Dalea Research Articles

Biochar and Deactivated Yeast as Seed Coatings for Restoration: Performance on Alternative Substrates

Seedling establishment is often a critical bottleneck in the revegetation of mine tailings and similar substrates. Biochar and deactivated yeast are potential sustainable materials that could be used in this context as seed coatings to aid in seedling establishment. We conducted a greenhouse study on biochar and deactivated yeast use as seed coatings, assessing germination, establishment, and early growth of white clover (Trifolium repens) and purple prairie clover (Dalea purpurea). Coated seeds were applied to a mine tailing, a coarse granitic sand, and potting soil mix substrates; seedling establishment and growth were monitored over 75 days. Biochar coatings enhanced the seedling establishment of Trifolium, with biochar and biochar plus yeast coatings giving the best results. In some cases, these effects persisted throughout the experiment: biochar coatings resulted in a ~fivefold increase in Trifolium biomass at harvest for plants in the potting soil mix but had neutral effects on sand or tailings. Biochar seed coatings also enhanced Dalea germination in some cases, but the benefits did not persist. Our results indicate that biochar-based seed coatings can have lasting effects on plant growth well beyond germination but also emphasize highly species-specific responses that highlight the need for further study.

Influence of Temperature and Water Availability on Seed Germination of Cicer Milkvetch (Astragulus Cicer L.) and Purple Prairie Clover (Dalea Purpurea Vent. Var. Pupurea)

Global warming may leads a decrease in plant diversity and increased risk for some plant extinction does exist. The effect of temperature and water availability on seed germination were investigated in many plants, and are two of the most important factors on seed germination, for the plant survival that can result in a loss or increase under global climate change scenarios, by affecting a plant's recruitment success. Therefore, research on how climate change affects seed germination is essential for our research and ability to predict the risk for plants. To examine the possible effect of climate change on two commonly grown legumes a greenhouse experiment was run at at AAFC-SPARC. One was an introduced legume, cicer milkvetch, and the other a native legume, purple prairie clover. Our findings were: the experiment with warmer temperature and decreased soil moisture to research seed germination, the result is that reduction in the total both seed germination rate occurs, and showed the seed germination of purple prairie clover is better for the more stressful temperatures and water potentials examined in this experiment. For both legumes were examined on the control water potential the best temperature range is from 20℃ to 30℃ .

Native forbs interseeded into native grass pastures persist under grazing

AbstractIncorporating native forbs within native warm‐season grass (NWSG) pastures has the potential to benefit cattle, pollinators, and wildlife beyond that of NWSG monocultures. However, when grazing NWSG pastures, rotational stocking is recommended as opposed to continuous stocking. Therefore, to evaluate whether within‐season rest is needed for native pasture sustainability, two NWSG grazing experiments were conducted near Greeneville, TN, 2017–2020, to assess the persistence of native forbs when an 11‐species native forb blend was interseeded into established switchgrass (SG; Panicum virgatum L.) and big bluestem/indiangrass (BBIG; Andropogon gerardii Vitman and Sorghastrum nutans (L.) Nash) pastures. Each experiment was a completely randomized design with four replicates of each within‐season rest grazing treatment (no rest, early rest, middle rest, late rest, and no graze). Within‐season rest was not influential for NWSG tiller density or total forb plant density thus indicating persistence of forbs may not require rotational stocking. Purple prairie clover (Dalea purpurea Vent.) did not establish while Illinois bundleflower (Desmanthus illinoensis (Michx.) MacMill. ex B.L. Rob. & Fernald) was only observed flowering once despite having the greatest seeding rate among forbs. Based on establishment and flowering of the 11 species in the current mixture, interseeding a 6‐species polyculture of black‐eyed Susan (Rudbeckia hirta L.), dixie ticktrefoil (Desmodium tortuosum (Sw.) DC.), eastern purple coneflower (Echinacea purpurea (L.) Moench), lanceleaf coreopsis (Coreopsis lanceolata L.), Maximilian sunflower (Helianthus maximiliani Schrad.), and oxeye sunflower (Heliopsis helianthoides (L.) Sweet) could allow for plant biodiversity while offering floral resources for pollinators during the NWSG grazing season.

