Dead Leaves Research Articles

Evaluation of the persistence of Epichloë endophyte and its possible effect on fungal assemblages in dead leaf sheaths

The systemic fungal endophytes of the genus Epichloë inhabit the aerial part of host grasses. Recent studies have reported that Epichloë affects the non-systemic endophytic assemblages in live leaves, but few studies that have demonstrated the occurrence of Epichloë and its effect on fungal assemblages in dead leaves. We proposed a hypothesis that Epichloë decreases from live to dead leaves but affects the non-systemic endophytic assemblages also in dead leaves. To test this hypothesis, we sampled leaf sheaths from four leaf types (live, senescent, attached dead and fallen dead) of two native grass species Elymus racemifer and Elymus tsukushiensis var. transiens in Japan and assessed for fungi by DNA metabarcoding. The occurrence of Epichloë OTU was significantly greater in E. tsukushiensis var. transiens than in E. racemifer and varied significantly between the four-leaf types, with decreased and no detections in attached dead and fallen dead leaves, respectively. The composition of non-systemic endophytic assemblages was also significantly affected by the presence/absence of Epichloë OTU, leaf type, host grass species and their interactions. These results supported our hypothesis and suggested that Epichloë can indirectly lead to the changes in belowground processes such as litter decomposition by affecting saprotrophic fungi in dead leaves.

First record of orange oak leaf - Kallima inachus (Boisd) in Uttar Pradesh, India

A first record of butterfly species Kallima inachus was reported in Uttar Pradesh. A four day preliminary visit to Suhelwa Wildlife Sanctuary from the 6th of March 2022 to the 9th of March 2022 was undertaken and photographs and coordinates of butterfly were taken. The present record confirms the presence of K. inachus in Suhelwa Wildlife Sanctuary and is the first record of this species from the state of Uttar Pradesh.

Influence of erosion control afforestation on some soil parameters in two watersheds in Southwest Bulgaria

Soil is limited resource with vital role in maintenance of variety ecosystems. One of the greatest treat for soils is soil erosion. This natural hazard is widely spread in the terrestrial world, and the territory of Bulgaria is also affected.  Important role for soil protection has a forest vegetation and afforestation is widely used for erosion control activity. The main benefits of afforestation are reduction of water runoff, erosion and sedimentation year-round, which is important for the areas located around the reservoirs and their basins. They also decrease the migration of vital substances for soils and sedimentation yield.  The main goal of the study is to establish the influence of erosion control afforestation to the main soil characteristics in the territory of two watershed situated in Southwest Bulgaria. Soil samples and dead leaf cover were analyzed as well as some characteristics of afforestation and topographic charac-teristics. It was established high water resistance of the soil aggregates under the planted forests and low resistance in the controls. The amounts of content of org. carbon and total nitrogen varying with slope and exposure. The differences between parameters of soils under afforestation and in control samples is established which shows an important influence of forest to the soil characteristics.

Utilizing rubber plant leaf petioles derived activated carbon for high-performance supercapacitor electrodes

This research introduces a novel and sustainable method that exploits the untapped potential of waste biomass, specifically converting dead leaf petioles from Ficus elastica, an industrial crop commonly known as rubber plants, into high-performance activated carbon (AC) for supercapacitor electrodes through a straightforward pyrolysis process. The prepared AC is used as an electrode substance to construct symmetrical supercapacitors. It underwent detailed morphological and structural analyses through various analytical instruments to assess the AC's performance and quality. Electrochemical assessments using a two-electrode configuration with 1 M KOH as the electrolyte revealed that the AC electrodes display exemplary characteristics of electric double-layer capacitance. This conclusion was drawn from observing cyclic voltammetry curves that were rectangular and symmetrical across scan rates ranging from 10 to 100 mV/s. Remarkably, at a scan rate of 10 mV/s, these AC electrodes achieved a specific capacitance of 128 F/g. The superior performance of the AC, when compared to other biomass-derived electrode materials, can be attributed to its extensive surface area and significant porosity. Moreover, electrodes crafted from AC derived from rubber plants showed remarkable durability over 10000 charge-discharge cycles, maintaining 89 % of their original capacitance and achieving a Coulombic efficiency of up to 87 %. During prolonged discharge periods, these electrodes exhibited a high specific capacitance, which contributed to achieving a power density of 200 W/kg and an energy density of 11.4 Wh/kg. This study highlights the viability of rubber plant waste in advanced energy storage systems and significantly contributes to sustainable material science. By offering an eco-friendly approach for supercapacitor electrode fabrication, this research aligns with global efforts towards sustainable energy storage technologies, demonstrating the practicality of environmentally benign materials in high-performance applications.

