Rudbeckia Hirta Research Articles

Life history and ecology of the endangered Poweshiek skipperling Oarisma poweshiek in Michigan prairie fens

Poweshiek skipperling (Oarisma poweshiek, Lepidoptera: Hesperiidae) has experienced a range-wide decline resulting in six reported extant sites. Critical knowledge gaps related to Poweshiek skipperling adult behavior, phenology, habitat structure, and potential larval host plants are limiting the ability to manage this federally endangered species. To address these information needs, we conducted extensive surveys in the last remaining stronghold of four extant prairie fens in Michigan. We used point transect surveys to collect data on plant structure, and Poweshiek skipperling behavior and detection. We estimated Poweshiek skipperling abundance and modeled the influence of local vegetation on Poweshiek skipperling presence/absence. We estimated the abundance of adult Poweshiek skipperling in Michigan prairie fens to be 231 (95% CI 160–332), further highlighting the imperiled status of this species. Presence of Poweshiek skipperling along our transects was negatively associated with obstructive vegetation and positively associated with the availability of the nectar source Dasiphora fruticosa. Our observation data indicated females nectared most frequently on D. fruticosa, whereas males nectared most often on Rudbeckia hirta. Across the field season we observed 7 oviposition events on four plant species (Muhlenbergia richardsonis, Muhlenbergia glomerata, Carex sterilis, and D. fruticosa), three of which had no previous documentation as a possible host plant. Results from this study can be used to evaluate management decisions and inform both in situ and ex situ conservation efforts. It is critical to continue monitoring remaining populations, not only to assess conservation efforts, but also to discern the patterns and processes influencing species extinction.

Determination of thrombolytic, antioxidant and analgesic activity of methanolic extracts of Rudbeckia hirta

Determination of thrombolytic, antioxidant and analgesic activity of methanolic extracts of Rudbeckia hirta

Use of Diatomaceous Earth as a Silica Supplement on Potted Ornamentals

The role of silica as a needed supplement in soilless media is gaining interest. This research studied the effects of diatomaceous earth as a supplement on growth and flower characteristics, physiology, and nutrient uptake in dahlia (Dahlia Cav. × hybrida ‘Dahlinova Montana’), black-eyed Susan (Rudbeckia hirta L. ‘Denver Daisy’), and daisy (Gerbera jamesonii L. ‘Festival Light Eye White Shades’). Plants were either well-watered at 10 centibars or water-stressed at 20 centibars. Silicon treatments included top-dressed at 20, 40, 60, and 80 g, or incorporated at 50, 100, 150, and 200 g, in Metro-Mix 360 media without silica plus a control and one treatment of new Metro-Mix 360 with silica already incorporated. Significant effects were seen from diatomaceous earth supplementation, irrigation, and interaction in all plants; growth and flower characteristics, leaf nutrient content, and tolerance to stress were improved by application of diatomaceous earth. An increase in leaf N, P, K, Mg, and Ca was observed for dahlia ‘Dahlinova Montana’ and black-eyed Susan ‘Denver Daisy’. Transpiration was maintained in all three species due to silica supplementation under water-stress. Metro-Mix with silica was similar to the Metro-mix without silica and equivalent to most treatments with supplemental silica for all three species.

Morpho-physiological and biochemical responses of four ornamental herbaceous species to water stress

Understanding of water-deficit responses of plants can lead to better establishment and management of water-conserving landscapes. Due to the importance of landscape plants and the need for water relations of field-grown herbaceous species, this study investigated morphological and biochemical responses of Malva sylvestris, Althea rosea, Callistephus chinensis and Rudbeckia hirta under water stress. The main plots were the four plant species and the subplots were irrigation levels of 25%, 50%, 75%, and 100% reference evapotranspiration (ET0). The results indicated that 75% ET0 irrigation treatment had no effect on the relative water content of Althea rosea and R. hirta. Althea rosea and R. hirta had the highest deficit-irrigation tolerance index for root length and root density in 25% ET0. Only A. rosea, exhibited no oxidative stress as reduced chlorophyll content under 75% ET0–50% ET0, and also under 50% ET0–25% ET0. Only in R. hirta, the ratio of chlorophyll a/b was linearly increased. Water stress had no effect on total soluble carbohydrates in C. chinensis, R. hirta and M. sylvestris. Moving from 75 to 25% ET0, R. hirta showed the lowest electrolyte leakage which was followed by A. rosea. Althea rosea and R. hirta displayed a drought-avoidance mechanism.

