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The proliferation of vigorous lianas usually forms liana canopies over the crowns of host trees and liana mats on the ground of open areas or large forest gaps. While research on liana canopies has increased significantly in recent decades, our understanding of liana mats remains limited. Merremia boisiana (Convolvulaceae), a fast-growing liana, forms mature liana mats that can persist for decades, characterized by numerous upright searcher shoots that extend from the liana mats in search of supports. However, the reasons behind the proliferation of these searchers, as well as their growth and branching patterns in mature liana mats that lack support, are not well understood. We hypothesize that searchers are an inevitable phase in the growth rhythm of M. boisiana within these mature liana mats. We tested our hypothesis by tracking the lifespan and status of M. boisiana searchers during the early, middle, and late periods of the year. Our findings reveal the following: (1) M. boisiana searchers exhibit apical dominance and have a short lifespan; over 95% of searchers lost their terminal buds within two months during the early period, while it took only one month during the middle and late periods. (2) The original lateral buds of the searchers also have a limited lifespan, yet the nodes can sprout new lateral buds after the loss of their originals. (3) With the withering of terminal buds, the total number of lateral shoots decreased, while the quantity of long lateral shoots (≥ 50 cm) and their elongation rates increased. (4) Each surviving segment of a searcher typically develops one or two long lateral shoots, none of which grow into searchers. We conclude that the shoots of M. boisiana in mature liana mats periodically alternate between searchers and stolons, collectively forming a zigzag branching system. The high rate of lateral bud resprouting may facilitate the rapid recovery of mature liana mats early in the year, while the reduced lifespan of searchers and limited number of long lateral shoots represent effective strategies for M. boisiana , balancing the investment and risk associated with foraging in mature liana mats. [ABSTRACT FROM AUTHOR]

The proliferation of vigorous lianas usually forms liana canopies over the crowns of host trees and liana mats on the ground of open areas or large forest gaps. While research on liana canopies has increased significantly in recent decades, our understanding of liana mats remains limited. Merremia boisiana (Convolvulaceae), a fast-growing liana, forms mature liana mats that can persist for decades, characterized by numerous upright searcher shoots that extend from the liana mats in search of supports. However, the reasons behind the proliferation of these searchers, as well as their growth and branching patterns in mature liana mats that lack support, are not well understood. We hypothesize that searchers are an inevitable phase in the growth rhythm of M. boisiana within these mature liana mats. We tested our hypothesis by tracking the lifespan and status of M. boisiana searchers during the early, middle, and late periods of the year. Our findings reveal the following: (1) M. boisiana searchers exhibit apical dominance and have a short lifespan; over 95% of searchers lost their terminal buds within two months during the early period, while it took only one month during the middle and late periods. (2) The original lateral buds of the searchers also have a limited lifespan, yet the nodes can sprout new lateral buds after the loss of their originals. (3) With the withering of terminal buds, the total number of lateral shoots decreased, while the quantity of long lateral shoots (= 50 cm) and their elongation rates increased. (4) Each surviving segment of a searcher typically develops one or two long lateral shoots, none of which grow into searchers. We conclude that the shoots of M. boisiana in mature liana mats periodically alternate between searchers and stolons, collectively forming a zigzag branching system. The high rate of lateral bud resprouting may facilitate the rapid recovery of mature liana mats early in the year, while the reduced lifespan of searchers and limited number of long lateral shoots represent effective strategies for M. boisiana, balancing the investment and risk associated with foraging in mature liana mats. [ABSTRACT FROM AUTHOR]

The white grubs infests diverse crops of food and horticultural importance such as groundnut, sugarcane, kharif pulses, vegetables areca nut, ginger, potato, etc. and it inflict losses as high as 100 per cent, depending upon the severity of infestation have been uncommon. In present study, attemts have been made to explore the potentiality of entomopathogens for the management of the white grub Holotrichia consanguinea a serious pest in groundnut crop in Rajasthan during kharif seasons, 2018 and 2019. Results revealed that furrow application of Beauveria bassiana, Metarhizium anisopliae powder formulation @ 5 kg (1×1012 CFU/gm) and H. indica galleria @ 5000 galleria per hectare at the time of sowing were significantly superior in reducing the per cent plant mortality (28.00%, 29.33%, 31.77%, respectively) and increase yield over untreated control (12.82, 11.53, 10.78 q/ha respectively). [ABSTRACT FROM AUTHOR]

