m in length; floral phyllotaxy spiral; perianth caducous; sepals 2–5; petals ca. 20–30; stamens 200–300, filaments elongate, bearing four introrsely to latrorsely dehiscent anthers, terminated by claw-like, thermogenic appendage. Gynoecium of 2–30 free carpels embedded in the truncate surface of the enlarged obconical, spongy receptacle; each carpel with a distinct, circular stigma with a central canal into the ovary; ovule solitary, ventral-apical, pendulous, anatropous, bitegmic-crassinucellar. Fruits globose or elongate ovoid, with the carpel wall adnate to the testa forming a hard-walled nut, filled by the edible embryo, embedded in an enlarged, dry, sclerified receptacle. Embryo with two thick and fleshy cotyledons surrounding a green plumule, the latter enclosed by a delicate stipule-like sheath. Radicle non-functional. Endosperm minute, helobial, lacking perisperm; seeds exalbuminous.
41. {Ping-he}, Wei and {Wei-pei}, Chen and {Rui-yang}, Chen, Study on the Karyotype Analysis of Nymphaeaceae and Its Taxonomic Position, Journal of Systematics and Evolution, vol. 32, no. 4, pp. 293, July 1994. url: https://www.jse.ac.cn/EN/. Abstract
    The present paper reports the karyotypes of six species in the family...
42. Ishizuna, Fumiko and Tsutsumi, Nobuhiro, Flower Bud Formation of Sacred Lotus (Nelumbo Nucifera Gaertn.): A Case Study of ‘Gyozankouren’ Grown in a Container, HortScience, vol. 49, no. 4, pp. 516--518, April 2014. doi: 10.21273/HORTSCI.49.4.516. Abstract
    The genus Nelumbo consists of two species, N. nucifera and N. lutea. N. nucifera is an ornamental and edible plant that is widely cultivated. Earlier studies of sacred lotus (N. nucifera) flowers focused mainly on morphology, phyllotaxis, leaf arrangements, and flower development. During the growing season, sacred lotus produces one foliage leaf at each node. Flower buds emerge from the abaxial side of the basal part of the foliage leaf. However, the number of blooming flowers is much less than the number of foliage leaves. Little is known concerning flower bud formation during lotus plant development. This is the first experimental study to reveal that every node has one flower bud even in the dormant shoot apex and that most of the formed flower buds aborted in the course of floral development. Our results suggest that flower bud formation of sacred lotus is independent of daylength. On the other hand, whether a formed bud reaches blooming may depend on environmental factors.
43. Lin, Zhongyuan and Zhang, Cheng and Cao, Dingding and Damaris, Rebecca Njeri and Yang, Pingfang, The Latest Studies on Lotus (Nelumbo Nucifera)-an Emerging Horticultural Model Plant, International Journal of Molecular Sciences, vol. 20, no. 15, pp. 3680, July 2019. doi: 10.3390/ijms20153680. Abstract
    Lotus (Nelumbo nucifera) is a perennial aquatic basal eudicot belonging to a small family Nelumbonaceace, which contains only one genus with two species. It is an important horticultural plant, with its uses ranging from ornamental, nutritional to medicinal values, and has been widely used, especially in Southeast Asia. Recently, the lotus obtained a lot of attention from the scientific community. An increasing number of research papers focusing on it have been published, which have shed light on the mysteries of this species. Here, we comprehensively reviewed the latest advancement of studies on the lotus, including phylogeny, genomics and the molecular mechanisms underlying its unique properties, its economic important traits, and so on. Meanwhile, current limitations in the research of the lotus were addressed, and the potential prospective were proposed as well. We believe that the lotus will be an important model plant in horticulture with the generation of germplasm suitable for laboratory operation and the establishment of a regeneration and transformation system.