Ecology and methodology of comparing traits and decomposition rates of green leaves versus senesced litter across plant species and types

Abstract Variation in leaf traits is critical for carbon gains and losses during leaf life and drives litter carbon and nutrient losses via decomposition. Accurately quantifying litter decomposition parameters is essential for assessing ecosystem carbon and nutrient dynamics. Leaf litterbags have commonly been employed to measure effects of environmental drivers, decomposers, and plant traits on decomposition rates. There has been much debate regarding the suitability of substituting senesced dead leaves with fresh (green) leaves in litterbags, which has been common practice for mimicking green leaf fall or for practical reasons. Therefore, we tested the null hypothesis that replacement of dead leaves with fresh leaves in litterbag experiments is justified, based on similarities in structural and chemical traits between fresh and dead leaves across plant species and growth forms. We conducted a paired litterbag decomposition experiment with both fresh and dead leaves of 26 common species in subtropical China, in each of five contrasting ecosystems. While fresh leaves generally decomposed faster than dead leaves, this deviation varied among species and growth forms, based on their traits. Overall, there was significant but rather weak correlation between dead leaf decomposition rate k and fresh leaf k, across species and ecosystem types; the deviation between fresh and dead leaf k was larger for fast‐decomposing, mostly herbaceous species. The different decomposition patterns for fresh versus dead leaves were underpinned by key underlying traits integrated in leaf resource economics spectra (LES) for fresh and dead leaves. The dead leaf LES exhibited a greater predictive capability for dead leaf k while the fresh leaf LES had higher explanatory value for the fresh leaf k values. Our findings partly reject the null hypothesis and ask for caution in inferring leaf litter decomposition rates based on green leaf litterbags or traits data. We suggest follow‐up research on substituting senesced roots and stems with fresh ones in decomposition experiments. Synthesis. Human activities and extreme weather events are leading to increasing pulse inputs of fresh plant parts and our study contributes to knowledge on how they contribute to overall decomposition rates besides senesced litter inputs.

Summer habitat for the female Tricolored Bat (Perimyotis subflavus) in Tennessee, United States

Abstract The Tricolored Bat is an imperiled species due to white-nose syndrome. There is limited information available on roosting and foraging area use of the species to support planning and management efforts to benefit recovery in the Southeastern United States. Female tricolored bats exit hibernation and allocate energy toward disease recovery, migration, and reproduction. Providing and managing for summer habitat is 1 strategy to promote recovery. We sought to: (1) determine local- and landscape-scale factors that influence female Tricolored Bat roost selection; (2) quantify land cover use in core and overall foraging areas; and (3) define foraging area size and distances traveled by female tricolored bats in Tennessee. Bats in this study roosted in trees of variable sizes, in multiple tree species with large canopy volumes, and almost always roosted in trees with dead leaf foliage suspended in the canopy. Forest plots used by bats had trees averaging 30 cm diameter at breast height, basal areas averaging 27 m2/ha, contained multiple tree species, and comprised around a 50:50 ratio of canopy and subcanopy trees. Bats did not roost in coniferous forest areas and were only located in deciduous and mixed forest areas. Bats foraged near and directly over water, in open areas, and along forest edges. This study increases our knowledge on habitat requirements of the species in a temperate region dominated by unfragmented forests and many large water bodies and serves a baseline for management and efforts to benefit survival, reproduction, and population recovery.

Catalytic Ozonation of Reactive Black 5 in Aqueous Solution Using Iron-Loaded Dead Leaf Ash for Wastewater Remediation.

