Dalea Purpurea 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.

Rare legumes are missing mutualists, but herbivory and environmental filtering are more important determinants of reintroduction success

Soil microbial mutualists like rhizobia bacteria can promote the establishment of rare, late‐successional legumes. Despite restoration efforts, these mutualists are often absent in the microbiome. Therefore, restoring this mutualism by directly inoculating rare legumes with rhizobia mutualists may increase plant establishment. We inoculated seedlings of Amorpha canescens, Dalea purpurea, and Lespedeza capitata with three strains of species‐specific rhizobia each to investigate how this mutualism would promote growth in the field and in the greenhouse. Because many herbaceous plants are vulnerable to herbivory, we used exclosures for half of our field transplantations to prevent mammalian herbivory. We did not find that rhizobia bacteria directly promoted the growth of our legumes in the field but rather that herbivory and environmental conditions overwhelmed the effects of the rhizobia. Of the plants transplanted, only 17.78% of 180 survived to the end of the growing season, all of which were protected from herbivory. Survival at the end of the growing season was also greater in the northern, drier end of the field site. In the second growing season, plants were more likely to survive in the exclosure treatment, while only four recovered in the open treatment. In the greenhouse, we found increased nodulation with inoculations, supporting the hypothesis that species‐specific mutualists are absent from restoration sites. Though several recent studies have shown that restoring mutualistic interactions has the potential to dramatically improve the outcomes of ecological restoration, our results show that protecting rare species from herbivory after transplantation might achieve greater gains in establishment.

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℃ .

Seeding and transplanting native forbs on reclamation sites in Alberta, Canada

A growing number of industrial disturbances are reclaimed with native grass species, although use of many native forbs in reclamation is limited due to low availability, high expense, poor germination, and lack of information on how to successfully establish them. Therefore, a study was conducted to assess the performance (establishment, growth, and survival) of native forbs (10 species by seeding and 12 species by transplanting) on disturbed sites planted in different seasons (spring and fall) and subjected to different types of vegetation management (mowed and unmowed). All seeded forb species established successfully, although density of most of the native forbs was very low (<20 stems/plot). Transplanted forb species established well, with 65% of seedlings surviving two growing seasons. Establishment and survival of seeded and transplanted native forbs were associated with plant competition, where forbs established well with annual weeds and less successfully with perennial weeds. Both spring seeding and transplanting increased forb establishment; and seeding and transplanting in fall versus spring produced more seed. Mowing generally had limited effects on forbs. Of the seeded species, Vicia americana, Achillea millefolium, and Ratibida columnifera consistently had the highest densities across treatments, whereas spring transplanting increased establishment of Anemone cylindrica, Gaillardia aristata, Geum triflorum, Monarda fistulosa, and Dalea purpurea. Spring‐transplanted forbs spread over a larger area than fall‐transplanted forbs. In most cases, seeding and transplanting native forbs in the spring can be more effective than in fall to reclaim disturbed sites if land management practices are used to control perennial weeds.

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.

