Desmanthus illinoensis

Propagation

Germination

[3] [4] [5]

Scarification is necessary for good germination of illinoensis. Without scarification, seed germination is 5-8%.[1] However, some accessions have much higher unscarified germination rates (43-48%). These seeds do still benefit from scarification.[2] The differences might be explained by the age of the seeds at harvest time and/or post-harvest seed coat changes.[3][4]

Scarification can be achieved by mechanical means[1][2][3][4], by fire/heat exposure[3][1], and chemical methods[3][4].

Both artificial and natural stratification do not affect the germination rate, though multi-year cycles have not been studied.[1][3]

A razor blade can be used to cut off “a small piece of the chalazal end” of the seed.[2]

Soaking seeds in concentrated sulfuric acid for 10 minutes results in 93% germination which is significantly higher than 1 minute (12%). This was not significantly different than soaking for 30 minutes (79%).[3]

The addition of potassium nitrate does not enhance the germination of unscarified seeds.[3]

In a broad comparison of mechanical, chemical, and heat seed scarification methods, mechanical performed the best in terms of final germination percentage.[3]

The use of rotary drum scarifiers for large-scale production is feasible, but the seeds should be monitored for excessive damage to the seed coat.[5] Seeds of the Marc, Bayamo, and Uman cultivars of “Desmanthus” (D. virgatus, D. leptopyllus, and D. pubescens) can be similarly treated en masse by immersion in boiling water for 5 seconds followed promptly by cold water before drying and storage.[6]

The response of illinoensis seeds to temperature-based scarification is likely adaptive to prairie fires.[1][3]

If mold is present, illinoensis seeds can be surface disinfected by steeping in 0.6% sodium hypochlorite plus 15 drops of detergent containing triclosan per liter for five minutes then rinsed in running water for five minutes.[1]

Vegetative

In-Vitro

Cultivation

[3]

Harvest

Illinoensis seeds can be stored long-term at 4°C. It is recommended that seeds be used within two months if stored at room temperature to maintain research rigor[1]. Germination after 31 years of storage in an unprotected drawer remains high (60-89%) so the recommendation is probably excessively restrictive.[2] Similar results were noted for seeds stored at 16°C and 40% RH.[4]

Yield

In a Rhizobium inoculation trial, illinoensis plants achieved a root fresh-weight yield of 5.6-8.0 g per plant growing in 300 ml pots after 12 weeks in greenhouse conditions. The plants grew to an average height of 45-52 cm. Root dry weight was not given. Importantly, plants received nitrogen and phophorus free nutrients throughout the duration of the study.[7] If we assume a planting density of 25 per square meter (20 cm × 20 cm planting), that equates to a time-space yield of 20-30 g/m2/day fresh roots. Given conservative estimates of the drying ratio (0.5) and root bark proportion (0.5), that’s about 6 grams dry root bark per square meter per day.

Soilless

Soil

Fertilization

Temperature

Lighting

Pests

Illinoensis seed heads are susceptible to infestation by Bruchidae family beetles. Anomoea laticlavia and A. flavokansiensis beetles feed on the young vegetation and flowering parts, limiting the seed set of the plants.[8][9]

Ecology

Illinoensis are nodulated by Rhozobium bacteria.[8]

Morphology

[7]

Roots

Stem

Leaves

Inflorescence

Seeds

[1]

Phytochemistry

Infraspecific Variation

Biosynthesis

Distribution

Timecourse

Improvement

Identification

Inheritance

Methods

History & Society

Work Log

02 Sep 2023

Germination seems to have slowed in the treatment trials. A couple of groups have succumbed to what appears to be damp off. Others have a fungal infection.

I also gave a subjective count of the number of what appears to be viable seeds for transplant: The seedlings with true leaves forming without contamination or obvious defects.

Accession 4 seems to have done the best out of all control group. For seed cleaning operations, accession 4 was briefly pulsed in a blender to remove the seeds from the hulls. I suspect this abrasion was the cause of the high no-pretreatment germination but also the cause of some of the noticable damage to the cotyledons of those seedlings.