In the current study, iron-loaded dead leaf ash (Fe-DLA) was used as a novel catalyst in the heterogeneous catalytic ozonation process (HCOP) for textile wastewater containing Reactive Black 5 (RB-5). The research demonstrates a significant boost in removal efficiency, reaching 98.76% with 1.0 g/min O3 and 0.5 g/L catalyst dose, by investigating key variables such as pH, ozone and catalyst doses, initial concentration, and the presence of scavengers in 1 L wastewater. The addition of tert-butyl alcohol (TBA) reduced RB-5 elimination, indicating the involvement of OH radicals. Catalyst reusability decreased slightly (2.05% in the second run; 4.35% in the third), which was attributed to iron leaching. A comparison of single ozonation (Fe-DLA) adsorption and catalytic ozonation processes (Fe-DLA/O3) revealed that the combined process improved dye degradation by 25%, with removal rates ranking as Fe-DLA adsorption O3 Fe-DLA/O3, with an impressive 76.44% COD removal. These results strongly support RB-5 removal using Fe-DLA and HCOP at a basic pH, highlighting the catalyst's utility in practical wastewater treatment.

Ecological significance of marcescence in Himalayan plants: Why is standing dead phytomass more important in demanding, resource‐limited environments?

Abstract Understanding mechanisms allowing plants to thrive in challenging conditions is critical for predicting their responses to global environmental change. An often overlooked ecological adaptation is marcescence, where leaves and stems are retained beyond their typical shedding time, with implications for nutrient recycling and carbon sequestration. Marcescence can be expected in plants with conservative resource‐use strategies, especially in environments with limited resources and marked seasonality, such as deserts and alpine regions. However, the extent to which marcescence occurs in different taxa across different habitats and its relationship to seasonality and plant functioning as reflected in ecophysiological traits remains understudied. We studied 600 individuals across 40 Himalayan herb species found in desert, steppe, alpine and subnival habitats, spanning 3000–5400 m elevation. Marcescence was observed in 37 of the 40 species evaluated, with 57% of the sampled individuals displaying dead phytomass, indicating the widespread nature of this phenomenon in Himalayan ecosystems. Environment and plant traits emerged as significant factors influencing the amount of dead‐standing biomass. These findings remained robust after accounting for intraspecific variation and phylogenetic inertia. Desert and steppe species exhibited greater marcescent biomass, characterized by 10‐fold more dead stem biomass than alpine and subnival plants. In contrast, the proportion of dead phytomass increased with elevation due to increased dead leaf fraction. Taller desert species with heavily lignified stems and limited nitrogen and phosphorus content had high levels of stem marcescence, which not only may aid litter photodegradation and nutrient recycling but also deter herbivory and promote seed dispersal (tumbleweed). Conversely, slow‐growing alpine and subnival plants with higher water‐use efficiency, foliar C:N ratios and parenchymatic storage tissue rich in mobile carbohydrates had a high proportion of marcescent leaves, which may aid survival in these resource‐limited environments by providing delayed nutrients through moisture‐conserving mulch that also provides insulation and protection from frost. This study provides new insights into the complex interplay of habitat, seasonality and plant traits in dead phytomass retention in Himalayan plants. Marcescence is prevalent in resource‐conservative species in highly seasonal, resource‐limited habitats and may significantly shape the functioning and biodiversity of Himalayan ecosystems. Read the free Plain Language Summary for this article on the Journal blog.

Nature's disguise: Empirical demonstration of dead-leaf masquerade in Kallima butterflies.

Animals deploy diverse color-based defenses against predators, including crypsis, mimicry, aposematism, and masquerade. While crypsis, mimicry, aposematism have been extensively studied, the strategy of masquerade-where organisms imitate inedible or inanimate objects such as leaves, twigs, stones, and bird droppings-remains comparatively underexplored, particularly in adult butterflies. The Indian oakleaf butterfly ( Kallima inachus) exemplifies this phenomenon, with its wings resembling dead leaves, providing a classic example of natural selection. Although it has long been postulated that these butterflies evade predation by being misidentified as dead leaves, direct experimental evidence is lacking. In the current study, using domestic chicks as predators, we manipulated their prior experience with dead leaves (model objects) while maintaining constant exposure to butterflies to test whether dead-leaf masquerade provides a protective advantage by preventing recognition. Results showed a marked delay in the initiation of attacks by chicks familiar with dead leaves compared to those with no prior exposure or those exposed to visually altered leaves. Chicks with prior dead-leaf experience required a similar amount of time to attack the butterflies as they did to attack dead leaves. These findings provide the first empirical demonstration of dead-leaf masquerade in Kallima butterflies, shedding light on its evolutionary significance. Our study highlights the effectiveness of masquerade in inducing the misclassification of butterflies as inanimate objects, showcasing the precise mimicry achieved by these organisms when viewed in isolation from the model objects. This study advances our understanding of the evolution of masquerade and its role as a potent antipredator strategy in nature.