White Prairie Clover (Dalea candida Michx. ex Willd.) and Purple Prairie Clover (Dalea purpurea Vent.) in Binary Mixtures with Grass Species

Native forage legumes may have potential for summer/fall grazing in semiarid prairie regions in mixture with grasses. The objective of this study was to evaluate two native clovers in binary mixtures with the introduced grasses when harvested in July and September to simulate late summer or fall stockpile forage. Eight binary clover–grass mixtures were seeded in a split-plot design with 4 replications at Swift Current, Saskatchewan, Canada. Mixtures included (i) AC Antelope white prairie clover (WPC)-Admiral meadow bromegrass (MBG), (ii) WPC-AC Success hybrid bromegrass (HBG), (iii) WPC-Bozoisky Russian wildrye (RWR), (iv) WPC-TomRWR, (v) AC Lamour purple prairie clover (PPC)-AdmiralMBG, (vi) PPC-AC SuccessHBG, (vii) PPC-BozoiskyRWR, and (viii) PPC-TomRWR. Clover establishment differed (p = 0.03) in July where WPC had 77.8% greater proportion in mixture than PPC, although both clovers increased (p < 0.001) in September to similar legume proportions, 663.2 and 876.1 kg/ha, respectively. Clovers with bromegrasses produced 41.9% more forage dry matter yield in summer than clovers with Russian wildryes (p < 0.001), though the latter mixtures had slightly better nutritive value (avg. 7.0% vs. 5.2% crude protein (CP). Clover–MBG exhibited higher (53.6%) in vitro organic matter digestibility (IVOMD) than Clover–HBG (51.2%) (p = 0.04). Purple prairie clover with grass or both clovers in mixture with bromegrasses, produced adequate forage biomass for summer and fall grazing, except clovers with Bozoisky RWR, while clovers with both RWR cultivars had acceptable forage nutritive value for summer in this semiarid prairie region.

Rotational grazing increases purple prairie clover frequency in the rangeland plant communities under semi-arid environment

Purple prairie clover (PPC, Dalea purpurea Vent.) is a grazing tolerant perennial legume with good nutritional quality and is widely distributed across North America. Deferred rotational grazing (DR) and continuous grazing (CG) are the most widespread grazing systems on North American grasslands. We conducted a 10 yr grazing study to assess the effects of environmental factors and grazing on the frequency of PPC in plant communities. The results showed that the frequency of PPC decreased and then increased with increasing precipitation under CG (P < 0.05), while there was no significant change under DR (P > 0.05). Meanwhile, PPC frequency increased with temperature under DR (P < 0.05), but did not change under CG (P > 0.05). Both grazing systems and the number of grazing years had a significant effect on PPC frequency (P < 0.05), and there is no interaction between those two factors (P > 0.05). We found that from 2011 to 2020, the growth rate of PPC population is 18.24% and 11.69% per year under DR and CG grazing, respectively. Moreover, after 10 yr of grazing, the PPC increase in DR was 22.86% higher than that of CG. Thus, selecting the DR grazing system can increase PPC and is an effective practice for coping with environmental changes.

Dalea scandens (low prairie clover)

This datasheet on Dalea scandens covers Identity, Overview, Distribution, Dispersal, Biology & Ecology, Environmental Requirements, Impacts, Uses, Prevention/Control, Further Information.

Composition and Protein Precipitation Capacity of Condensed Tannins in Purple Prairie Clover (Dalea purpurea Vent.).

This study aimed to determine the concentration and composition of condensed tannins (CT) in different tissues of purple prairie clover (PPC; Dalea purpurea Vent.) at different maturities and to determine their protein-precipitating capacity. The compositions of CT were elucidated after thiolysis with benzyl mercaptan followed by high-performance liquid-chromatography (HPLC) and 1H–13C heteronuclear single quantum coherence (HSQC) NMR spectroscopy. The results indicated that PPC flowering heads contained the highest CT concentration. Purple prairie clover CT consisted mainly of epicatechin (EC) and epigallocatechin (EGC) subunits. CT in the leaves were composed of more EC and less EGC than CT in stems and flowering heads at both the early flowering (EF) and late flowering (LF) head stages. The mean degree of polymerization was the highest for CT in stems and increased with maturity. CT isolated from PPC leaves at the early flowering head stage exhibited the greatest biological activity in terms of protein precipitation. Overall, the CT in PPC were predominantly procyanidins and the concentration and composition varied among the plant tissues and with maturity.