Given the pressing challenges posed by climate change, it is crucial to develop a deeper understanding of the impacts of escalating drought and heat stress on terrestrial ecosystems and the vital services they offer. Soil and plant water potential play a pivotal role in governing the dynamics of water within ecosystems and exert direct control over plant function and mortality risk during periods of ecological stress. However, existing observations of water potential suffer from significant limitations, including their sporadic and discontinuous nature, inconsistent representation of relevant spatio-temporal scales and numerous methodological challenges. These limitations hinder the comprehensive and synthetic research needed to enhance our conceptual understanding and predictive models of plant function and survival under limited moisture availability. In this article, we present PSInet (PSI—for the Greek letter Ψ used to denote water potential), a novel collaborative network of researchers and data, designed to bridge the current critical information gap in water potential data. The primary objectives of PSInet are as follows. (i) Establishing the first openly accessible global database for time series of plant and soil water potential measurements, while providing important linkages with other relevant observation networks. (ii) Fostering an inclusive and diverse collaborative environment for all scientists studying water potential in various stages of their careers. (iii) Standardizing methodologies, processing and interpretation of water potential data through the engagement of a global community of scientists, facilitated by the dissemination of standardized protocols, best practices and early career training opportunities. (iv) Facilitating the use of the PSInet database for synthesizing knowledge and addressing prominent gaps in our understanding of plants' physiological responses to various environmental stressors. The PSInet initiative is integral to meeting the fundamental research challenge of discerning which plant species will thrive and which will be vulnerable in a world undergoing rapid warming and increasing aridification. [ABSTRACT FROM AUTHOR]

Sesamum indicum L. (sesame) is a traditional oilseed crop grown extensively in tropical and subtropical areas. In recent years, it has received more attention due to the health-promoting properties of its seed oil. Although production increased globally, its productivity is very low in different regions due to the harmful effects of biotic and abiotic stresses. Therefore, studying the environmental stress response mechanisms for improving productivity and yield is crucial in sesame research. Drought is a major abiotic stress that adversely affects sesame productivity worldwide. Sesame is typically a drought-tolerant crop; however, intense and prolonged drought limits its growth and impairs flower production, ultimately affecting the yield and sometimes resulting in plant mortality. Different varieties of sesame exhibit contrasting responses to drought stress, indicating the existence of different molecular mechanisms. The paper discusses the advancement in screening methodologies for drought tolerance, inheritance, biochemical and molecular aspects, transgenic approaches, and quantitative trait loci (QTL) associated with drought stress tolerance in sesame with the aid of citation network analysis (CNA). [ABSTRACT FROM AUTHOR]

This study focused on evaluating the growth and productivity of Coffea arabica var. Esperanza L4A5 in different agroforestry systems in the Caribbean region of Costa Rica, a non-traditional area for coffee cultivation due to its low altitude and challenging climatic conditions. Three tree coverages were investigated, in combination with two types of differentiated fertilization (physical and chemical), comparing the results with full sun coffee plots as a control: (1) Albizia saman, (2) Hymenaea courbaril + Erythrina poeppigiana, and (3) Anacardium excelsum + Erythrina poeppigiana. The results showed that tree associations significantly reduced the mortality of coffee plants and increased both the height and mature cherry production compared to full sun treatments. In particular, the tree coverages associated with chemical and physical fertilization achieved the highest growth and production rates, with A. excelsum + E. poeppigiana and H. courbaril + E. poeppigiana standing out with maximum mature cherry productions of 3.35 t/ha and 3.28 t/ha, respectively. Growth analysis revealed that rapid initial growth, especially under chemical fertilization, is crucial for maximizing productivity, although a rapid slowdown in growth was also observed after reaching the peak. These findings underscore the importance of combining tree coverages with appropriate fertilization strategies to optimize coffee production in agroforestry systems, particularly in low-altitude areas like the Costa Rican Caribbean. This study concludes that agroforestry systems not only improve the resilience of coffee crops to adverse environmental conditions but can also be a viable strategy for increasing productivity in non-conventional regions. This suggests the need for further research to assess the long-term impacts on soil health, biodiversity, and the economic viability of these systems. [ABSTRACT FROM AUTHOR]