Response of Common Wildflower Species to Postemergence Herbicides

Wildflowers attract wildlife, increase pollinator habitat, and enhance the aesthetic value of the landscape. Wildflower establishment is increasingly part of an effort to reduce maintained turfgrass on golf courses, lawns, and other maintained environments. Weed competition decreases wildflower establishment and results in poor long-term stands. Research was conducted in a controlled environment to investigate the tolerance of wildflower species to common postemergence herbicides. Wildflower species included California poppy (Eschscholzia californica Cham.), common sunflower (Helianthus annuus L.), cornflower (Centaurea cyanus L.), garden coreopsis (Coreopsis lanceolata L.), partridge pea [Chamaecrista fasciculata (Michx.) Greene], plains coreopsis (Coreopsis tinctoria Nutt.), purple coneflower [Echinacea purpurea (L.) Moench], rosering gaillardia (Gaillardia pulchella Foug.), and violet prairie clover (Dalea purpurea Vent.). Herbicides evaluated were fluazifop at 0.28 kg⋅ha–1 a.i., mesotrione at 0.14 kg⋅ha–1 a.i., clopyralid at 0.29 kg⋅ha–1 a.i., bentazon at 0.56 kg⋅ha–1 a.i., halosulfuron at 0.053 kg⋅ha–1 a.i., and imazaquin at 0.42 kg⋅ha–1 a.i. An untreated check was included for comparison. Excessive damage (≥ 53% phytotoxicity) was observed on all wildflower species in response to clopyralid, except for California poppy. Fluazifop and bentazon were relatively safe (≤ 19% phytotoxicity, regardless of herbicide) on all wildflower species; however, bentazon resulted in ≥ 40% aboveground biomass reduction in several species. Common sunflower and garden coreopsis were susceptible to halosulfuron (37% and 73% phytotoxicity, respectively) and imazaquin (37% and 87% phytotoxicity, respectively), but on all other wildflower species, phytotoxicity was ≤ 18%. Although both halosulfuron and imazaquin only resulted in ≤ 18% phytotoxicity to purple coneflower, a 43% to 44% aboveground biomass reduction was recorded. Mesotrione was only safe on California poppy and cornflower (≤ 11% phytotoxicity and ≤ 24% aboveground biomass reduction). Results suggest high tolerance variability across herbicides and species considered, but may prompt new investigation of safety and utility within field and production scenarios.

A 6-yr evaluation of prescribed-fire timing on yearling cattle growth performance and plant community dynamics on native tallgrass prairie in the Kansas Flint Hills

Abstract A 6-yr experiment was conducted to determine the effects of prescribed-fire season on stocker cattle growth performance and rangeland plant community characteristics in the Kansas Flint Hills. Eighteen pastures were grouped by watershed and each watershed was randomly assigned to 1 of 3 prescribed-fire treatments: spring (11 April ± 5.7 d), summer (25 August ± 6.2 d), or autumn (2 October ± 9.0 d). All burns were applied prior to grazing in years 1, 2, 3, and 5; however, no burns were applied in year 4 because of unfavorable burn conditions. Over 5 consecutive grazing seasons, 1,939 yearling stocker calves (initial BW = 281 ± 58.9 kg) were grazed from May to August at a targeted stocking density of 280 kg live-weight + ha−1. Beginning in June of 2018 (pretreatment), a permanent 100-m transect was established in each pasture and was used to determine plant-species composition using a modified step-point method. Forage biomass accumulation and root carbohydrate concentrations of 4 native tallgrass plant species were also measured. All data were analyzed as a completely randomized design using a mixed model. Average daily gain (ADG) was 0.05 to 0.07 kg greater (P = 0.02) for calves grazing spring-burned pastures compared with calves grazing summer- or autumn-burned pastures; however, ADG did not differ (P ≥ 0.55) between calves assigned to the summer or autumn prescribed-fire treatments. Basal cover of all graminoids and all forbs did not differ (P ≥ 0.30) among prescribed-fire treatments; however, basal cover of C3 grasses tended (P = 0.06) to be greater while basal cover of C4 grasses tended (P = 0.08) to be less in autumn-burned pastures compared with spring-burned pastures. Forage biomass accumulation did not differ (P = 0.58) among treatments. In addition, root starch or root water-soluble carbohydrate concentrations in big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), Indiangrass (Sorghastrum nutans), or purple prairieclover (Dalea purpurea) did not differ (P ≥ 0.26) among prescribed-fire treatments. Overall, we interpreted these data to suggest that prescribed-fire timing had small influences on yearling stocker cattle growth performance and rangeland plant composition but did not influence forage biomass accumulation or root carbohydrate concentrations of key native tallgrass plant species in the Kansas Flint Hills.