Effects of various irrigation regimes on water use efficiency and visual quality of some ornamental herbaceous plants in the field

Efficient use of water by selection of appropriate plant species is becoming increasingly important in semi-arid and arid regions to save scarce water resources. In this study, the effects of water deficit irrigation on physiological responses, water-use efficiency (WUE) and visual quality of four herbaceous ornamental species (Malva sylvestris, Althea rosea, Callistephus chinensis and Rudbeckia hirta) were investigated. The experiment was a split-plot treatment based on a randomized complete block design experiment with four irrigation levels (25%, 50%, 75%, and 100% reference evapotranspiration (ET0)) and four replications. Althaea rosea and Rudbeckia hirta showed dehydration avoidance by modifying their leaf shape, decreasing stomatal conductance and increasing Water Use Efficiency (WUEi). The lowest specific leaf area and highest root/shoot ratio were seen in Althaea rosea at 25% and 50% ET0, respectively. Malva sylvestris used a drought escape strategy by early flowering. In terms of landscape aesthetic values, Malva sylvestris performed well with a minimum of 75% ET0. Althaea rosea and Rudbeckia hirta were well-maintained with 25%–50 % ET0 irrigation levels. However, for an acceptable aesthetic landscape appearance, the minimum level of irrigation for Callistephus chinensis was 50% ET0. These results suggest that use of drought-tolerant spices such as Althaea rosea and Rudbeckia hirta can improve irrigation management and conserve aesthetic performance in urban landscapes.

Meeting seed demand for landscape-scale restoration sustainably: the influence of seed harvest intensity and site management

ABSTRACTNative seed is often collected en masse from remnant ecosystems to supply landscape-scale restoration. Successful large-scale restoration depends on sustained seed yields but also on donor population persistence. Native plants that reproduce solely by seed are especially sensitive to harvesting practices. We addressed the challenge of procuring sufficient seed from remnant sources to restore landscapes while also maintaining remnant populations of native plants. We evaluated: 1) the sustainability of seed harvest at varying intensities in Rudbeckia hirta, a seed-reliant plant; and 2) the contribution of fire in promoting sustainability of seed donor populations. We planted seedlings of R. hirta in a field experiment that manipulated management type (burned or unburned) and harvest intensity (0, 50%, or 100% seed removed), and measured changes in seedling recruitment and seed production among treatments. Moderate intensity harvest and burning did not significantly reduce seedling recruitment, but high intensity harvest with burning reduced recruitment by 95% compared to controls. Seed production nearly doubled in burned treatments. In unburned prairie, recruitment is negligible, and harvest intensity does not have an effect on recruitment. For harvest-sensitive prairie species, a strategy incorporating moderate intensity seed harvest with burning is most likely to provide seed for large-scale restoration sustainably.

Pollinator Habitat Establishment after Organic and No-till Seedbed Preparation Methods