Conserving purple prairie clover (Dalea purpurea Vent.) as hay and silage had little effect on the efficacy of condensed tannins in modulating ruminal fermentation in vitro.

The objective of this study was to determine the effects of forage conservation method and condensed tannins (CT) in conserved forage on rumen fermentation. Purple prairie clover (PPC; Dalea purpurea Vent.) containing 84.5 g kg-1 dry matter (DM) of CT was harvested at full flower and preserved as freeze-dried green chop (F), hay (H) or silage (S). Batch culture incubations were conducted using conserved forages as a substrate and treatments were arranged as 3 × 2 factorial design of forage type (F, H and S) with or without polyethylene glycol (PEG). PEG was used to isolate the effects of CT on fermentation. Incubation was repeated twice with quadruplicate vials for each treatment in each incubation. 15 N-labelled ammonium sulfate was used as microbial N marker and headspace gas was sampled to determine methane production. Concentrations of neutral detergent fiber (NDF) and acid detergent fiber were lower (P < 0.01) in F than in H or S. Ensiling decreased (P < 0.001) total phenolics and extractable CT, but had no effect on total CT, whereas none of these phenolic fractions were altered in H. Hay and silage had lower (P < 0.01) true DM disappearance (TDMD) and NDF disappearance (NDFD) than F. Inclusion of PEG did not affect TDMD or NDFD after 8, 24 or 72 h of incubation. Productions of total gas, methane and total volatile fatty acid and the rate of gas production (c) were also similar, but ammonia was higher (P < 0.05) and microbial N was lower (P < 0.05) with than without PEG after 72 h of incubation. After 72 h, a lower (P < 0.001) proportion of acetate but higher (P < 0.05) proportion of propionate was noted with S, resulting in a lower (P < 0.001) acetate:propionate ratio as compared to F or H after 8 h of incubation. Condensed tannins in PPC decreased protein degradation in vitro, but had minimal effects on overall rumen fermentation, and conservation of PPC as hay or silage had little effect on the efficacy of CT in modulating rumen fermentation. © 2020 Her Majesty the Queen in Right of Canada. Journal of The Science of Food and Agriculture © 2020 Society of Chemical Industry.

Activity of Bacteriophage and Complex Tannins against Biofilm-Forming Shiga Toxin-Producing Escherichia coli from Canada and South Africa.

Bacteriophages, natural killers of bacteria, and plant secondary metabolites, such as condensed tannins, are potential agents for the control of foodborne pathogens. The first objective of this study evaluated the efficacy of a bacteriophage SA21RB in reducing pre-formed biofilms on stainless-steel produced by two Shiga toxin-producing Escherichia coli (STEC) strains, one from South Africa and the other from Canada. The second objective examined the anti-bacterial and anti-biofilm activity of condensed tannin (CT) from purple prairie clover and phlorotannins (PT) from brown seaweed against these strains. For 24-h-old biofilms, (O113:H21; 6.2 log10 colony-forming units per square centimeter (CFU/cm2) and O154:H10; 5.4 log10 CFU/cm2), 3 h of exposure to phage (1013 plaque-forming units per milliliter (PFU/mL)) reduced (p ≤ 0.05) the number of viable cells attached to stainless-steel coupons by 2.5 and 2.1 log10 CFU/cm2 for O113:H21 and O154:H10, respectively. However, as biofilms matured, the ability of phage to control biofilm formation declined. In biofilms formed for 72 h (O113:H21; 5.4 log10 CFU/cm2 and O154:H10; 7 log10 CFU/cm2), reductions after the same duration of phage treatment were only 0.9 and 1.3 log10 CFU/cm2 for O113:H21 and O154:H10, respectively. Initial screening of CT and PT for anti-bacterial activity by a microplate assay indicated that both STEC strains were less sensitive (p ≤ 0.05) to CT than PT over a concentration range of 25–400 µg/mL. Based on the lower activity of CT (25–400 µg/mL), they were not further examined. Accordingly, PT (50 µg/mL) inhibited (p ≤ 0.05) biofilm formation for up to 24 h of incubation at 22 °C, but this inhibition progressively declined over 72 h for both O154:H10 and O113:H21. Scanning electron microscopy revealed that both SA21RB and PT eliminated 24 h biofilms, but that both strains were able to adhere and form biofilms on stainless-steel coupons at longer incubation times. These findings revealed that phage SA21RB is more effective at disrupting 24 than 72 h biofilms and that PT were able to inhibit biofilm formation of both E. coli O154:H10 and O113:H21 for up to 24 h.