Given the complete loss of the group with the highest germination (2-1), I think it would be wise to disinfect the seeds prior to any further tests.

27 Aug 2023

Moved 3-1(b-g) seed group into individual vials and placed in refrigerator.

24 Aug 2023

Seed treatments:

• boiling water for 5 seconds
• sulfuric acid for 10 minutes
• manual scarification with sandpaper
• control
• boiling water for 5 seconds then drying and storage
• germination in germ chamber (30°C) or tent (20-24°C)

Groups of 25 seeds each. Accession 3 will be subjected to multiple storage and pretreatment conditions. All others will be tested with boiling water and no pretreatment only. Twenty-one treatment groups of 525 seeds total. All seeds stored in 0.5ml brown centrifuge tubes.

Hypothesis: Boiling as a pretreatment before drying, storage, and sale is safe and effective though not at effective as manual scarification. Boiling before storage has a miniscule effect on the germination of seeds stored at 4°C but a minor effect with storage at room temperature. Storage followed by boiling is equally effective compared to the reverse order.

• germinate 25 seeds each from accessions 1, 2, 3, 4 in germinator
• Immerse 200 seeds from accession 3 for 5 seconds in boiling water
• Immediately cool in RT water
• germinate one batch (1a) immediately in germinator (30°C)
• germinate one batch (1h) immediately in tent (RT)
• Dry rest (6 groups) with unheated airflow for > 3 days
• Separate into 25 seed batches
• Store according to group number (RT or refrigerator)
• Immerse 25 seeds from accession 3 in concentrated sulfuric acid for 10 min
• Rinse profusely with water for 5 min
• Germinate immediately in germinator
• Manually scarify 25 seeds from accession 3
• Germinate immediately in germinator

Storage times: 182 days, 365 days

If I feel like it, I might replicate 3x which would be more statistically rigorous.

The remainder of the cleaned seeds will be stored in the refrigerator, so they can be used for storage studies as well.

06 Aug 2023

Collected 4 accessions of illinoensis from around my city. GPS-tagged photos were taken at each location. Seeds were harvested from a single plant for each accession. Sample leaf was taken from each plant.

Seeds were put into a dehydrator without heat.