Establishing on-farm pollinator habitat can mitigate native pollinator and pollination ecosystem service declines, and federal programs are available to provide technical and financial assistance to farmers interested in habitat installation. Although sufficient seedbed preparation to limit weed competition is thought to be the most important step toward achieving good pollinator habitat establishment, preparation recommendations vary and studies have not investigated seedbed preparation techniques in the context of the U.S. Department of Agriculture (USDA) Farm Bill programs for pollinator conservation. To address this, we assessed the effects of two seedbed preparation methods, conventional inversion tillage and no-till with herbicide, on wildflower establishment and weed competition during the first year after planting. Experiments were conducted in Blacksburg, VA, and were replicated in 2015 and 2016. In addition, we tracked seedbed preparation methods and pollinator habitat establishment on seven farms located on the Eastern Shore of Virginia and Maryland in 2016. The wildflower mix consisted of nine species of forbs and two species of grasses: the forbs were black-eyed Susan (Rudbeckia hirta L.), partridge pea [Chamaecrista fasciculata (Michx.) Greene], plains coreopsis (Coreopsis tinctoria Nutt.), lanceleaf coreopsis (Coreopsis lanceolata L.), purple coneflower [Echinacea purpurea (L.) Moench], narrowleaf mountain mint (Pycnanthemum tenuifolium Schrad.), wild bergamot (Monarda fistulosa L.), Maximilian sunflower (Helianthus maximiliani Schrad.), and showy tickseed [Bidens aristosa (Michx.) Britton] or Indian blanket (Gaillardia pulchella Foug.); the grasses were splitbeard bluestem (Andropogon ternarius Michx.) and little bluestem [Schizachyrium scoparium (Michx.) Nash]. In the experiments, wildflower establishment was greater after no-till with herbicide than after tillage preparation (2015: P = 0.09; 2016: P = 0.002). Predominating weed species varied by study, with more common lambsquarters (Chenopodium album L.) and hairy galinsoga [Galinsoga ciliata (Raf.) S.F. Blake] growth after tillage treatments, and more hairy vetch (Vicia villosa Roth) growth after no-till preparation. On-farm pollinator habitat establishment on the Eastern Shore was highly variable, but more wildflower forbs established after tillage-plus-herbicide than tillage-only seedbed preparations (P = 0.01). Across sites, we found a large degree of site-specific variation in wildflower establishment and predominant weed species.

Ornamental Asteraceae Species as New Sources of Secondary Metabolites

Abstract: Objective: This paper presents the results regarding the morphological characters, the content in total phenols, the metabolites profile and the antioxidant activity of outdoor cultivated Rudbeckia hirta var. Goldilocks and Tagetes erecta plants. Material and Methods: The plant material was represented by flower buds and fully bloomed inflorescences taken from Rudbeckia hirta var. Goldilocks and Tagetes erecta. Morphological assessment was carried using microscopy, while chemical assessment used thin layer chromatography (TLC) and UHPLC methods. The total phenolic content was established with Folin- Ciocalteu method. The antioxidant activity was evaluated with DPPH radical scavenging tests. The secondary metabolites were evaluated in two different nutritional statuses. Results: The results indicated that the studied ornamental Asteraceae species represent rich sources of phenols. However, the fertilization lowers the plant’s biosynthetic capacity for polyphenols for both Rudbeckia and Tagetes flowers. Thus, by fertilizing, the flowers of Tagetes lose components such as polyphenolic acids, modifying their spectrum. Regarding the antioxidant activity, Tagetes erecta showed a promising activity against free radicals. Conclusion: The concentration of plant secondary metabolites was found to be influenced by the nutritional status. Both species represent a good source for secondary metabolites, but their biological potential remains to be established. Key words: Rudbeckia, Tagetes, Secondary metabolites, Ornamental plants, Antioxidant activity.

Apparent Seed Digestibility and Germination of Seeds After Passage Through the Digestive System of Northern Bobwhite (Colinus virginianus)

Limited information is available regarding the digestibility or germination of seeds after passage through the digestive system of northern bobwhites (Colinus virginianus), especially of plants associated with the sand sagebrush (Artemisia filifolia)–mixed prairie community. Thus, our objectives were to determine the apparent digestibility of seeds of 45 plant species associated with the sand sagebrush–mixed prairie community and the germination of seeds before and after passage through the digestion system of bobwhites. Seeds of 12 of 45 species fed to bobwhites were found to pass through the digestive system intact. The apparent seed digestion pattern of the 12 plant species with incomplete digestion of seeds was legumes > forbs > grasses > shrubs. At the end of a 7-d germination period, the digestion of seeds by bobwhites reduced seed germination of alkali sacaton (Sporobolus airoides), black-eyed Susan (Rudbeckia hirta), and western yarrow (Achillea millefolium var. occidentalis) but increased the germination of white prairie clover (Dalea candida) seeds (P ≤ 0.05). However, the germination percentage of predigestion seeds of white prairie clover exceeded that of postdigestion seeds (P < 0.05) by the end of a 21-d germination period. Averaged across species, the 21-d seed germination of postdigestion seeds was lower than predigestion seeds (P < 0.05). Viable seeds found in feces are disseminated by quail onto the landscape. Plant species that have been lost from overgrazing or the application of herbicides might be reintroduced onto landscapes through dissemination by bobwhites via food plots, feeding stations, or both if the seeds are deposited onto a suitable germination substrate with suitable seed germination conditions.