44. Deng, Jiao and Chen, Sha and Yin, Xiaojian and Wang, Kun and Liu, Yanling and Li, Shaohua and Yang, Pingfang, Systematic Qualitative and Quantitative Assessment of Anthocyanins, Flavones and Flavonols in the Petals of 108 Lotus (Nelumbo Nucifera) Cultivars, Food Chemistry, vol. 139, no. 1, pp. 307--312, August 2013. doi: 10.1016/j.foodchem.2013.02.010. Abstract
    Petal colour is one of the major characteristics that determine the ornamental value of lotus. To assess the contribution of different flavonoids to this character, composition and content of anthocyanins, flavones and flavonols were analysed through high performance liquid chromatography coupled with photodiode array detection tandem electrospray ionisation triple quad mass spectrometry in 108 lotus cultivars with red, pink, yellow, white and red/white pied petal colours. Totally, five anthocyanins and fourteen flavones and flavonols were detected and quantified. In general, the yellow, white and pied species hardly contained any anthocyanins; red cultivars contain more than pink cultivars. Among the five anthocyanins, malvidin 3-O-glucoside was the most abundant one in all the cultivars that contain anthocyanin. The fourteen flavones and flavonols belonged to four groups based on their aglycones. Except for the yellow cultivars, kaempferol-derivatives were the most abundant one. These data might be helpful in lotus breeding for different colours.
45. Wang, Yanjie and Chen, Yeqing and Yuan, Man and Xue, Zeyun and Jin, Qijiang and Xu, Yingchun, Flower Color Diversity Revealed by Differential Expression of Flavonoid Biosynthetic Genes in Sacred Lotus, Journal of the American Society for Horticultural Science, vol. 141, no. 6, pp. 573--582, November 2016. doi: 10.21273/JASHS03848-16. Abstract
    Sacred lotus (Nelumbo nucifera) is an important aquatic ornamental plant which contains several diverse flower colors, but the underlying mechanisms of its flower coloration remain unclear. In this study, seven complementary DNA (cDNA) clones of genes involved in flavonoid biosynthesis, including chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), flavonoid 3′-hydroxylase (F3′H), flavonoid 3′,5′-hydroxylase (F3′5′H), dihydroflavonol 4-reductase (DFR), and anthocyanidin synthase (ANS), were isolated and characterized. Moreover, expression patterns of these seven genes and pigment profiles were investigated across four N. nucifera cultivars with different flower colors: Zhongguohongbeijing [ZGH (red)], Xinghuafen [XHF (pink)], Molingqiuse [MLQS (yellow)], and Zhufengcuiying [ZFCY (white)]. Real-time quantitative polymerase chain reaction (qRT-PCR) analysis showed that during flower development, transcripts of early biosynthetic genes (NnCHS, NnCHI, and NnF3H) were abundant at the early stage; noticeably, highest expression of NnCHI in MLQS probably induced abundant anthoxanthin synthesis and displayed yellow. Expression of late biosynthetic genes, especially NnDFR and NnANS, was generally consistent with change patterns of anthocyanins in ZGH and XHF, but NnF3′H was barely detectable in the pink cultivars. Meanwhile, negligible expression of NnDFR and NnANS was detected in MLQS and ZFCY, respectively, which blocked their colored anthocyanin biosynthesis. Spatial expression analysis revealed that most flavonoid biosynthetic genes were highly expressed in floral tissues, rather than leaves. These results suggest that in N. nucifera cultivars with different flower colors, flavonoid biosynthesis is differentially regulated by the expression of these flavonoid biosynthetic genes, among which, NnCHI, NnF3′H, NnDFR, and NnANS are supposed to be critical for pigment accumulation, and therefore, affect different flower coloration.