Effects of inclusion of purple prairie clover (Dalea purpurea Vent.) with native cool-season grasses on in vitro fermentation and in situ digestibility of mixed forages

BackgroundIncorporation of legume species into native North American pastures is considered an effective method to increase native pasture productivity and improve the nutritive value of forage. This study evaluated the effects of inclusion of purple prairie clover (PPC, Dalea purpurea Vent.), a native legume forage, with native cool-season grasses on the in vitro fermentation and in situ digestibility of mixed forages.MethodsWhole plant PPC and mixtures of cool-season grasses were harvested when the PPC reached the vegetative (VEG), full flower (FL) and seedpod (SP) stages, and were combined in ratios (DM basis) of 0:100, 25:75, 50:50, 75:25 and 100:0 at each maturity. In vitro ruminal incubations using these mixtures were conducted for 48 h to determine gas production (GP), in vitro DM disappearance (IVDMD), total volatile fatty acids (VFA) and ammonia-N production. Mixtures of forages harvested when the PPC reached the FL stage and 50:50 mixture of forages harvested at VEG, FL and SP stages were incubated in the rumen of three heifers for 0, 2, 6, 12, 24, 48, 72 and 96 h to determine in situ degradabilities of DM, neutral detergent fibre (aNDF) and crude protein (CP).ResultsContents of aNDF and ADF increased (P < 0.01), while CP decreased (P < 0.001) as PPC matured. Concentrations of extractable condensed tannins in PPC ranked as FL > VEG > SP (P < 0.05). Regardless of PPC proportions in the mixture, GP decreased (P < 0.05) with increasing PPC maturity. Increasing PPC proportions linearly increased (P < 0.001) GP, IVDMD and total VFA at VEG, but linearly decreased (P < 0.001) them at SP. Irrespective of PPC maturity, ammonia-N production linearly increased (P < 0.01) with increasing proportions of PPC and the concentration was higher (P < 0.05) at VEG than at FL and SP stages. Increasing proportion of PPC at either maturity linearly increased (P < 0.001) molar percentage of acetate (A) and branched-chain VFA, but linearly decreased (P < 0.001) molar percentage of propionate (P), resulting in a linearly increase (P < 0.001) in the A:P ratio. Increasing FL PPC in the mixture linearly and quadratically (P < 0.01) increased a (soluble fraction), but linearly and quadratically decreased (P < 0.01) b (potentially degradable fraction) for DM and aNDF, resulting in linear (P < 0.05) and quadratic (P < 0.01) increases in DM and aNDF maximum potential degradabilities (a + b). Effective degradabilities of DM and aNDF were also linearly and quadratically increased (P < 0.05), and CP was quadratically increased (P < 0.05) with increasing FL PPC, with the greatest effective degradability being observed with ratios between 50:50 and 75:25. Ruminal maximum potential degradabilities of DM and aNDF decreased (P < 0.001) as the forage matured. Effective degradability of DM ranked as VEG > FL > SP (P < 0.001), whereas the effective degradability of aNDF was similar between VEG and FL and both were greater (P < 0.01) than SP.ConclusionsInclusion of vegetative PPC in a mixed forage diet resulted in the greatest digestibility and incorporation of PPC before seedpod stage with native grasses had a positive effect on ruminal fermentation. Effects of PPC on ruminal digestion depend on both the stage of maturity and its proportion in mixed legume-grass pastures. Pastures containing 50% of PPC in full flower stage would likely provide the greatest quality diet to grazing ruminants subject to potential animal selectivity.