The life history of Kallima inachus inachus (Lepidoptera: Nymphalidae) on Strobilanthes clarkei for the first time from Vijaynagar, Arunachal Pradesh, India

The life cycle of Kallima inachus inachus (Doyère, [1840]) has been studied in detail from Vijaynagar, Changlang District, Arunachal Pradesh, India. The larvae of this species feed on Strobilanthes clarkei belonging to the family Acanthaceae, which is being reported here as a new larval host plant of K. i. inachus from India. The eggs were laid singly beneath the surface of the host plant and occasionally near the larval host plant. The entire life history from the incubation period to the enclosing of the adult was completed in 55 to 57 days. During the present study, adult longevity was recorded as 9–12 days. The entire time span and the measurement of various life cycle stages have been discussed.

Identification, pathogenicity, and fungicide sensitivity of Eutiarosporella dactylidis associated with leaf blight on maize in China

Maize (Zea mays L.) is an economically vital grain crop that is cultivated worldwide. In 2011, a maize foliar disease was detected in Lingtai and Lintao counties in Gansu Province, China. The characteristic signs and symptoms of this disease include irregular chlorotic lesions on the tips and edges of infected leaves and black punctate fruiting bodies in dead leaf tissues. Given favourable environmental conditions, this disease spread to areas surrounding Gansu. In this study, infected leaves were collected from Gansu and Ningxia Hui Autonomous Region between 2018 and 2020 to identify the disease-causing pathogen. Based on morphological features, pathogenicity tests, and multi-locus phylogenetic analysis involving internal transcribed spacer (ITS), 18S small subunit rDNA (SSU), 28S large subunit rDNA (LSU), translation elongation factor 1-alpha (TEF), and β-tubulin (TUB) sequences, Eutiarosporella dactylidis was identified as the causative pathogen of this newly discovered leaf blight. Furthermore, an in vitro bioassay was conducted on representative strains using six fungicides, and both fludioxonil and carbendazim were found to significantly inhibit the mycelial growth of E. dactylidis. The results of this study provide a reference for the detection and management of Eutiarosporella leaf blight.

Evolutionary genomics of camouflage innovation in the orchid mantis

The orchid mantises achieve camouflage with morphological modifications in body color and pattern, providing an interesting model for understanding phenotypic innovation. However, a reference genome is lacking for the order Mantodea. To unveil the mechanisms of plant-mimicking body coloration and patterns, we performed de novo assembly of two chromosome-level genomes of the orchid mantis and its close relative, the dead leaf mantis. Comparative genomic analysis revealed that the Scarlet gene plays an important role in the synthesis of xanthommatin, an important pigment for mantis camouflage coloration. Combining developmental transcriptomic analysis and genetic engineering experiments, we found that the cuticle was an essential component of the ‘petal-like’ enlargement, and specific expression in the ventral femur was controlled by Wnt signaling. The prolonged expression of Ultrabithorax (Ubx) accompanied by femoral expansion suggested that Ubx determines leg remodeling in the early developmental stage. We also found evidence of evolution of the Trypsin gene family for insectivory adaptation and ecdysone-dependent sexual dimorphism in body size. Overall, our study presents new genome catalogs and reveals the genetic and evolutionary mechanisms underlying the unique camouflage of the praying mantis, providing evolutionary developmental insights into phenotypic innovation and adaptation.