Traffic patterns, more than adjacent land use, influence element content of roadside forbs for insect pollinators

Abstract Roadsides are targeted for restoration of pollinator‐friendly plants. Yet, roads are sources of macronutrient, micronutrient and heavy metal pollution that may contaminate roadside plants. Adjacent landscape features such as railroads and agriculture provide additional macronutrient and heavy metal pollution that may exacerbate traffic effects. However, we lack perspective on how roads combine with rural landscape features to influence nutrition of roadside plants, which could have implications for pollinator health. We surveyed roadsides across Minnesota, USA and measured foliar levels of dietary macronutrients (nitrogen, phosphorous and potassium), a micronutrient (sodium) and metals (iron, zinc, copper, chromium, nickel, lead, aluminium and cadmium) in six abundant roadside forb species used by insect pollinators: Asclepias syriaca, Dalea purpurea, Monarda fistulosa, Ratibida pinnata, Solidago spp. and Trifolium pratense. We aimed to determine (1) how road variables (traffic volume and distance from road) combine with adjacent land use (railroad and agriculture) to influence element content of roadside forbs and (2) whether some forb species show consistent differences in their accumulation of potentially toxic heavy metals, which could inform selection of species to plant along roadsides. We found that foliar concentrations of nine elements increased with greater traffic volume (nitrogen, phosphorous, iron, zinc, copper, chromium, nickel, lead and aluminium), and concentrations of six elements declined with distance from the road (nitrogen, phosphorous, potassium, iron, zinc and copper). Leaves collected adjacent to railroad had less phosphorous, potassium, iron, nickel and aluminium than leaves collected from sites not adjacent to railroad. Additionally, leaves collected from sites adjacent to agriculture had lower copper levels than leaves from sites without adjacent agriculture. We found no evidence that particular ford species along roadsides consistently rank higher than other species in their accumulation of heavy metals. Our results show that traffic alters more elements in roadside plants than does adjacent landscape context, alleviating concerns that landscape features exacerbate pollutant levels in roadside pollinator habitat. However, nutrient contamination of most roadside plants is unlikely to reach toxic levels for insect pollinators. This work is consistent with the positive conservation potential of low to moderate traffic roadsides for pollinators.

Interactive effects of biochar and N-fixing companion plants on growth and physiology of Acer saccharinum

The use of biochar with N-fixing species has been shown to enhance productivity of agricultural systems, both in N-fixing crops, as well as in mixed-species systems. Here we investigate the potential for the use of a granulated mixed conifer biochar and a sugar maple biochar in combination with N-fixing companion plants in an urban forestry context. A factorial greenhouse experiment compared growth responses in silver maple (Acer saccharinum L.) saplings planted with two biochar types as soil amendments, alone and in combination with two N-fixing plant companions (Trifolium repens L. and Dalea purpurea Vent.). Both biochar types enhanced tree growth; however, a maple feedstock biochar resulted in greater increases than a granulated conifer-feedstock biochar. N-fixing companion species also increased tree growth, although the faster-growing Trifolium reduced soil moisture content and reduced sapling growth in the absence of biochar. The highest tree growth performance and total N uptake was obtained with a combination of both biochar and N-fixing plants, with a ~30 % increase in biomass compared to controls for the granulated conifer biochar, and a ~55 % increase for the maple biochar. We conclude that biochar additions in combination with N-fixing companion species have considerable promise in an urban forestry context, but that optimization of the system in terms of biochar type and species combination is an important consideration.

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.

Can Native Plants Mitigate Climate-related Forage Dearth for Honey Bees (Hymenoptera: Apidae)?

Extreme weather events, like high temperatures and droughts, are predicted to become common with climate change, and may negatively impact plant growth. How honey bees (Apis mellifera L. [Hymenoptera: Apidae]) will respond to this challenge is unclear, especially when collecting pollen, their primary source of protein, lipids, and micro-nutrients. We explored this response with a data set from multiple research projects that measured pollen collected by honey bees during 2015–2017 in which above-average temperatures and a drought occurred in 2017. We summarized the abundance and diversity of pollen collected from July to September in replicated apiaries kept at commercial soybean and corn farms in Iowa, in the Midwestern USA. The most commonly collected pollen was from clover (Trifolium spp. [Fabales: Fabaceae]), which dramatically declined in absolute and relative abundance in July 2017 during a period of high temperatures and drought. Due to an apparent lack of clover, honey bees switched to the more drought-tolerant native species (e.g., Chamaecrista fasciculata [Michx.] Greene [Fabales: Fabaceae], Dalea purpurea Vent. [Fabales: Fabaceae], Solidago spp. [Asterales: Asteraceae]), and several species of Asteraceae. This was especially noticeable in August 2017 when C. fasciculata dominated (87%) and clover disappeared from bee-collected pollen. We discuss the potential implications of climate-induced forage dearth on honey bee nutritional health. We also compare these results to a growing body of literature on the use of native, perennial flowering plants found in Midwestern prairies for the conservation of beneficial insects. We discuss the potential for drought resistant-native plants to potentially promote resilience to climate change for the non-native, managed honey bee colonies in the United States.