PSVII-9 Agronomic characteristics and nutrient composition of purple prairie clover grown under irrigated and dryland conditions

Abstract Dry matter (DM) yield, nutrient composition, and in vitro digestibility of three populations (Common, AC Lamour, Bismarck) of purple prairie clover (PPC; Dalea purpurea Vent.) were determined in a 3-year study. Test plots of the populations were established in the 1st year under irrigation and dryland and whole plants were harvested at vegetative, full flower and late flower stages for determination of DM yield and nutritional characteristics in the 2nd and 3rd year. Only one cut per season was achieved for all populations under both growing conditions. The DM yield was similar among the three populations but irrigated land yielded higher (P &amp;lt; 0.01) DM than dryland in both years. The average DM yields (kg/ha; mean±SD) at the vegetative, full flower and late flower stages were 4739±1431, 4988±1547 and 6715±1580 under irrigation and 1423±479, 2014±348 and 2297±942 under dryland. Nutrient composition (organic matter, protein, neutral and acid detergent fibres and minerals) was similar among the three populations. Protein content was higher (P &amp;lt; 0.01) but neutral and acid detergent fibre content was lower (P &amp;lt; 0.05) in plants grown under irrigation than on dryland. Condensed tannin concentration was higher (P &amp;lt; 0.05) in plants grown under dryland than under irrigation. In vitro organic matter digestibility was higher (P &amp;lt; 0.05) for PPC grown under irrigation than on dryland. The PPC was readily established on both dry and irrigated land with comparable nutrient content to that of alfalfa and sainfoin under the similar growing conditions. Purple prairie clover has potential as an alternative legume forage, but its yearly yield is substantially lower than conventional legume forages.

Purple prairie clover seed viability and germinability after passing through the digestive tracts of yearling steers

Endozoochory by cattle has been considered an important method for population self-regeneration; however, the effects of cattle digestive tracts on the viability and germinability of purple prairie clover (Dalea purpurea Vent.), a native North American species, remain understudied. The experiment was conducted at the Agriculture and Agri-Food Canada Swift Current Research and Development Centre in the semiarid prairie of western Canada. Purple prairie clover seeds extracted from cattle dung pats were tested for germination and compared with uningested and scarified seeds from the same paddock. The germination percentage (within 200 d) of the ingested seeds was 16.5% ± 0.8%, two times higher after passing through digestive tracts than uningested seeds (8.3% ± 1.2%), while 76.6% ± 1.5% of ingested seeds remained dormant. As many as 92.4% ± 0.9% of purple prairie clover seeds survived digestion due to their high hard seed rate (90.5% ± 1.0%), which was lower than the uningested seeds by 6.9%. Therefore, cattle dispersing purple prairie clover seeds with high viability and germinability is a low-cost method to increase and rejuvenate purple prairie clover for late-season grazing pastures.

Dryland seedling emergence of basalt milkvetch (Astragalus filipes) and western prairie clover (Dalea ornata) under different planting seasons and seed treatments

Dryland seedling emergence of basalt milkvetch (<i>Astragalus filipes</i>) and western prairie clover (<i>Dalea ornata</i>) under different planting seasons and seed treatments

PSXI-26 Effects of condensed tannins in purple prairie and white prairie clover on ruminal fermentation and methane production in vitro.

It has been reported that condensed tannins (CT) from some forages decreases methane production. Purple prairie clover (PPC; Dalea purpurea Vent.) and white prairie clove (WPC; D. candida Michx. ex Willd) are native legumes adapted to the North American prairie and contain high concentration of CT. The objective of this study was to assess the effects of CT in PPC and WPC on ruminal fermentation and methane production. Whole-crop PPC and WPC were harvested at full flower stage and divided into two equal portions. One portion was freeze-dried and the other was sun-cured. Batch culture incubations were conducted using conserved forages as a substrate with and without inclusion of polyethylene glycol (PEG), which inactivates CT. Each incubation was repeated twice with two fermentation vials for each treatment in each run of the incubation. Concentration of CT (g/kg DM) in freeze-dried and sun-cured PPC and WPC were 90.5 ± 16.91, 88.1 ± 2.53, 62.8 ± 2.41 and 58.1 ± 2.82 respectively. Inclusion of PEG increased (Pin vitro DM disappearance (IVDMD), total gas production (GP) and ammonia concentration with PPC, regardless of conservation method. Freeze-dried PPC had greater (P<0.01) IVDMD and GP, but lower (P<0.01) ammonia concentration than sun-cured PPC. However, with WPC, no difference was observed in IVDMD or GP between the freeze-dried and sun-cured samples with or without PEG. Similar to PPC, addition of PEG also increased (P<0.05) ammonia concentration when WPC was incubated. Methane production was similar between the two forages and addition of PEG did not affect methane production from either forage. The greater effects of PEG on IVDMD, GP and ammonia production for PPC than for WPC is likely due to the higher concentration of CT in PPC than WPC. The results indicated that CT in PPC and WPC had no effect on ruminal methane production despite their high concentrations in these forages. Key Words:

PSVIII-21 Effect of inclusion of purple prairie clover with native cool-season grasses on in situ digestibility of mixed forage.