Mediterranean ecosystems are predicted to undergo longer and more intense summer droughts. The mechanisms underlying the response of herbaceous communities to such drier environments should be investigated to identify the resilience thresholds of Mediterranean rangelands. A 5‐year experiment was conducted in deep and shallow soil rangelands of southern France. A rainout shelter for 75 days in summer imposed drier and warmer conditions. Total soil water content was measured monthly to model available daily soil water. Aboveground net primary production (ANPP), forage quality, and the proportion of graminoids in ANPP were measured in spring and autumn. Plant senescence and plant cover were assessed in summer and spring, respectively. The experimental years were among the driest ever recorded at the site. Therefore, manipulated summer droughts were drier than long‐term ambient conditions. Interactions between treatment, community type, and experimental year were found for most variables. In shallow soil communities, spring plant cover decreased markedly with time. This legacy effect, driven by summer plant mortality and the loss of perennial graminoids, led to an abrupt loss of resilience when the extreme water stress index exceeded 37 mm 10 day−1, characterized by a reduction of spring plant cover below 50% and a decreased ANPP in rainy years. Conversely, the ANPP of deep soil communities remained unaffected by increased summer drought, although the presence of graminoids increased and forage nutritive value decreased. This study highlights the role of the soil water reserve of Mediterranean plant communities in modulating ecosystem responses to chronically intensified summer drought. Communities on deep soils were resilient, but communities on shallow soils showed a progressive, rapid, and intense degradation associated with a loss of resilience capacity. Notably, indexes of extreme stress were a better indicator of tipping points than indexes of integrated annual stress. Considering the role of soil water availability in other herbaceous ecosystems should improve the ability to predict the resilience of plant communities under climate change. [ABSTRACT FROM AUTHOR]

Terrestrial water fluxes are substantially mediated by vegetation, while the distribution, growth, health, and mortality of plants are strongly influenced by the availability of water. These interactions, playing out across multiple spatial and temporal scales, link the disciplines of plant ecophysiology and ecohydrology. Despite this connection, the disciplines have provided complementary, but largely independent, perspectives on the soil‐plant‐atmosphere continuum since their crystallization as modern scientific disciplines in the late 20th century. This review traces the development of the two disciplines, from their respective origins in engineering and ecology, their largely independent growth and maturation, and the eventual development of common conceptual and quantitative frameworks. This common ground has allowed explicit coupling of the disciplines to better understand plant function. Case studies both illuminate the limitations of the disciplines working in isolation, and reveal the exciting possibilities created by consilience between the disciplines. The histories of the two disciplines suggest opportunities for new advances will arise from sharing methodologies, working across multiple levels of complexity, and leveraging new observational technologies. Practically, these exchanges can be supported by creating shared scientific spaces. This review argues that consilience and collaboration are essential for robust and evidence‐based predictions and policy responses under global change. Summary statement: Ecophysiology and ecohydrology share an interest in plant–water interactions but have largely developed and operated along distinct paths. We review the development of these fields and difficulties that emerged and argue how greater consilience can address pressing challenges under global change. [ABSTRACT FROM AUTHOR]

The substantial use of medicinal plants in traditional poultry farming is a well-established practice. The present study aimed to determine the median lethal dose (LD50) of ethanolic extracts of Jatropha multifida and Hyptis suaveolens in local chickens and to assess the effects of these extracts on feed intake, water intake, and average body weight. The methodology followed OECD Directive 223, which involves administering the highest dose of the extract to the chickens and assessing any mortality. Three homogeneous groups of five chickens each were formed for the limit dose test. The control group received distilled water, while batches 1 and 2 received 700 mg of ethanolic extract of J. multifida and H. suaveolens, respectively. The average body weight of the chickens was 350g ± 20, and the extracts were administered via gavage at a suspension of 2000 mg/kg.bwt of the extract dissolved in water. The results of the phytochemical tests indicated the presence of several chemical compounds known for their therapeutic effects. The productivity of the extract was 2.75 ± 0.19 for J. multifida and 3.3 ± 0.27 for H. suaveolens. After administration of the suspensions, observation for 14 days revealed no mortality. This finding indicated that the LD50 of the utilized ethanolic extracts exceeds the limit dose (2000 mg/kg.bwt). However, feed intake (49 ± 3 > 46±4) and average body weight (436 ± 31 > 388 ± 37) in batch 2 were significantly higher than those in batch 1. Future research should explore the subacute toxicity of J. multifida and H. suaveolens across various chicken breeds. [ABSTRACT FROM AUTHOR]