Sowing density effects and patterns of colonization in a prairie restoration

AbstractA cost‐effective approach in plant restorations could be to increase sowing density for species known to be challenging to establish, while reducing sowing density for species that easily colonize on their own. Sowing need not occur evenly across the site for rapidly dispersing species. We explored these issues using a prairie restoration experiment on a high‐school campus with three treatments: plots sown only to grasses (G plots), to grasses and forbs (GF1), and to grasses and forbs with forbs sown at twice the density (GF2). In year 2, GF1 and GF2 plots had higher diversity than G plots, as expected, but GF2 treatments did not have twice the sown forb cover. However, high forb sowing density increased forb richness, probably by reducing stochastic factors in establishment. Cover of nonsown species was highest in G plots and lowest in GF2 plots, suggesting suppressive effects of native forbs on weedy species. Colonization of G plots by two sown forbs (Coreopsis tinctoria and Rudbeckia hirta) was apparent after 2.5 years, providing evidence that these species are self‐sustaining. Colonization was greater in edges than in the central areas of G plots. Through construction of establishment kernels, we infer that the mean establishment distance was shorter for R. hirta (6.7 m) compared to C. tinctoria (21.1 m). Our results lead us to advocate for restoration practices that consider not only seed sowing but also subsequent dispersal of sown species. Furthermore, we conclude that restoration research is particularly amenable for outdoor education and university‐high school collaborations.

Investigating the efficacy of white light-emitting diodes at regulating flowering of photoperiodic ornamental crops

Under natural short days (SDs), low-intensity lighting during the middle of a night (night interruption, NI) can control flowering of daylength-sensitive ornamentals. Red (R, 600-700 nm) and far-red (FR, 700-800 nm) radiation is primarily absorbed by phytochromes that mediate flowering, whereas blue (B, 400-500 nm) radiation typically has less photoperiodic relevance, at least at a low intensity. White (W) light-emitting diodes (LEDs) emit photons over a broad spectrum; however to our knowledge, their efficacy at regulating flowering has not been published. We investigated whether white LEDs controlled flowering of five long-day plants [calibrachoa (Calibrachoa × hybrida), coreopsis (Coreopsis grandiflora), petunia (Petunia × hybrida), rudbeckia (Rudbeckia hirta), and snapdragon (Antirrhinum majus)] and two SD plants [chrysanthemum (Chrysanthemum × morifolium) and marigold (Tagetes erecta)]. Plants were grown in a greenhouse at 20°C under 9-h SDs with or without 4-h NIs from R, B+R, cool-W, warm-W, or R+W+FR LEDs. Irradiance at plant canopy was adjusted to approximately 2 µmol m-2 s-1 between 400 and 800 nm. Compared with SD, all NIs similarly promoted flowering of calibrachoa and rudbeckia; however, only R+W+FR promoted flowering of snapdragon. NIs without FR radiation (i.e., R, B+R, cool-W, and warm-W) accelerated flowering of coreopsis and petunia, but flowering under R+W+FR was 11-16% earlier than under the other NIs. R+W+FR was less effective than the other NIs at inhibiting flowering of chrysanthemum and marigold. Cool-W and warm-W had similar effects on flowering and development of all crops. Plant height of calibrachoa, coreopsis, and marigold at flowering was greatest under R+W+FR; however, stem length of the other crops was similar under all NIs. We conclude that W LEDs inhibited flowering of SD plants and were as effective as R or R+W+FR radiation at promoting flowering of some, but not all, long-day plants.