PSVIII-21 Effect of inclusion of purple prairie clover with native cool-season grasses on in situ digestibility of mixed forage.

Mortality and Flowering of Great Basin Perennial Forbs After Experimental Burning: Implications for Wild Bees

The fates of native bee communities in the Great Basin sagebrush steppe are linked with the susceptibilities of their floral hosts to increasingly frequent wildfires. Postfire survival and subsequent flowering of six prevalent perennial wildflowers representing five families were quantified across a range of realistic fire severities created using a calibrated propane burn barrel. Five burn prescriptions of varying intensity and duration were applied to cultivated rows of basalt milkvetch (Astragalus filipes Torr. ex A. Gray), Blue Mountain prairie clover (Dalea ornata Eaton & J. Wright), sulphur-flower buckwheat (Eriogonum umbellatum Torr.), fernleaf biscuitroot (Lomatium dissectum Nutt.), blue penstemon (Penstemon cyaneus Pennell), and gooseberryleaf globemallow (Sphaeralcea grossularifolia Hook. & Arn.). Overall differences in their fire sensitivities were maximal at peak fire severity, ranging from 80% survival (L. dissectum) to complete mortality (E. umbellatum and P. cyaneus). Although A. filipes survived well (85%), half of the 95 burn survivors then failed to flower the year after burning. The postfire fate of plant-pollinator interactions is a function of the bees’ nesting habits, their floral host’s sensitivity to a given burn intensity (both in terms of survival and flowering), and the reproductive interdependence of bee and floral host (taxonomic specialists vs. generalists).

Agro-morphology and forage nutritive value of white prairie clover [Dalea candida(Michx.) Willd.] populations native to the Canadian prairies

White prairie clover [Dalea candida (Michx.) Willd.] is native to the dry prairies and hillsides of the Northern Great Plains. A study was initiated in 2012 with six white prairie clover populations collected from the Canadian Prairies. Plant growth characteristics, forage biomass, seed yield, and forage nutritive values were evaluated using a randomized complete block design in a field near Swift Current, SK. Three populations from Argyle, Carlowrie, and Big Grass Marsh (NCP588) in Manitoba displayed erect-type growth while those from Douglas Provincial Park and Stewart Valley in Saskatchewan and Writing on Stone Provincial Park in Alberta exhibited prostrate growth. The populations did not differ for mean biomass yield (79–104 g plant−1, p = 0.54) and mean seed yield (6.6–9.1 g plant−1, p = 0.69); however, they differed for bloom stage nutritional parameters such as acid detergent fibre (25%–30%, p = 0.04), neutral detergent fibre (34%–41%, p &lt; 0.01), crude proteins (15%–18%, p &lt; 0.01), phosphorus (0.24%–0.29%, p = 0.02), and iron content (144–360 ppm, p = 0.01). To our knowledge, this is the first report of comparative phenotypic, nutritional, and propagation study of native white prairie clover populations of Canada. The constraints and opportunities for successful domestication of white prairie clover as a forage crop are discussed.

Lessons from Butterflies of the Black Belt Prairie: The Southern Dogface as an Indicator of Prairie Remnants

Of all terrestrial ecosystems in North America, grasslands are the most threatened. With continued threats and increased fragmentation of North American prairies, there is a need for proper identification of the remaining functional prairie remnant patches. In this study, we propose the Southern Dogface butterfly, Zerene cesonia, may serve as an indicator for identifying functional prairie remnant patches. To formally test for indicator status we focus on the critically imperiled Black Belt prairie. We investigated the relationship between Pierid, sulphur, butterflies, prairie host plant distributions, and environmental conditions (soil pH and area) across several grassland sites in the Black Belt region of Mississippi. The Black Belt is a grassland association that is understudied and poorly known outside of its local region. The Black Belt system hosts many species of flora and fauna either native or disjunct from the Great Plains. One such species is Z. cesonia, which is observed to be limited in its distribution to prairie grasslands. The results from field observations showed that Z. cesonia is clear indicator of prairie remnant patches. The results from laboratory oviposition experiments show Z. cesonia has a strong preference for prairie clover, (Dalea purpurea). Collectively, these results suggest Z. cesonia has an association with prairie remnants that may be driven by its preference of prairie clover as its larval host. Broadly, this study provides an example of how butterfly communities and their environmental interactions can be used to assess grassland function and conservation efforts.