Bibliography

1. Olszewski, M.W. and D'Agostino, J.A. and Groch, A.F. and Vertenten, C.M., Germination and Seed Coat Histology of Physically Dormant Desmanthus Illinoensis Seeds, Seed Science and Technology, vol. 41, no. 1, pp. 36--49, April 2013. doi: 10.15258/sst.2013.41.1.04. Abstract
   Illinois bundleflower (Desmanthus illinoensis) is a legume used in meadow and prairie restoration seed mixes in the United States of America. An important constituent of grasslands, there is little information on the natural mechanisms of seed germination, the structure of the seed coat or the locations of impermeability within the seed coat. Germination and histological studies were conducted to examine the effect of various environmental factors on dormancy of Illinois bundleflower and to elucidate structures of the 'hard' seed coat. Following mechanical scarification and incubation between blotters moistened with distilled water, final germination percentage (FGP) was 86-100\% at three temperature regimes (11/23, 20/30 or 32°C); however, FGP declined and mean days to 50\% germination (Dx, an inverse measure of germination rate) increased at 11/23°C and -0.4 MPa. Brief exposure of the funiculus and nearby lens to fire resulted in permeable seeds and increased FGP to 74\% and decreased Dx to 2.1 days compared with control seeds (FGP = 9\%; Dx = 5.8 days). Impermeability was caused by 'caps' on outer palisade tangential walls, by inner palisade adjacent hour-glass cells within natural U-shaped fissures called the pleurogram, and by palisade radial/transverse walls within epidermal fractures. Physical dormancy was broken following brief exposure of the lens to fire that resulted in lens palisade lifting and palisade obliterations, which rendered seeds permeable. Dye tracking using 1\% Azure II stain indicated that the lifted lens was the primary site of imbibition. We conclude that high temperatures resulting from fire is probably a significant environmental cue of physical dormancy break for seeds of Illinois bundleflower.
2. Kelting, Ralph W., Longevity of Illinois Bundle Flower (Desmanthus Illinoensis) Seeds, The Southwestern Naturalist, vol. 39, no. 2, pp. 212--213, 1994. doi: 10.2307/3672256.
3. Schnell, Judy Kaye, Seed Ecology of Illinois Bundleflower (Desmanthus Illinoensis)., October 1990. url: https://esirc.emporia.edu/handle/123456789/1385. Abstract
   Seed ecology of Illinois bundleflower (Desmanthus illinoensis) was studied by looking at several aspects of ecology. Germination at varying temperatures with six different scarifying techniques was assessed. Scarification, which included mechanical and chemical, was observed at 10C, 13C, 17C, and 24C. Germination rates varied from 2\% to 99\%, depending on treatment. Germination increased with all scarification treatments and suggests that germination is inhibited by an extremely hard seed coat. Heat treatments simulating fire were applied for eight seconds and thirty seconds at temperatures ranging from 100C to 500C at 50C intervals. Germination percentage of all heat-treated seeds was greater than the control. This indicates that Illinois bundleflower could be considered a fire species. The effect of moisture stress on Illinois bundleflower seed germination was determined using mannitol as the osmoticum. Mannitol solutions varying from -0.033 MPa to -2.5 MPa were used to germinate Illinois bundleflower seeds after a 10 minute scarification in concentrated sulfuric acid. Illinois bundleflower seeds germinated at water potentials as low as -1.0 MPa. This suggests that Illinois bundleflower seeds can germinate at relatively low soil water potentials. Xylem pressure potentials of Illinois bundleflower seedlings were measured to determine lethal water potentials reached before death. Scarified seeds (10 minutes in concentrated sulfuric acid) were germinated, then planted 50 to a pot and placed in the greenhouse. Plants were watered every other day until they were 6" high. Two pots were kept as watered controls and water was withheld from all other plants. Xylem pressure potentials of the plants were checked with a pressure chamber. After obtaining xylem pressure potentials, the plants were watered and observed to see if plants recovered or died. Illinois bundleflower seedlings withstood 15 days of drought conditions and a xylem pressure potential of -3.5 MPa. Any xylem pressure potential below -3.5 MPa resulted in death for the seedlings. The possibility for ley farming techniques was applied using Illinois bundleflower in an established wheat field. Plots were established and seeded at a rate of 10 lbs/a, or 171 seeds in a 9 ft2 plot. Seeds were scarified in concentrated sulfuric acid for 10 minutes before planting. Rows of Illinois bundleflower were planted between wheat rows and the plots were checked periodically for establishment. Plants were counted by row and plot. Biomass will be checked after this year's wheat harvest (i.e. year 2).