This study employed two prevalent plastic products - straws and microfiber as microplastics (MPs) to elucidate their largely unexplored effects on soil's properties and the growth of the tomato plant (Solanum lycopersicum L.). For this experiment, a completely randomized design (CRD) was adopted where, straw - polypropylene (PP), microfiber - polyester (PES) + polyamide (PA), and their combinations (PP + PES + PA) were mixed with soil using different concentrations – 0% (control), 0.4%, 1%, and 2% (treatments) and kept for 45 days at room temperature. The findings demonstrated that incorporating 2% mixed MPs in soil significantly decreased bulk density and electrical conductivity 7.29% and 67.3%, respectively, while soil pH increased 17.84% in cultures containing 1% microfiber. Maximum water holding capacity (MWHC), soil organic carbon (SOC), and soil organic matter (SOM) showed varied responses based on MPs type and concentration. Specifically, MWHC increased 16.4% with 2% microfiber but declined 13.3% with 0.4% straw. The highest decreased (30.65%) in SOC and SOM were evident in cultures with 1% microfiber whereas increased 9.68% and 8.33% in cultures with 0.4% straw. In terms of the growth traits of S. lycopersicum, substantial reductions in plant height (56.37%), leaf number (54.37%), and girth diameter (56.43%) were observed in 2% straw containing cultures. Although no plant mortality was noted, the most pronounced reductions in leaf area (62.44%) and total plant biomass (68.16%) occurred in 2% microfiber cultures. Therefore, the ramifications of these findings may contribute to a deeper comprehension of the mechanisms and effects of MPs on soil properties and above-ground plant growth. [ABSTRACT FROM AUTHOR]

Bean flower thrips (Megalurothrips usitatus) is a major French bean (Phaseolus vulgaris L.) pest. Small‐scale farmers manage the pest using mixed plant extracts although their efficacy has not been scientifically validated. We evaluated the efficacy of mixed plant extracts comprising; Capsicum frutescens, Allium sativum, Lantana camara, Tagetes minuta and Azadirachta indica, against M. usitatus under laboratory and screenhouse. We identified and quantified the secondary metabolites associated with insecticidal activity using spectrophotometry and liquid chromatography–mass spectrometry (LC–MS). The plant combinations included PE1 (C. frutescens + A. sativum + L. camara + T. minuta extracts infused for 14 days), PE2 (same as PE1 but infused for 24 h) and PE + N (the five plant extracts infused for 24 h) in distilled water. We used an organic commercial botanical (Pyneem) as a positive control and distilled water as a negative control. Pyneem and PE + N induced the highest mortality at 88% and 77%, respectively, in the laboratory, and 68% and 71%, respectively, in the screenhouse. Phenolics, terpenoids and organosulfur compounds were identified in PE + N and individual plant extracts in varied quantities. These compounds were significantly higher (p < 0.001) in PE + N compared to individual plant extracts. The study showed that PE + N efficiently manages bean flower thrips, and mixing different plant extracts amplifies the secondary metabolites' abundance. The use of mixed plant extracts could be incorporated into integrated pest management strategies for thrips management in legumes. The specific compounds identified in PE + N should be investigated further to understand their modes of action against the pest. [ABSTRACT FROM AUTHOR]

Summary: Drought‐induced xylem embolism is a primary cause of plant mortality. Although c. 70% of cycads are threatened by extinction and extant cycads diversified during a period of increasing aridification, the vulnerability of cycads to embolism spread has been overlooked.We quantified the vulnerability to drought‐induced embolism, pressure–volume curves, in situ water potentials, and a suite of xylem anatomical traits of leaf pinnae and rachises for 20 cycad species. We tested whether anatomical traits were linked to hydraulic safety in cycads.Compared with other major vascular plant clades, cycads exhibited similar embolism resistance to angiosperms and pteridophytes but were more vulnerable to embolism than noncycad gymnosperms. All 20 cycads had both tracheids and vessels, the proportions of which were unrelated to embolism resistance. Only vessel pit membrane fraction was positively correlated to embolism resistance, contrary to angiosperms. Water potential at turgor loss was significantly correlated to embolism resistance among cycads.Our results show that cycads exhibit low resistance to xylem embolism and that xylem anatomical traits – particularly vessels – may influence embolism resistance together with tracheids. This study highlights the importance of understanding the mechanisms of drought resistance in evolutionarily unique and threatened lineages like the cycads. [ABSTRACT FROM AUTHOR]