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.

Effects of prescribed fire timing on grazing performance of yearling beef cattle, forage biomass accumulation, and plant community characteristics on native tallgrass prairie in the Kansas Flint Hills.

Recent research demonstrated that mid- or late-summer prescribed fires can be employed to manage sericea lespedeza (Lespedeza cuneata) infestations in the Kansas Flint Hills. The effects of prescribed fire applied during the growing season (i.e., August to October) on grazing performance of yearling cattle have not been evaluated. Native pastures (n = 18; 22 ± 4.0 ha) were grouped by watershed and assigned randomly to one of three prescribed-fire treatments: spring (7 April ± 2.1 d), summer (21 August ± 5.7 d), or autumn (2 October ± 9.9 d). Yearling beef cattle were grazed from May to August at a targeted stocking density of 280 kg live-weight/ha following prescribed-fire application. Forage biomass accumulations, soil cover, plant species composition, and root carbohydrate concentrations in four native plant species were evaluated. Total body weight (BW) gains and average daily gain were greater (P = 0.01) for cattle that grazed the spring and summer prescribed-fire treatments compared with those that grazed the autumn prescribed-fire treatment. As a result, final BW were greater (P = 0.04) in the spring and summer treatments than the autumn treatment. Conversely, forage biomass accumulations did not differ (P = 0.91) between fire regimes. Proportions of bare soil were greater (P < 0.01) in the spring treatment compared with the summer and autumn treatments, whereas proportions of litter on the soil surface were greater (P < 0.01) in summer- and autumn-burned pastures compared with spring-burned pastures. Total basal cover of graminoids and forbs did not differ (P ≤ 0.15) between prescribed fire treatments. Likewise, total basal cover of C3 or C4 perennial grasses did not differ (P ≥ 0.23) between prescribed-fire treatments. No treatment differences (P = 0.24) in root starch or root water-soluble carbohydrate concentrations in big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), Indiangrass (Sorghastrum nutans), or purple prairieclover (Dalea purpurea) were detected. These data were interpreted to suggest that summer or autumn prescribed fire can be applied without reducing forage biomass accumulations, root carbohydrate concentrations in key native plant species, or considerably altering native plant populations compared with conventional spring-season prescribed fire; however, summer prescribed fire could be favored over spring or autumn prescribed fire both to maintain stocker cattle growth performance and to achieve control over sericea lespedeza.

Introduction of four native legumes of the Canadian Prairies in monoculture and in mixtures with meadow bromegrass (Bromus riparius)

Many questions remain concerning the viability and productivity of seeding native legumes in the Canadian Prairies for forage production. Field research was conducted with four native legume species (Astragalus flexuosus, Dalea purpurea, Hedysarum boreale, and Vicia americana) to evaluate performance in Swift Current and Saskatoon, SK. The experimental design was a randomized complete block design with four replicates to evaluate legume–grass mixtures and monoculture performance, botanical composition, and effect of harvest dates (July and August) from 2016 to 2018. The native legume–grass mixtures performed differently at the sites, with greater foliar cover at Saskatoon but a greater proportion of legumes in mixtures at Swift Current. The mixtures had similar forage nutritive value as monoculture Bromus riparius, with legumes contributing 10% or less of the forage dry matter yield (DMY) at both sites. Astragalus flexuosus showed the greatest foliar cover and produced the greatest DMY in monoculture at both sites. Based on this study, native legumes would need to make up a larger proportion of forage dry matter yield to change the nutritional value of mixtures. In a subsequent seeding rate evaluation, the four legume species were planted at three seeding rates [300, 200, and 100 pure live seeds (PLS) per metre] and tested for DMY one year following establishment near Swift Current. Increasing seeding rates up to 300 PLS·m−1 corresponded with an increase in seedling density and foliar cover, but DMY was not affected. Additional research with A. flexuosus is needed to demonstrate its value as a forage.