Identification, transmission and genomic characterization of a new member of the family Caulimoviridae causing a flower distortion disease of Rudbeckia hirta

A disease of Rudbeckia hirta (Black-eyed Susan), characterized by severe flower deformation, was observed in Minnesota during 2010–2016. A previously undescribed virus species, named Rudbeckia flower distortion virus (RuFDV, family Caulimoviridae, genus unassigned), was determined to be the causal agent of the disease. Symptoms induced by RuFDV infection resemble those characteristic of phytoplasma-induced diseases, but no phytoplasmas were detected in RuFDV-infected R. hirta. The virus, and the disease were transmitted readily by mechanical inoculation and by the aphid Myzus persicae, but only to R. hirta. Virions of RuFDV are icosahedral, 42–45nm in diameter, and contain a circular 8222bp dsDNA genome containing seven open reading frames (ORFs). The ORFs 2–6 have 28–52% amino acid sequence identity to the movement protein (MP), coat protein (CP), aspartic protease (AP), reverse transcriptase (RT) and RNase H, and translational transactivator (TA) domains of known caulimoviruses. The two remaining ORFs (1 and 7) have no significant amino acid sequence similarity to known viruses. Although the RuFDV ORF 6 is significantly truncated relative to those of other known caulimoviruses, neither this nor the concomitant absence of characteristic virus-encoded cytoplasmic inclusion bodies appears to adversely affect aphid transmission of this virus. Phylogenetic analysis based on the sequence of the RT region revealed no close relationship to known members of the family Caulimoviridae. Based on sequence similarity, genome organization and phylogenetic relatedness, RuFDV appears to be distinct from any currently recognized taxonomic grouping in the family Caulimoviridae.

Moderate-intensity blue radiation can regulate flowering, but not extension growth, of several photoperiodic ornamental crops

Lighting that creates an effective phytochrome photoequilibrium at the end of the day (day extension) or during the middle of the night (night interruption) can regulate flowering of photoperiodic ornamentals grown under short days. In addition to phytochrome regulation, blue (B) radiation can elicit cryptochrome-mediated photoperiodic responses, such as flowering and stem growth. Although B radiation at a low intensity does not influence plant development, we postulated that it could regulate flowering at a higher intensity while acting as a plant growth regulator. We grew five long-day plants [calibrachoa (Calibrachoa×hybrida), coreopsis (Coreopsis grandiflora), petunia (Petunia×hybrida), rudbeckia (Rudbeckia hirta), and snapdragon (Antirrhinum majus)] and two short-day plants [chrysanthemum (Chrysanthemum×morifolium) and marigold (Tagetes erecta)] in a controlled-environment greenhouse under a 9-h short day with or without 5.5-h day-extension or 4-h night-interruption lighting from light-emitting diodes. B radiation was delivered at 0, 1 (low), 15, or 30 (moderate) μmolm−2s−1, with or without low red (R)+white+far-red (FR) radiation. Moderate B radiation created long days in all crops as effectively as low R+white+FR radiation. Flowering of calibrachoa and petunia, but not other crops, was 2–4d earlier when moderate B radiation was added to low R+white+FR radiation. At a sufficiently high intensity, B radiation possibly mediated these flowering responses through interactions of signaling molecules and multiple photoreceptors besides phytochromes. There were few or no morphological differences among flower-inducing treatments in most crops. We conclude that night-interruption lighting with moderate B radiation, alone and when added to low R and FR radiation, can regulate flowering, but does not inhibit extension growth, of a wide range of photoperiodic crops.

Evaluation of Pre- or Postharvest Application of Some Minerals and Organic Agents on the Growth, Flowering and Vase Life of Rudbeckia hirta, L.