46. Zhang, Weiwei and Tian, Daike and Huang, Xiu and Xu, Yuxian and Mo, Haibo and Liu, Yanbo and Meng, Jing and Zhang, Dasheng, Characterization of Flower-Bud Transcriptome and Development of Genic SSR Markers in Asian Lotus (Nelumbo Nucifera Gaertn.), PLOS ONE, vol. 9, no. 11, pp. e112223, November 2014. doi: 10.1371/journal.pone.0112223. Abstract
    Background Asian lotus (Nelumbo nucifera Gaertn.) is the national flower of India, Vietnam, and one of the top ten traditional Chinese flowers. Although lotus is highly valued for its ornamental, economic and cultural uses, genomic information, particularly the expressed sequence based (genic) markers is limited. High-throughput transcriptome sequencing provides large amounts of transcriptome data for promoting gene discovery and development of molecular markers. Results In this study, 68,593 unigenes were assembled from 1.34 million 454 GS-FLX sequence reads of a mixed flower-bud cDNA pool derived from three accessions of N. nucifera. A total of 5,226 SSR loci were identified, and 3,059 primer pairs were designed for marker development. Di-nucleotide repeat motifs were the most abundant type identified with a frequency of 65.2\%, followed by tri- (31.7\%), tetra- (2.1\%), penta- (0.5\%) and hexa-nucleotide repeats (0.5\%). A total of 575 primer pairs were synthesized, of which 514 (89.4\%) yielded PCR amplification products. In eight Nelumbo accessions, 109 markers were polymorphic. They were used to genotype a sample of 44 accessions representing diverse wild and cultivated genotypes of Nelumbo. The number of alleles per locus varied from 2 to 9 alleles and the polymorphism information content values ranged from 0.6 to 0.9. We performed genetic diversity analysis using 109 polymorphic markers. A UPGMA dendrogram was constructed based on Jaccard’s similarity coefficients revealing distinct clusters among the 44 accessions. Conclusions Deep transcriptome sequencing of lotus flower buds developed 3,059 genic SSRs, making a significant addition to the existing SSR markers in lotus. Among them, 109 polymorphic markers were successfully validated in 44 accessions of Nelumbo. This comprehensive set of genic SSR markers developed in our study will facilitate analyses of genetic diversity, construction of linkage maps, gene mapping, and marker-assisted selection breeding for lotus.
47. Seymour, Roger S. and {Schultze–Motel}, Paul, Physiological Temperature Regulation by Flowers of the Sacred Lotus, Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, vol. 353, no. 1371, pp. 935--943, June 1998. doi: 10.1098/rstb.1998.0258. Abstract
    Flowers of the sacred lotus, Nelumbo nucifera Gaertn. (Nelumbonaceae) are thermogenic and physiologically thermoregulatory. The 42 g flowers remain between 30–36°C during a 2 to 4–day period despite fluctuations in environmental temperatures between about 10–45°C. As the ambient temperature drops, the flowers increase heat production in proportion. Temperature regulation apparently occurs at a cellular level, by a steep, reversible thermal inhibition of respiration at flower temperatures above 30°C. There was a marked time lag between change in flower temperature and compensatory response, suggesting regulation through a biochemical feedback mechanism rather than structural changes in enzymes or membranes. By oxidizing carbohydrate, the flowers produce up to 1 W, with about half of the heat coming from the 8.5 g carpellary receptacle. The period of temperature regulation begins before petal opening and continues through the period of stigma receptivity. Temperature regulation may reward insect pollinators with a warm, equable environment, or it possibly enhances and coordinates flower development.
48. Deng, Xianbao and Zhu, Lingping and Fang, Ting and Vimolmangkang, Sornkanok and Yang, Dong and Ogutu, Collins and Liu, Yanling and Han, Yuepeng, Analysis of Isoquinoline Alkaloid Composition and Wound-Induced Variation in Nelumbo Using HPLC-MS/MS, Journal of Agricultural and Food Chemistry, vol. 64, no. 5, pp. 1130--1136, February 2016. doi: 10.1021/acs.jafc.5b06099. Abstract
    Alkaloids are the most relevant bioactive components in lotus, a traditional herb in Asia, but little is known about their qualitative and quantitative distributions. Here, we report on the alkaloid composition in various lotus organs. Lotus laminae and embryos are rich in isoquinoline alkaloids, whereas petioles and rhizomes contain trace amounts of alkaloids. Wide variation of alkaloid accumulation in lamina and embryo was observed among screened genotypes. In laminae, alkaloid accumulation increases during early developmental stages, reaches the highest level at full size stage, and then decreases slightly during senescence. Vegetative and embryogenic tissues accumulate mainly aporphine-type and bisbenzylisoquinoline-type alkaloids, respectively. Bisbenzylisoquinoline-type alkaloids may be synthesized mainly in lamina and then transported into embryo via latex through phloem translocation. In addition, mechanical wounding was shown to induce significant accumulation of specific alkaloids in lotus leaves.