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.

Habitat-scale heterogeneity maintains fungal endophyte diversity in two native prairie legumes

ABSTRACT The assembly of fungal endophyte communities within plants depends on the complex interactions of fungal taxa, their host plants, and the abiotic environment. Prairie plant communities provide a unique avenue to explore the interplay of biotic and abiotic factors affecting endophyte communities, since the historical distribution of prairies spans a broad range of temperature and precipitation, while the distances between small fragments of contemporary prairie communities may challenge the dispersal capabilities of these otherwise ubiquitous fungi. We sampled foliar fungal endophytes from two native prairie legumes, purple and white prairie clovers (Dalea purpurea and D. candida), in 17 remnant prairie sites across Minnesota in order to evaluate the relative contributions of abiotic factors, host species, and dispersal limitation to the diversity and structure of these communities. We found that similarity of communities was significantly associated with their location along a temperature and precipitation gradient, and we showed a distance-decay relationship that suggests dispersal limitations only over very large spatial scales. Although the effect of host species was small relative to these other factors, the two Dalea species maintained distinct communities within sites where they co-occur. Our results illustrate the capacity of many of these endophyte taxa to disperse over large distances and across heterogeneous biotic and abiotic environments and suggest that the interplay of biotic and abiotic factors maintains high diversity observed in endophyte communities.

Impact of Artificial Diet on Development and Coloration in Zerene Cesonia

The development of artificial diets for Lepidopteran species is instrumental for the study of natural biological variation in controlled laboratory conditions. In this study, we test the ability to rear Zerene cesonia, a pierid species, on artificial diets containing varying amounts of two plant species: Dalea purpurea and Trifolium pratense. We evaluate the quality of each diet based on survivorship, developmental timing, and analyses of larval and adult coloration. This study concludes that diets that include the preferred host plant, D. purpurea, are best for rearing Z. cesonia based on survivorship and the ability to recapitulate the natural color variation observed in the wild.

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.

Inoculation with remnant prairie soils increased the growth of three native prairie legumes but not necessarily their associations with beneficial soil microbes

Restoring the diversity of plant species found in remnant communities is a challenge for restoration practitioners, in part because many reintroduced plant species fail to establish in restored sites. Legumes establish particularly poorly, perhaps because they depend on two guilds of soil microbial mutualists, rhizobial bacteria and arbuscular mycorrhizal (AM) fungi, that may be absent from restored sites. We tested the effect of soil microorganisms from remnant and restored prairies on legume growth by inoculating seedlings of Lespedeza capitata, Amorpha canescens, and Dalea purpurea with soil from 10 restored prairies and 6 remnant (untilled) prairies from southwest Michigan. We generally found support for the hypothesis that restored prairie soils lack microbes that enhance prairie plant growth, although there was variation across species and mutualist guilds. All three legumes grew larger and two legumes (Lespedeza and Amorpha) produced more nodules when inoculated with soil from remnant prairies, suggesting that low quantity and/or quality of rhizobial partners may limit the establishment of those species in restored prairies. In contrast, no legume experienced greater root colonization by AM fungi in remnant prairie soils, suggesting equivalent quantity (but not necessarily quality) of fungal partners in remnant and restored prairie soils. We detected no evidence of spontaneous recovery of the community of beneficial soil microbes in restorations. These results suggest that the absence of rhizobia, a largely overlooked component of prairie soils, could play a strong role in limiting restored prairie diversity by hindering legume establishment. Active reintroduction of appropriate rhizobial strains could enhance prairie restoration outcomes.