4. Call, C. A., Storage Life of Illinois Bundleflower and Western Indigo Seed, Journal of Range Management, vol. 38, no. 6, pp. 500, November 1985. doi: 10.2307/3899740.
5. Olszewski, Michael W. and Young, Courtney A. and Sheffield, Joel B., Germination and Seedling Growth of Desmanthus Illinoensis and Desmodium Canadense in Response to Mechanical Scarification, HortScience, vol. 45, no. 10, pp. 1554--1558, October 2010. doi: 10.21273/HORTSCI.45.10.1554. Abstract
   Illinois bundleflower [Desmanthus illinoensis (Michx.) MacMill. ex B.L. Rob. \& Fernald] and showy ticktrefoil [Desmodium canadense (L.) DC.] are legumes native to North America used during meadow restoration efforts. However, insufficient or slow germination or reduced emergence may result attributable to seedcoat-mediated reductions in permeability to water. The objective of this research was to determine the effectiveness of a single-speed electric scarifier lined with 40-grit sandpaper for increasing germination and seedling growth of two native legumes. Seeds of Illinois bundleflower and showy ticktrefoil were mechanically scarified for 3, 6, or 12 s before they were subjected to germination and vigor testing. After scarification, final germination percentage (FGP), germination rate, and uniformity at multiple temperatures (15, 20, and/or 20 to 30 °C) were improved for Illinois bundleflower. However, FGP decreased for showy ticktrefoil, whereas germination rate and uniformity increased. For both species, there was a decline in FGP with longer scarification durations. Illinois bundleflower seed subjected to scarification and accelerated aging (AA) had higher FGP than non-scarified seed subjected to AA (59\% and 6\%, respectively), whereas both scarified and non-scarified seed of showy ticktrefoil subjected to AA had low FGP (11\% and 18\%, respectively). Mechanical scarification increased electrical conductivity (EC) of leachates for both species, but scarified showy ticktrefoil seed subjected to AA resulted in the highest EC compared with all other treatments, indicating a reduction of vigor. Evaluation of a seedling grow-out test 3 weeks after sowing confirmed that emergence was enhanced after 3 s of mechanical scarification of Illinois bundleflower seed but that scarification of showy ticktrefoil seed decreased emergence and increased the number of abnormal seedlings. Mechanical scarification resulted in peripheral damage and seed tissue obliteration of both species as indicated by viewing with a stereomicroscope. We conclude that scarifier limitations caused excessive physical damage of showy ticktrefoil. For Illinois bundleflower, however, mechanical scarification using an electric scarifier increased emergence from 18\% (non-scarified seed) to 77\% after 3 s of scarification and FGP from 32\% (non-scarified seed) to 87\% after 3 s of scarification. Compared with responses from non-scarified Illinois bundleflower seeds, scarification treatment also resulted in 24\% faster germination and 37\% more uniformity.
6. Hopkinson, Jamie E. and English, Bernard H., Germination and Hardseededness in Desmanthus, Tropical Grasslands, vol. 38, no. 1, pp. 1--16, March 2004. url: http://era.daf.qld.gov.au/id/eprint/484/. Abstract
   The mechanisms and control of hardseededness in the 3 Australian cultivars of the genus Desmanthus were investigated in a series of experiments in which the effects of various seedsoftening treatments, particularly boiling water, were measured. Desmanthus seed is predominantly hard, only defective seeds being normally otherwise. As it has only very brief, early embryo dormancy, hardseededness is the only serious barrier to germination. Seed is most readily softened through rupture of the palisade at the lens (strophiole). The lens is of a typically mimosaceous type which is readily ruptured by immersion in boiling water or less readily by application of pressure to adjacent parts of the testa. Ruptures may consist only of separation of the palisade from underlying tissue, which alone does not confer permeability; mostly they also result in fractures to the palisade that then render seeds irreversibly permeable. The palisade becomes reflective as it separates, which allows the event to be witnessed at the moment of separation if suitable pressure is applied to the testa of an individual seed while it is viewed under magnification. Brief (4–10 seconds) immersion of highquality seed in boiling water consistently softened a high proportion of seeds without causing serious damage. Extending the duration of immersion led to a progressive increase in the proportion of seed deaths. Neither previous boiling water treatment nor scarification damage to the testa materially affected results of treatment, but immature and small seeds behaved differently, being more vulnerable to damage than mature seed, and less likely