49. Tungmunnithum, Duangjai and Renouard, Sullivan and Drouet, Samantha and Blondeau, Jean-Philippe and Hano, Christophe, A Critical Cross-Species Comparison of Pollen from Nelumbo Nucifera Gaertn. vs. Nymphaea Lotus L. for Authentication of Thai Medicinal Herbal Tea, Plants, vol. 9, no. 7, pp. 921, July 2020. doi: 10.3390/plants9070921. Abstract
    "Bau Luang" or Nelumbo nucifera Gaertn. is an aquatic medicinal herb that has been used as a component of traditional medicines, medicinal products, and herbal tea for good health, particularly in Asia. The stamen of N. nucifera is an important part of this medicinal plant that is used in the form of dried and/or powdered stamens for herbal tea as well as the main ingredient of some traditional remedies. However, there is another aquatic herb called "Bau Sai" or Nymphaea lotus L. that is distributed in similar locations. Living plants of these two aquatic species may be classified according to their morphology, but the dried and powdered stamens of these two medicinal species are difficult to distinguish. The major reason of adulteration is the higher price of Bau Luang stamen. As a result, various methods of authentication, such as pollen micromorphology evaluation using scanning electron microscopy (SEM) analysis, bioinformatics analysis of two nuclear and plastic DNA markers, phytochemical stamen profiling, and Fourier transform infrared (FTIR) analysis of stamen plant material authentication from Bau Luang and Bau Sai, have been used in this present research in order to avoid some adulteration and/or misuse between the dried stamens of Bau Luang and Bau Sai. These results showed that the micro-morphology of pollen (size of pollen grain, number of apertures, and surface ornamentation) from the SEM analysis, some phytochemical compounds and the FTIR sporopollenin-to-protein ratio signal analysis are potential tools for authentication and identification of these two medicinal plants from their dried-stamen materials. This model of investigation may also be used to distinguish dried plant material from other problematic plant groups.
50. Nickovic, S. and Vukovic, A. and Vujadinovic, M. and Djurdjevic, V. and Pejanovic, G., Technical Note: High-Resolution Mineralogical Database of Dust-Productive Soils for Atmospheric Dust Modeling, Atmospheric Chemistry and Physics, vol. 12, no. 2, pp. 845--855, January 2012. doi: 10.5194/acp-12-845-2012. Abstract
    {$<$}p{$><$}strong class="journal-contentHeaderColor"{$>$}Abstract.{$<$}/strong{$>$} Dust storms and associated mineral aerosol transport are driven primarily by meso- and synoptic-scale atmospheric processes. It is therefore essential that the dust aerosol process and background atmospheric conditions that drive dust emissions and atmospheric transport are represented with sufficiently well-resolved spatial and temporal features. The effects of airborne dust interactions with the environment determine the mineral composition of dust particles. The fractions of various minerals in aerosol are determined by the mineral composition of arid soils; therefore, a high-resolution specification of the mineral and physical properties of dust sources is needed. {$<$}br{$><$}/br{$>$} Several current dust atmospheric models simulate and predict the evolution of dust concentrations; however, in most cases, these models do not consider the fractions of minerals in the dust. The accumulated knowledge about the impacts of the mineral composition in dust on weather and climate processes emphasizes the importance of including minerals in modeling systems. Accordingly, in this study, we developed a global dataset consisting of the mineral composition of the current potentially dust-producing soils. In our study, we (a) mapped mineral data to a high-resolution 30 s grid, (b) included several mineral-carrying soil types in dust-productive regions that were not considered in previous studies, and (c) included phosphorus.{$<$}/p{$>$}
51. Miyake, K., Some Physiological Observations on Nelumbo Nucifera, Gærtn, Shokubutsugaku Zasshi, vol. 12, no. 141, pp. en85-en101, 1898. doi: 10.15281/jplantres1887.12.85.