Do Abrasion- or Temperature-Based Techniques More Effectively Relieve Physical Dormancy in Seeds of Cold Desert Perennials?

Seed dormancy can present a significant barrier to restoration outcomes in dryland systems. Physical and combinational (physical + physiological) dormancy are prevalent among seeds of many herbaceous perennials used in restoration of drylands throughout the western United States. Although many techniques designed to alleviate these dormancy traits exist, their efficacy is species specific, may result in embryo damage, and may have limited large-scale application. To identify the most effective means of dormancy alleviation with the potential to be used on an operational scale, we examined the effects of 16 temperature-based techniques (altering temperature and duration of wet heat, freezing and wet heat, and freeze-thaw cycles) and 6 abrasion-based techniques (altering pneumatic scarification length or using a single duration of manual scarification) on the enhancement of seed permeability among two physically dormant (western prairie clover [Dalea ornata {Douglas} Eaton & Wright] and Munro’s globemallow [Sphaeralcea munroana {Douglas} Spach]) and two combinationally dormant species (basalt milkvetch [Astragalus filipes Torr. ex A. Gray] and longspur lupine [Lupinus arbustus {Douglas} ex Lindl.]). We first assessed seed imbibition following exposure to all temperature- and abrasion-based techniques to identify those most successful at promoting seed permeability and then evaluated the effectiveness of those techniques through a series of germination experiments. For combinationally dormant species, we also tested whether exposure to GA3 enhanced germination. Abrasion-based techniques were more effective than temperature-based techniques at improving water uptake across all species. Pneumatic scarification significantly improved germination, but optimal treatment durations were species specific. GA3 did not enhance germination under the tested conditions. We conclude that pneumatic scarification is a fast, safe, and effective method for alleviating physical seed dormancy with a potential to be scaled up for operational use in restoration.

Characterization of Condensed Tannins from Purple Prairie Clover (Dalea purpurea Vent.) Conserved as either Freeze-Dried Forage, Sun-Cured Hay or Silage.

Conservation methods have been shown to affect forage nutrient composition and value, but little information is available about the effect of forage conservation on plant condensed tannins (CT). The objective of this study was to assess the effects of conservation method on the concentration, chemical composition and biological activity of CT. Whole-plant purple prairie clover (PPC, Dalea purpurea Vent.) was harvested at full flower and conserved as freeze-dried forage (FD), hay (HAY) or silage (SIL). Concentration of CT in conserved PPC was determined by the butanol-HCl-acetone method. Structural composition, protein-precipitation capacity and anti-bacterial activity of CT isolated from conserved forage were determined by in situ thiolytic degradation followed by HPLC-MS analysis, a protein precipitation assay using bovine serum albumin and ribulose 1,5-disphosphate carboxylase as model proteins and by an Escherichia coli (E. coli) growth test, respectively. Conservation method had no effect on concentration of total CT, but ensiling decreased (p < 0.001) extractable CT and increased (p < 0.001) protein- and fiber-bound CT. In contrast, hay-making only increased (p < 0.01) protein-bound CT. Regardless of conservation method, epigallocatechin (EGC), catechin (C) and epicatechin (EC) were the major flavan-3-ol units, and gallocatechin (GC) was absent from both terminal and extension units of PPC CT. The SIL CT had the lowest (p < 0.001) EGC, but the highest (p < 0.01) EC in the extension units. Similarly, SIL CT exhibited a lower (p < 0.001) mean degree of polymerization (mDP), but higher (p < 0.001) procyanidins (PC) than FD or HAY CT. The protein-precipitating capacity of CT in conserved PPC ranked (p < 0.001) as FD > HAY > SIL. E. coli growth n M9 medium was inhibited by 25–100 µg/mL of CT isolated from FD, HAY and SIL (p < 0.05), but preservation method had no effect on the ability of CT to inhibit bacterial growth. The results demonstrated that ensiling decreased the extractability and protein-precipitating capacity of CT by increasing the proportions of PC. Purple prairie clover conserved as hay retained more biologically active CT than if it was conserved as silage.