The pulse beetle is a primary pest of mung bean (Vigna radiata L.), causing heavy losses during storage. Conventional control of pulse beetle with insecticides has led to various challenges. This study sought safer alternatives by exploring the efficacy of hexane extracts derived from seeds of Azadirachta indica and Trachyspermum ammi, Curcuma longa rhizomes, Allium sativum bulbs, Citrullus colocynthis fruits, and Caralluma tuberculata stems against pulse beetle. Each plant extract was tested at six concentrations of 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, and 3.0% w/v, under the constant laboratory conditions of the Gomal University, Dera Ismail Khan, Khyber Pakhtunkhwa, Pakistan. The hexane extracts prepared from A. sativum and C. longa at 3% concentration exhibited significant efficacy, resulting in mortality rates of 99.20% and 94.40% of adult beetles, respectively. Furthermore, mung bean grains treated with the A. sativum extracts at the maximum concentration (3%) demonstrated minimum egg deposition (2.20 per grains-20), prolonged time to adult emergence (25.10 days), minimum progeny emergence (33.40), lowest infestation (5.47%), minimum weight loss (4.39%), and shortest adult life span (8.70 days). The hexane plant extracts prepared from A. sativum and C. longa powders at higher concentrations (2.5% and 3.0%) can benefit the safer management of pulse beetles. [ABSTRACT FROM AUTHOR]

Savannas play a key role in estimating emissions. Climate change has impacted the Cerrado savanna carbon balance. We used the burned area product and long-term field inventories on post-fire vegetation regrowth to estimate the impact of the fire on greenhouse gas emissions and net carbon dioxide (CO2) emissions in the Cerrado savanna between 1985 and 2020. We estimated the immediate emissions from fires, CO2 emissions by plant mortality, and CO2 removal from vegetation regrowth. The burned area was 29,433 km2; savanna fires emitted approximately 2,227,964 Gg of CO2, 85,057 Gg of CO, 3010 Gg of CH4, 5,103 Gg of NOx, and 275 Gg of N2O. We simulated vegetation regrowth according to three fire regime scenarios: extreme (high fire frequency and short fire interval), intermediate (medium fire frequency and medium fire interval), and moderate (low fire frequency and long fire interval). Under the extreme and intermediate scenarios, the vegetation biomass decreased by 2.0 and 0.4% (ton/ha-year), while the biomass increased by 2.1% under a moderate scenario. We converted this biomass into CO2 and showed that the vegetation regrowth removed 63.5% of the total CO2 emitted (2,355,426 Gg), indicating that the Cerrado savanna has been a source of CO2 to the atmosphere. [ABSTRACT FROM AUTHOR]

Key message: The elapsed times to deplete starch concentrations and to reach a null hydraulic safety margin were related to tree seedling mortality under experimental drought. Starch concentration showed an accelerated decline across all species during the early stages of dehydration, while the concentrations of soluble sugars and total nonstructural carbohydrates remained stable. Concomitant carbohydrate depletion and hydraulic failure drive seedling mortality under drought. Context: Current upsurges of drought events are provoking impacts on tree physiology, resulting in forest mortality. Hydraulic dysfunction and nonstructural carbohydrate (NSC) depletion have been posited as the main mechanisms leading to plant mortality under drought. Aims: This study explores the dynamics of the two mortality-inducing processes during drought stress using an experimental approach with 12 evergreen tree species. Methods: Seedlings were subjected to drought until 100% mortality was observed. Midday (ΨMD) and predawn (ΨPD) water potentials, xylem pressure leading to a 50% loss of hydraulic conductivity (Ψ50), along with NSC concentrations in different organs (leaves, stems, and roots) were measured regularly during drought. Results: Total NSC concentrations and soluble sugar pools did not decline during drought. However, starch pools showed strong reductions early during drought stress as ΨPD decreased, and the time leading to starch depletion emerged as a strong mortality predictor. Ψ50 alone did not provide an accurate estimate of mortality, while the elapsed time to reach a null hydraulic safety margin (ΨMD—Ψ50 = 0) was related to seedling mortality. Conclusion: Adopting a dynamic approach by estimating the times to consume both starch reserves and hydraulic safety margins is highly relevant to improve predictions of tree mortality under the current context of increasing global drought. [ABSTRACT FROM AUTHOR]

Herbicide flashback is an undesirable response that results in damage or mortality of non-target plants near chemically treated plants. In severe instances, crop trees can be injured resulting in financial loss or inability to capture management objectives. Land managers need to know the potential limitations of using triclopyr acid (50% solution in water) and what quantity can cause damage to non-target trees (trees not aimed at for control via herbicide). Three naturally regenerated (previously clearcut) bottomland hardwood sites, ranging from 14–20 years of age, received partial overstory deadening using Trycera® herbicide. Residual "leave" trees experienced indirect herbicide uptake resulting in some trees either experiencing mortality or partial mortality with top dieback/epicormic branching. An increased probability of damage occurred as tree diameter decreased and the number of treated stems around the non-target stems increased. American sycamore, green ash, and sweetgum were most susceptible to flashback. This study examines the unanticipated chemical effect of deadening adjacent stems surrounding residual leave trees in poorly drained soils. [ABSTRACT FROM AUTHOR]