&lt;p&gt;The experiments were carried out during 2014 and 2015 summer seasons at the greenhouses of the Experimental Farm of Faculty of Agriculture, Kafr El-Sheikh University. The experiments were conducted in two phases: First one (pre-harvest): &lt;em&gt;Rudbeckia hirta&lt;/em&gt; seedlings were transplanted during the first week of May to 30 cm diameter plastic pots filled with a soil mixture of clay and sand (1:1, v:v). Pots were divided in two equal groups, the first one, plants were foliar sprayed with one of the following:- Distilled water for the control treatment, CaCl&lt;sub&gt;2&lt;/sub&gt; (125, 250, 375 mg·L&lt;sup&gt;-1&lt;/sup&gt;), NiSO&lt;sub&gt;4&lt;/sub&gt; (30, 45, 60 mg·L&lt;sup&gt;-1&lt;/sup&gt;), CoCl&lt;sub&gt;2&lt;/sub&gt; (50, 75, 100 mg·L&lt;sup&gt;-1&lt;/sup&gt;), K&lt;sub&gt;2&lt;/sub&gt;SiO&lt;sub&gt;3&lt;/sub&gt; (100, 150, 200 mg·L&lt;sup&gt;-1&lt;/sup&gt;) and SA (100, 150, 200 mg·L&lt;sup&gt;-1&lt;/sup&gt;) at 60, 45, 30 and 15 days before harvest. The second group was without pre-harvest application assay (untreated plants).&lt;/p&gt;&lt;p&gt;Second phase (postharvest) was conducted in two different methods as follows: First method, flower stems resulted from each pre-harvest treatment were preserved in 250 mL graduated test tube filled with 200 mL of standard holding solution consists of sucrose (4%) + 8-Hydroxyquinoline citrate (250 mg·L&lt;sup&gt;-1&lt;/sup&gt;). The second method, flower stems resulted from plants without pre-harvest application preserved in holding solution consists of a constant sucrose (4%) and 8-Hydroxyquinoline citrate (250 mg·L&lt;sup&gt;-1&lt;/sup&gt;) beside one of the following additives: Distilled water for the control treatment, CaCl&lt;sub&gt;2&lt;/sub&gt; (125, 250, 375 mg·L&lt;sup&gt;-1&lt;/sup&gt;), NiSO&lt;sub&gt;4&lt;/sub&gt; (30, 45, 60 mg·L&lt;sup&gt;-1&lt;/sup&gt;), CoCl&lt;sub&gt;2&lt;/sub&gt; (50, 75, 100 mg·L&lt;sup&gt;-1&lt;/sup&gt;), K&lt;sub&gt;2&lt;/sub&gt;SiO&lt;sub&gt;3&lt;/sub&gt; (100, 150, 200 mg·L&lt;sup&gt;-1&lt;/sup&gt;) and Salicylic acid (100, 150, 200 mg·L&lt;sup&gt;-1&lt;/sup&gt;). Results showed that, pre harvest spraying plants with higher levels of K&lt;sub&gt;2&lt;/sub&gt;SiO&lt;sub&gt;3&lt;/sub&gt; or CaCl&lt;sub&gt;2&lt;/sub&gt; recorded the highest values for all plant vegetation characters. K&lt;sub&gt;2&lt;/sub&gt;SiO&lt;sub&gt;3&lt;/sub&gt; followed by SA excelled on others in most flowering aspects. At the post harvest stage, SA, K&lt;sub&gt;2&lt;/sub&gt;SiO&lt;sub&gt;3&lt;/sub&gt; and CaCl&lt;sub&gt;2&lt;/sub&gt; exchanged the excellence between them for most vase life measurements. Flowers resulted from plants that preharvest treated was better than those that did not preharvest treated.&lt;/p&gt;