to undergo lens rupture. Adaptation of boiling water treatment to farm-scale seed handling was simple and reliable. Commercial treatment of seed by an alternative method suitable for greater bulks and consisting of passage through a rice-whitener was checked and found to be successful through a combination of gentle scarification and lens rupture, both attributable to the numerous minor impacts of the process. Percentage emergence of seedlings from soil in the greenhouse closely followed percentage laboratory germination, except when inferior seed grades were included in the comparison, when emergence was poor. Very little seed softened in soil. Already-permeable seed either germinated rapidly or died, while buried hard seed mostly remained hard and viable even more than a year after sowing.
7. Shockley, F.W. and McGraw, R.L. and Garrett, H.E., Growth and Nutrient Concentration of Two Native Forage Legumes Inoculated with Rhizobium and Mycorrhiza in Missouri, USA, Agroforestry Systems, vol. 60, no. 2, pp. 137--142, March 2004. doi: 10.1023/B:AGFO.0000013269.19284.53. Abstract
   The Center for Agroforestry at the University of Missouri has tested numerous native legumes for potential use in agroforestry and selected Illinois bundleflower (Desmanthus illinoensis (Michaux) MacMillan ex Robinson and Fern.) and panicled tick clover (Desmodium paniculatum (L.) DC.) for further testing. Our objective was to document the effect of arbuscular mycorrhizae (AM) (Glomus spp.) and Rhizobium on growth and nutrient concentration of these legumes. Seeds were planted in a greenhouse and inoculated with one of two species of AM and/or one of two strains of Rhizobium. Plants were harvested after 80 d and data taken on leaf and stem dry weight, root fresh weight, stem height, nodulation, AM colonization, and N, P, K, Ca, and Mg concentration. Inoculation with Rhizobium did not affect plant growth in Illinois bundleflower, but colonization by Glomus intraradices increased all plant growth variables except stem height. Nutrient concentration was unaffected by the presence of either endophyte. In contrast, inoculation of panicled tick clover with Rhizobium str. 41Z10 increased leaf dry weight (32\%) compared to the control and root fresh weight (41\%) compared to str. 32Z3, and colonization by G. intraradices increased leaf dry weight (35\%) and stem height (26\%). Both species of AM increased P and K concentration (41\% and 55\%, respectively) in panicled tick clover. Our results suggest that the growth of these legumes can be improved by the use of proper AM species and/or Rhizobium strains. However, additional research to identify the best Rhizobium and AM inoculates for these plant species is important in developing strategies for their use in agroforestry.
8. Latting, June, The Biology of Desmanthus Illinoensis, Ecology, vol. 42, no. 3, pp. 487--493, 1961. doi: 10.2307/1932234.
9. Piper, Jon K., Density of Anomoea Flavokansiensis on Desmanthus Illinoensis in Monoculture and Polyculture, Entomologia Experimentalis et Applicata, vol. 81, no. 1, pp. 105--111, 1996. doi: 10.1111/j.1570-7458.1996.tb02020.x. Abstract
   The effect of plant species diversity on the density of the herbivore, Anomoea flavokansiensis Moldenke (Coleoptera: Chrysomelidae), on Desmanthus illinoensis (Michaux) MacMillan (Mimosaceae), a promising North American legume for exploring the principles of diverse, perennial grain agriculture was examined. From mid-June to early August A. flavokansiensis feeds on young leaves and inflorescences of D. llinoensis. At high density, A. flavokansiensis potentially reduces seed yield and is thus an important consideration for long-term stands that are to be grown without insecticides. The potential to manage this insect via intercropping its host species with other, non-host perennial species by monitoring A. flavokansiensis density on D. illinoensis within experimental monocultures, two-species mixtures with Tripsacum dactyloides, and three-species mixtures with T. dactyloides and Leymus racemosus was examined. Insects were censused 2–3 times weekly from mid-June to early August at two sites from 1991 to 1995. In the first three years, beetle density was generally low ({$<$}1 per plant), and did not differ among treatments. In the fourth year, however, beetle density peaked at 15 and 25 insects per plant at the two sites, and was highest within monoculture for most dates. In 1995, density was again low, but tended to remain higher in monoculture at one site. The results suggest that beetle density on D. illinoensis can be reduced in polyculture and may hold promise for the management of this insect herbivore within perennial grain polycultures.
10. Thompson, Alonzo C. and Nicollier, Gilles F. and Pope, Daniel F., Indolealkylamines of Desmanthus Illinoensis and Their Growth Inhibition Activity, ACS Publications, May 2002. doi: 10.1021/jf00075a020.