Local knowledge about natural resources is increasingly crucial in formulating conservation strategies and activities. This study collects data regarding medicinal plant use from Sepahat and Tamiang village residents. A total of 100 participants were included in the study, consisting of 50 participants from the Sepahat and another 50 from the Tamiang. Respondents were selected using the Snowball sampling technique, which involved identifying a key individual, such as local leaders, to initiate recruitment of other respondents. The study's findings indicate that the inhabitants of Sepahat village utilize 36 plant species belonging to 24 families, while Tamiang villagers use 11 plant species belonging to eight families. In Sepahat village, the botanical components used for medication comprise 25% rhizomes, 8% bark, 22% fruit, 3% shoots, 34% leaves, and 8% stems. In contrast, Tamiang comprises 23% rhizomes, 16% bark, 15% fruit, and 46% leaves. The utilization of stems and bark has the potential to pose a threat to sustainability. Among various uses, it has been observed that approximately 33% in Sepahat and 27% in Tamiang can lead to plant mortality. Conservation initiatives have been undertaken for 71% of Sepahat and 67% of the utilized plant species in Taminag. Traditional medicines have been used for generations to treat various health conditions, such as back pain, bleeding, controlling cholesterol, coughs, dengue fever, and diabetes. While current use might not threaten the biosphere reserve, villagers must embrace sustainable harvesting techniques, including selective harvesting, replanting, and establishing community nurseries dedicated to cultivating medicinal plants [ABSTRACT FROM AUTHOR]

Measurements of resistance to embolism suggest that Cupressus sempervirens has a stem xylem that resists embolism at very negative water potentials, with 50% embolism (P50) at water potentials of approximately −10 MPa. However, field observations in a semi‐arid region suggest tree mortality occurs before 10% embolism. To explore the interplay between embolism and plant mortality, we conducted a controlled drought experiment involving two types of CS seedlings: a local seed source (S‐type) and a drought‐resistant clone propagated from a semi‐arid forest (C‐type). We measured resistance to embolism, leaf relative water content (RWC), water potential, photosynthesis, electrolyte leakage (EL), plant water loss, leaf hydraulic conductivity, and leaf non‐structural carbohydrate (NSC) content during plant dehydration and before rewatering. All measured individuals were monitored for survival or mortality. While the S‐ and C‐types differed in P50, transpiration, and mortality rates, both displayed seedling mortality corresponding to threshold values of 52–55% leaf RWC, 55% and 18.5% percent loss of conductivity (PLC) in the xylem, which corresponds to 48% and 37% average EL values for S and C types, respectively. Although C‐type C. sempervirens NSC content increased in response to drought, no differences were observed in NSC content between live and dead seedlings of both types. Our findings do not fully explain tree mortality in the field but they do indicate that loss of membrane integrity occurs before or at xylem water potential, leading to hydraulic failure. [ABSTRACT FROM AUTHOR]

Lianas are major contributors to tropical forest dynamics, yet we know little about their mortality. Using overlapping censuses of the lianas and trees across a 50 ha stand of moist tropical forest, we contrasted community-wide patterns of liana mortality with relatively well-studied patterns of tree mortality to quantify patterns of liana death and identify contributing factors. Liana mortality rates were 172% higher than tree mortality rates, but species-level mortality rates of lianas were similar to trees with 'fast' life-history strategies and both growth forms exhibited similar spatial and size-dependent patterns. The mortality rates of liana saplings (<2.1 cm in diameter), which represent about 50% of liana individuals, decreased with increasing disturbance severity and remained consistently low during post-disturbance stand thinning. In contrast, larger liana individuals and trees of all sizes had elevated mortality rates in response to disturbance and their mortality rates decreased over time since disturbance. Within undisturbed forest patches, liana mortality rates increased with increasing soil fertility in a manner similar to trees. The distinct responses of liana saplings to disturbance appeared to distinguish liana mortality from that of trees, whereas similarities in their patterns of death suggest that there are common drivers of woody plant mortality. [ABSTRACT FROM AUTHOR]