M&M reports on animal feed pigments, cosmetic colrants & plastics masterbatch

The spectral quality of photoperiodic lighting can affect flowering of short-day plants (SDPs) and long-day plants (LDPs) differently. When delivered during the middle of the night (night interruption, NI), red (R; 600–700 nm) light alone can inhibit flowering of SDPs, whereas a combination of R and far-red (FR; 700–800 nm) light promotes flowering of some LDPs. However, whether or not low-intensity (≈1–2 μmol m−2 s−1) blue (B; 400–500 nm) light, when added to R and/or FR light, influences flowering has not been established. We investigated the effects of mixed B, R, and FR light on flowering of five SDPs [chrysanthemum (Chrysanthemum × morifolium), cosmos (Cosmos sulfureus), two cultivars of dahlia (Dahlia pinnata), and marigold (Tagetes erecta)] and two LDPs [dianthus (Dianthus chinensis) and rudbeckia (Rudbeckia hirta)]. Plants were grown in a greenhouse at a constant set point of 20 °C and received a truncated 9-h short day (SD) with or without 4-h NI lighting from incandescent (INC) lamps or white (W), B, B + R, B + FR, B + R + FR, or R + FR light-emitting diodes (LEDs). Each NI lighting treatment delivered a mean photon flux of 1.5 μmol m−2 s−1 between 400 and 800 nm at plant height. Blue light alone was not perceived as a long day by all SDPs and LDPs tested. For all SDPs, W LEDs inhibited flowering most effectively. B + R NI was as effective as W NI at creating a long day for all SDPs except chrysanthemum. B + FR NI inhibited flowering of marigold and dahlia ‘Leanne’, but not chrysanthemum or dahlia ‘Gallery Pablo’. For marigold, B + FR NI was less effective than other NI lighting treatments with R light. B + R + FR and R + FR NI similarly delayed flowering of all SDPs except dahlia ‘Gallery Pablo’. NI lighting treatments containing R light similarly promoted flowering of rudbeckia. We conclude that in at least the crops studied, low-intensity B light during the night does not influence flowering. In addition, W LEDs that emit little FR light are effective at creating long days for SDPs but only some LDPs.

Laesims studies of Echinacea purpurea, Rudbeckia hirta, and Helianthemum annus

Laser ablation electrospray ionization mass spectrometry has provided a nearly sample-preparation-free imaging technique that is well suited to biological tissues. While a number of studies have focused on its applications to animal tissues, fewer have used LAESIMS with plants. We present here an investigation into a plant commonly used as an herbal supplement or tea, Echinacea purpurea, and two other plants of the Heliantheae tribe: Rudbeckia hirta and Helianthemum annus. Fresh and dried samples were subjected to LAESIMS and we present the results here. The LC-MS spectra are also presented.

Native Plant Establishment on Georgia Roadsides

Invasive weeds are a costly problem on Georgia roadsides due to limited management options and a lack of competition from roadside grasses. The introduction of species native to Georgia could reduce maintenance costs and suppress invasive weeds on roadsides, however, limited research has been conducted with these species in this environment. Field experiments were conducted in Georgia to evaluate establishment of 29 species (12 grasses and 17 forbs) established in the fall and/or spring at two seeding rates. Blackeyed Susan (Rudbeckia hirta L.), swamp milkweed (Asclepias incarnata L.), and indiangrass [Sorghastrum nutans (L.) Nash] were the quickest to establish of all species, while blackeyed Susan, lanceleaf coreopsis (Coreopsis lanceolata L.), and wild bergamot (Monarda fistulosa L.) provided the greatest ground cover over the 12 mo experiment. At four of the five sites, up to four additional species of those evaluated established ≥20% ground cover in the spring seeding compared to fall. Species seeded in the spring also established faster during the first 4 mo after seeding. Overall, blackeyed Susan, indiangrass, lanceleaf coreopsis, swamp milkweed, and wild bergamot have the best potential, of the species tested, to establish under roadside conditions in Georgia.

An intermediate phytochrome photoequilibria from night-interruption lighting optimally promotes flowering of several long-day plants

Flowering of long-day (LD) plants is promoted by low-intensity (photoperiodic) lighting during an otherwise long night. Conventional lamps that emit a relatively low red (R; 600–700nm) to far-red (FR; 700–800nm) light ratio (e.g., incandescent lamps) create an intermediate phytochrome photoequilibria (PPE) and are sometimes more effective at promoting flowering of LD plants (LDP) than lamps that emit a higher R:FR (e.g., fluorescent lamps) and establish a higher PPE. Thus, we postulated that flowering of several LDPs would be increasingly promoted as the fraction of FR radiation increased relative to R light and the established PPE decreased. Rudbeckia (Rudbeckia hirta), snapdragon (Antirrhinum majus), Fuchsia (Fuchsia×hybrida), and three cultivars of Petunia (Petunia×hybrida) were grown at 20°C under a truncated 9-h ambient photoperiod with or without 4-h NI lighting by incandescent lamps or light-emitting diodes that emitted seven different R:FR and created estimated PPE from 0.16 to 0.89. For all three Petunia cultivars and snapdragon, flowering was earliest under an NI with an intermediate PPE and delayed under short days (SDs) or an NI that elicited the highest or lowest PPE. For Rudbeckia and Fuchsia, all NI treatments promoted flowering except for the highest PPE NI, which was perceived as an SD. There were relatively subtle effects of the NI treatments on extension growth except in Petunia, in which all three cultivars showed a quadratic response to the PPE under the NI treatments, where plants were tallest at flowering under intermediate PPE. We conclude that an NI that establishes an intermediate PPE optimally promotes flowering of a variety of LDPs. These results are not consistent with the established paradigm for how light quality regulates flowering of LDPs, particularly in Arabidopsis, suggesting that the paradigm is not necessarily applicable to plants outside of the Brassicaceae.