Residential greenspace and anxiety symptoms among Australian women living in major cities: A longitudinal analysis

Despite an increasing number of studies demonstrating the potential mental health benefits of greenspace, few longitudinal studies have been reported. We aimed to assess associations between two metrics of residential greenspace exposure and anxiety symptoms in a cohort of Australian women living in major cities.Our study comprised 3,938 women, born between 1973 and 78. Anxiety symptoms in the previous month were assessed at follow-up every three years during 2003–2018, using the anxiety subscale of the Goldberg Anxiety and Depression Scale. The three-month seasonal average normalized difference vegetation index (NDVI) was estimated from 30 m Landsat satellite images in a 500 m buffer (NDVI500m) around participants’ address at each survey (higher NDVI indicates more green vegetation). The annual fractional cover of non-photosynthesising vegetation was estimated (fNPV500m, with higher values indicating greater levels of dead leaf litter or dry grass).A generalised estimating equation assessed associations between greenspace measures and anxiety symptoms (as odds ratios [ORs]), adjusting for repeated outcomes and individual-level covariates. Additional analyses focused on women experiencing substantial changes in between-survey exposure due to moving, and adjusting for nitrogen dioxide (NO2) and fine particulate matter (PM2.5) exposure, among others.A standard deviation (SD) (0.12 units) increase in NDVI500m was significantly associated with lower odds of anxiety symptoms (OR: 0.96, 95% CI: 0.93–0.99) in the adjusted model. An SD (5.2%) increase in annual fNPV500m was consistent with the direction expected for that exposure, but not significant in the adjusted model (OR: 1.03, 95% CI: 0.99–1.07). NDVI500m was modestly attenuated when air pollutants were adjusted for, while fNPV500m only became significant when PM2.5 was adjusted for. Between-survey contrasts had no clear effect for NDVI500m. Moving to a higher fNPV500m area, compared with a similar fNPV500m area, was consistently associated with anxiety symptoms (OR: 1.15, 95% CI: 1.02–1.31). NDVI500m was generally associated with lower odds of anxiety symptoms, while fNPV500m was generally associated with higher odds of anxiety, depending on the covariates considered.

Decoupling wing-shape effects of wing-swept angle and aspect ratio on a forward-flying butterfly.

The effect of wing shape on a forward-flying butterfly via decoupled factors of the wing-swept angle and the aspect ratio (AR) was investigated numerically. The wing-shape effect is a major concern in the design of a microaerial vehicle (MAV). In nature, the wing of a butterfly consists of partially overlapping forewing and hindwing; when the forewing sweeps forward or backward relative to the hindwing, the wing-swept angle and the AR of the entire wing simultaneously change. The effects of the wing-swept angle and AR on aerodynamics are coupled. To decouple their effects, we established wing-shape models with varied combinations of the wing-swept angle and AR based on the experimental measurement of two butterfly species (Papilio polytes and Kallima inachus) and developed a numerical simulation for analysis. In each model, the forewing and hindwing overlapped partially, constructing a single wing. Across the models, the wing-swept angle and AR of these single wings varied sequentially. The results show that, through our models, the effects of the wing-swept angle and AR were decoupled; both have distinct flow mechanisms and aerodynamic force trends and are consistent in the two butterfly species. For a fixed AR, a backward-swept wing increases lift and drag because of the enhanced attachment of the leading-edge vortex with increased strength of the wingtip vortex and the spanwise flow. For a fixed wing-swept angle, a small AR wing increases lift and decreases drag because of the large region of low pressure downstream and the wake-capture effect. Coupling these effects, the largest lift-to-drag ratio occurs for a forward-swept wing with the smallest AR. These results indicate that, in a flapping forward flight, sweeping a forewing forward relative to a hindwing is suitable for cruising. The flow mechanisms and decoupled and coupled effects of the wing-swept angle and the AR presented in this paper provide insight into the flight of a butterfly and the design of a MAV.

Insect Pest Incidence with the System of Rice Intensification: Results of a Multi-Location Study and a Meta-Analysis

The System of Rice Intensification (SRI) developed in Madagascar has spread to many parts of the world, including India. This study assessing insect pest prevalence on rice grown with SRI vs. conventional methods at multiple locations in India was prompted by reports that SRI-managed rice plants are healthier and more resistant to pest and disease damage. Field experiments were conducted under the All-India Coordinated Rice Improvement Project over a 5-year period. The split-plot design assessed both cultivation methods and different cultivars, hybrids and improved varieties. Across the eight locations, SRI methods of cultivation showed a lower incidence of stem borer, planthoppers, and gall midge compared to conventional methods. Whorl maggots and thrips, on the other hand, were observed to be higher. Grain yield was significantly higher with SRI management across all locations. Higher ash, cellulose, hemicellulose, as well as silica content in rice plants under SRI management could explain at least in part the SRI plants’ resistance to pest damage. Analysis of guild composition revealed that in SRI plots, there were more natural enemies (insect predators and parasitoids) present and fewer crop pests (phytophages). A meta-analysis that considered other published research on this subject revealed a lower incidence of dead hearts, white ear-heads, and leaf folders, along with higher grain yield, in SRI plots.