Sugarcane aphid has emerged as a major pest of sorghum recently, and a few sorghum accessions were identified for resistance to this aphid so far. However, the molecular and genetic mechanisms underlying this resistance are still unclear. To understand these mechanisms, transcriptomics was conducted in resistant Tx2783 and susceptible BTx623 sorghum genotypes infested with sugarcane aphids. A principal component analysis revealed differences in the transcriptomic profiles of the two genotypes. The pathway analysis of the differentially expressed genes (DEGs) indicated the upregulation of a set of genes related to signal perception (nucleotide-binding, leucine-rich repeat proteins), signal transduction [mitogen-activated protein kinases signaling, salicylic acid (SA), and jasmonic acid (JA)], and plant defense (transcription factors, flavonoids, and terpenoids). The upregulation of the selected DEGs was verified by real-time quantitative PCR data analysis, performed on the resistant and susceptible genotypes. A phytohormone bioassay experiment showed a decrease in aphid population, plant mortality, and damage in the susceptible genotype when treated with JA and SA. Together, the results indicate that the set of genes, pathways, and defense compounds is involved in host plant resistance to aphids. These findings shed light on the specific role of each DEG, thus advancing our understanding of the genetic and molecular mechanisms of host plant resistance to aphids. [ABSTRACT FROM AUTHOR]

Climate change is increasing the frequency of droughts and the risk of severe wildfires, which can interact with shrub encroachment and browsing by wild ungulates. Wild ungulate populations are expanding due, among other factors, to favorable habitat changes resulting from land abandonment or land‐use changes. Understanding how ungulate browsing interacts with drought to affect woody plant mortality, plant flammability, and fire hazard is especially relevant in the context of climate change and increasing frequency of wildfires. The aim of this study is to explore the combined effects of cumulative drought, shrub encroachment, and ungulate browsing on the fire hazard of Mediterranean oak woodlands in Portugal. In a long‐term (18 years) ungulate fencing exclusion experiment that simulated land abandonment and management neglect, we investigated the population dynamics of the native shrub Cistus ladanifer, which naturally dominates the understory of woodlands and is browsed by ungulates, comparing areas with (no fencing) and without (fencing) wild ungulate browsing. We also modeled fire behavior in browsed and unbrowsed plots considering drought and nondrought scenarios. Specifically, we estimated C. ladanifer population density, biomass, and fuel load characteristics, which were used to model fire behavior in drought and nondrought scenarios. Overall, drought increased the proportion of dead C. ladanifer shrub individuals, which was higher in the browsed plots. Drought decreased the ratio of live to dead shrub plant material, increased total fuel loading, shrub stand flammability, and the modeled fire parameters, that is, rate of surface fire spread, fireline intensity, and flame length. However, total fuel load and fire hazard were lower in browsed than unbrowsed plots, both in drought and nondrought scenarios. Browsing also decreased the population density of living shrubs, halting shrub encroachment. Our study provides long‐term experimental evidence showing the role of wild ungulates in mitigating drought effects on fire hazard in shrub‐encroached Mediterranean oak woodlands. Our results also emphasize that the long‐term effects of land abandonment can interact with climate change drivers, affecting wildfire hazard. This is particularly relevant given the increasing incidence of land abandonment. [ABSTRACT FROM AUTHOR]

Summary: Turgor loss point (TLP) is an important proxy for plant drought tolerance, species habitat suitability, and drought‐induced plant mortality risk. Thus, TLP serves as a critical tool for evaluating climate change impacts on plants, making it imperative to develop high‐throughput and in situ methods to measure TLP.We developed hyperspectral pressure–volume curves (PV curves) to estimate TLP using leaf spectral reflectance. We used partial least square regression models to estimate water potential (Ψ) and relative water content (RWC) for two species, Frangula caroliniana and Magnolia grandiflora. RWC and Ψ's model for each species had R2 ≥ 0.7 and %RMSE = 7–10. We constructed PV curves with model estimates and compared the accuracy of directly measured and spectra‐predicted TLP.Our findings indicate that leaf spectral measurements are an alternative method for estimating TLP. F. caroliniana TLP's values were −1.62 ± 0.15 (means ± SD) and −1.62 ± 0.34 MPa for observed and reflectance predicted, respectively (P > 0.05), while M. grandiflora were −1.78 ± 0.34 and −1.66 ± 0.41 MPa (P > 0.05).The estimation of TLP through leaf reflectance‐based PV curves opens a broad range of possibilities for future research aimed at understanding and monitoring plant water relations on a large scale with spectral ecophysiology. [ABSTRACT FROM AUTHOR]