Low-intensity blue light in night-interruption lighting does not influence flowering of herbaceous ornamentals

The spectral quality of photoperiodic lighting can affect flowering of short-day plants (SDPs) and long-day plants (LDPs) differently. When delivered during the middle of the night (night interruption, NI), red (R; 600–700nm) light alone can inhibit flowering of SDPs, whereas a combination of R and far-red (FR; 700–800nm) light promotes flowering of some LDPs. However, whether or not low-intensity (≈1–2μmolm−2s−1) blue (B; 400–500nm) light, when added to R and/or FR light, influences flowering has not been established. We investigated the effects of mixed B, R, and FR light on flowering of five SDPs [chrysanthemum (Chrysanthemum×morifolium), cosmos (Cosmos sulfureus), two cultivars of dahlia (Dahlia pinnata), and marigold (Tagetes erecta)] and two LDPs [dianthus (Dianthus chinensis) and rudbeckia (Rudbeckia hirta)]. Plants were grown in a greenhouse at a constant set point of 20°C and received a truncated 9-h short day (SD) with or without 4-h NI lighting from incandescent (INC) lamps or white (W), B, B+R, B+FR, B+R+FR, or R+FR light-emitting diodes (LEDs). Each NI lighting treatment delivered a mean photon flux of 1.5μmolm−2s−1 between 400 and 800nm at plant height. Blue light alone was not perceived as a long day by all SDPs and LDPs tested. For all SDPs, W LEDs inhibited flowering most effectively. B+R NI was as effective as W NI at creating a long day for all SDPs except chrysanthemum. B+FR NI inhibited flowering of marigold and dahlia ‘Leanne’, but not chrysanthemum or dahlia ‘Gallery Pablo’. For marigold, B+FR NI was less effective than other NI lighting treatments with R light. B+R+FR and R+FR NI similarly delayed flowering of all SDPs except dahlia ‘Gallery Pablo’. NI lighting treatments containing R light similarly promoted flowering of rudbeckia. We conclude that in at least the crops studied, low-intensity B light during the night does not influence flowering. In addition, W LEDs that emit little FR light are effective at creating long days for SDPs but only some LDPs.

Rhizometer: An Apparatus to Observe and Measure Root Growth and Its Effect on Container Substrate Physical Properties Over Time

Container production of plants use substrates that are formulated to have adequate physical properties to sustain optimal plant growth; however, these properties can change over time as a result of substrate settling and root growth of the growing plant in the container. An apparatus (rhizometer) was developed that measures the changes caused by plant roots on physical properties of substrates during crop production in containers. The design of the rhizometer included a clear core, which allowed for observing and measuring a range of root system characteristics in situ, including total root length visible along the rhizometer. Physical properties of planted and fallow rhizometers were measured, and the effect of four species on substrate physical properties was determined. There was a general decrease in substrate total porosity and air space (AS) over time with both fallow and planted rhizometers as a result of both settling of the substrate and root growth into the substrate. Container capacity did not change over time with or without roots. Plants with large root systems such as Begonia ×hybrida acut. decreased AS over time, whereas plants of Rudbeckia hirta L. with a smaller root system did not have the same effect. Measured total root length was highly correlated to the total dry root mass of Tagetes erecta L. and Zinnia marylandica D.M. Spooner, Stimart &amp; T. Boyle plants. This may allow tracing and measuring root lengths to be another (alternative) method to measure root systems. Planted rhizometers also allowed easy access for viewing the root system non-destructively, providing the ability to observe and measure root growth.