Rastrojo: Re(in)surgent forests

<i>Rastrojo</i>: Re(in)surgent forests

Quantifying Forest Litter Fuel Moisture Content with Terrestrial Laser Scanning

Electromagnetic radiation at 1550 nm is highly absorbed by water and offers a novel way to collect fuel moisture data, along with 3D structures of wildland fuels/vegetation, using lidar. Two terrestrial laser scanning (TLS) units (FARO s350 (phase shift, PS) and RIEGL vz-2000 (time of flight, TOF)) were assessed in a series of laboratory experiments to determine if lidar can be used to estimate the moisture content of dead forest litter. Samples consisted of two control materials, the angle and position of which could be manipulated (pine boards and cheesecloth), and four single-species forest litter types (Douglas-fir needles, ponderosa pine needles, longleaf pine needles, and southern red oak leaves). Sixteen sample trays of each material were soaked overnight, then allowed to air dry with scanning taking place at 1 h, 2 h, 4 h, 8 h, 12 h, and then in 12 h increments until the samples reached equilibrium moisture content with the ambient relative humidity. The samples were then oven-dried for a final scanning and weighing. The spectral reflectance values of each material were also recorded over the same drying intervals using a field spectrometer. There was a strong correlation between the intensity and standard deviation of intensity per sample tray and the moisture content of the dead leaf litter. A multiple linear regression model with a break at 100% gravimetric moisture content produced the best model with R2 values as high as 0.97. This strong relationship was observed with both the TOF and PS lidar units. At fuel moisture contents greater than 100% gravimetric water content, the correlation between the pulse intensity values recorded by both scanners and the fuel moisture content was the strongest. The relationship deteriorated with distance, with the TOF scanner maintaining a stronger relationship at distance than the PS scanner. Our results demonstrate that lidar can be used to detect and quantify fuel moisture across a range of forest litter types. Based on our findings, lidar may be used to quantify fuel moisture levels in near real-time and could be used to create spatial maps of wildland fuel moisture content.

Effects of foliage-applied exogenous γ-aminobutyric acid on seedling growth of two rice varieties under salt stress.

Exogenous γ-aminobutyric acid (GABA) has been used and regarded as a potential enhancer for plant resistance against various biotic or abiotic attackers in the crop production, especially as a promising alleviator against salt stress. In order to determine whether GABA is truly effective in promoting rice resistance under a certain level of salt stress or not and to evaluate its effect on the growth and some physiological responses of two Japonica rice varieties under salt stress. 3-leaf rice seedlings germinated from seeds were cultivated in a separate hydroponic cup with a nutrient solution that was salinized with 0, 25, 50, or 75 mmol K+ of NaCl. A 4 mmol L-1 GABA solution or water were sprayed onto leaves once a day for 8 days prior to an assessment of the seedling growth, the growth indices, root activities and three antioxidant enzyme activities in leaves were measured. Data analyses indicated that as the salt concentration increased, the plant height and the leaf area of both rice varieties decreased, while the dead leaf rate, weight ratio of the dry- and fresh-roots, superoxide dismutase (SOD) and peroxidase (POD) activities increased. Under the same saline conditions, the root activities and the leaf ascorbate peroxidase (APX) activity were enhanced at a low NaCl concentration but reduced when the salt concentration was high. A foliar application of GABA daily on both rice varieties for over a week under 3 different salinized treatments as compared with the corresponding treatments sprayed with water resulted in an enhanced effect on plant height increment by 1.7-32.4%, a reduction of dead leaf rate by 1.6-36.4%, a decline of root dry weight by 9.3-30.9% respectively, and an increment in root activities by 8.1-114.5%, and POD, SOD and APX enzyme activities increased by 5.0-33.3%, 4.1-18.5%, and 7.2-64.4% respectively. However, two rice varieties showed a significant difference in response to various salinized levels. Overall results of this study demonstrate that the application of exogenous GABA on the leaves of rice seedlings under salt stress has improved rice salt tolerance, which should provide a sufficient information for ultimately making it possible to grow rice in salinized soil.

In vitro callus and shoot initiation of Black cohosh (Actaea racemosa. L) pre-incubated in darkness treatments

A medicinal plant that is commonly overharvested in its native habitat, Black cohosh (Actaea racemosa L.) rhizomes are used to mitigate symptoms of menopause and are a common alternative to hormone replacement therapy. Developing an accurate protocol for initiation of Black cohosh in tissue culture is becoming a necessity. Wild harvesting practices are the main source of Black cohosh rhizomes processed by pharmaceutical companies and are causing a significant decrease of these wild plants, leading to an At-Risk status. Growing these plants in a plant tissue culture laboratory is more sustainable than current practices, and having an accurate protocol for initiation of these plants is crucial to this. Our lab has previously developed a protocol for initiation of Black cohosh and this research was meant to optimize this protocol. Leaf explants of Black cohosh were cultured in vitro to determine the optimal duration of time for initiation of callus and/or shoot under darkness, and appropriate plant growth regulators (PGR) for shoot growth. Leaf explants incubated under darkness for increasing amount of time (0 to 6 weeks of darkness) were analyzed at two stages of tissue development. Stage 1 involved initiation of leaf explant material under darkness (treatment) and measured the callus development in leaf explants; Stage 2 was induction of adventitious shoot growth and cell division and compared the effect of two PGRs, KT and BA, on shoot growth for each darkness treatment. Leaf explants were given a score using a culture chart that assigns a numerical score to leaf explants based on their physiological characteristics. These numerical scores took into account color of leaf explant, callus development, shoot growth, and presence of dead leaf tissue. Stage 2 measured the number of shoots produced per explant within culture containers between PGRs and the number of weeks in darkness. Overall trends indicated that mortality of leaf explants decreased as the duration of incubation under darkness increased with mortality of explants decreasing from 63.9% (T0 darkness treatment) to 2.8% (T6 darkness treatment). Culture scores of explants (including dead explants) was highest for T6 weeks of darkness (culture score 2.96 on average), and for culture scores without dead explants (culture score of 3.05). During the adventitious shoot growth stage, however, T5 weeks of darkness performed significantly higher (KT: 28 shoots/ BA: 17.3 shoots) than T6 weeks of darkness (KT: 12.9 shoots/ BA: 9.4) in Replication 2 for both plant growth regulators KT PGR performed better, on average, than BA PGR

Irrigation effects on elephant grass morphology, and its genotype‐dependent responses

AbstractThis study hypothesised that different elephant grass genotypes respond differently in terms of their morphological development to irrigation. The objective of this study was to evaluate how water availability could affect the morphological development of different genotypes of elephant grass. The treatments consisted of four genotypes of elephant grass [Cenchrus purpureus (Schumach.) Morrone], managed under irrigation or not, during a two‐year field trial. The experiment was arranged in a randomised block design in a split‐plot, with four replicates per treatment (n = 4). Between the genotypes, two of them were classified as tall‐sized (IRI 381 and Elephant B), and two as dwarfs (Taiwan A‐146 2.37 and Mott). A three‐way interaction between season, irrigation, and genotype affected the variables plant height, stem diameter, number of dead tillers, light interception (LI), and leaf area index (LAI) (p &lt; .05). The morphological development of all genotypes was negatively impacted by the dry season. All genotypes grew taller during the rainy season (p &lt; .05) and had a greater light interception (62%–80%) compared to the dry period (28%–59%). The genotype Mott, showed comparable LI and LAI to the tall‐sized genotypes, whilst Taiwan A‐146 2.37 was characterized by the lowest values, despite being the genotype with the greatest tiller density (60 tillers m−2) (p &lt; .05). The use of irrigation mitigated the negative effects of the dry season on the plants, however, the type and size (tall vs. dwarf) of the elephant grass genotypes defined the extent of the responses to the use of the irrigation during the dry period.