In this study, greenhouse tests were conducted on 240 Fraxinus excelsior seedlings to investigate the simultaneous damage caused by thea pathogenic fungus and oomycetes. The experiment was performed under controlled conditions in the greenhouse of the Institute of Forest Research in Sękocin Stary (Poland). Three species of oomycetes were used for the experiment: Phytophthora plurivora, Phytophthora taxon hungarica, Phytophthora megasperma, and the fungus Hymenoscyphus fraxineus. Inoculations using the fungus were carried out on shoots and in plant pots in which the soil was mixed with the three Phytophthora species mentioned above, both simultaneously and separately, which made it possible to recognize the cumulative effect of the related plant infection. The aim of the study was to investigate the effect of phosphite-containing preparations on the health of common ash under conditions of threat to the roots by Phytophthora spp. and damage to the aerial parts of the plant by the fungus, as well as the possible occurrence of synergistic effects. Two types of protective preparations (Actifos and Phos60 of the nitrogen and potassium forms, respectively) were used. It was found that the inoculation of ash seedlings with the fungus H. fraxineus resulted in plant mortality, while the mixture of Phytophthora did not cause significant damage. It was confirmed that when pathogens coexist, a phenomenon occurs that leads to an acceleration in the development of disease symptoms and, thus, to plant mortality. In vitro tests confirmed the usefulness of phosphite preparations for the protection of ash seedlings. [ABSTRACT FROM AUTHOR]

Background: Fusarium wilt caused by fungal pathogen, Fusarium oxysporum is one of the soil-borne diseases that cause 30 to 100% yield reduction with high plant mortality and severe problem in cowpea production. Methods: The Fusarium spp. isolate was obtained from infected cowpea plants and morphological and molecular characterization were done using universal primers. Similarity and phylogenetic evolutionary relationship analysis were performed with database. The fusarium wilt symptoms occurrence in each germplasm were scored using disease rating scale by artificial inoculation of 10% culture. Result: Isolated Fusarium spp. was an anamorphic species with medium growth rate (5 mm/day), characterised by white cottony to pinkish colonies, aseptate microconidia (12.879 X 3.570 µm) with false head, septate macroconidia (32.409 X 5.297 µm) along with chlamydospores. While, 90-100% homology was observed between isolate (Accession no: MZ706473) and fusarium reference database. Phylogenetic evolutionary analysis showed that the isolate was closely related to F. oxysporum (OL679453.1) strain supported by 52% bootstrap. Artificial screening of 115 cowpea germplasm under pot culture, identified 18 resistant lines with 0% symptoms. The wilting intensity was maximum during flowering or pod stage than seedling stage in cowpea. The identified resistant cowpea varieties could be used as donor parent in future resistant breeding programmes. [ABSTRACT FROM AUTHOR]

We present a representation of nitrogen and phosphorus cycling in the Functionally Assembled Terrestrial Ecosystem Simulator, a demographic vegetation model within the Energy Exascale Earth System land model. This representation is modular, and designed to allow testing of multiple hypothetical approaches for carbon‐nutrient coupling in plants. Novel model hypotheses introduced in this work include, (a) the controls on plant acquisition of aqueous mineralized nutrients in the soil and (b) fairly straight forward methods of allocating nutrients to specific plant organs and their losses through live plant turnover as well as litter fluxes generated through plant mortality. This combines the new with pre‐existing hypotheses (such as nitrogen fixation and soil decomposition) into a system that can accommodate plant‐soil dynamics for a large number of size‐ and functional‐type‐resolved plant cohorts within a time‐since‐disturbance‐resolved ecosystem. Root uptake of nutrients is governed by fine root biomass, and plants vary in their fine root biomass allocation in order to balance carbon and nutrient limitations to growth. We test the sensitivity of the model to a wide range of parameter variations and structural representations, and in the context of observations at Barro Colorado Island, Panama. A key model prediction is that plants in the high‐light‐availability canopy positions allocate more carbon to fine roots than plants in low‐light understory environments, given the widely different carbon versus nutrient constraints of these two niches within a given ecosystem. This model provides a basis for exploring carbon‐nutrient coupling with vegetation demography within Earth system models. Plain Language Summary: This work introduces a new set of nutrient cycling hypotheses incorporated into a terrestrial biosphere model. This includes the cycling of carbon, nitrogen and phosphorus, and focuses mainly on plant acquisition, allocation, and turnover. An analysis shows the model offers reasonable responses to perturbations in parameter constants and variability in climate forcing, considering its design balance between process complexity and parameterization burden. Key Points: The nutrient enabled ELM‐FATES model represents expected pattern responses to nutrient availability and parameter perturbationsThe model has been designed to introduce a reasonably small parameterization burdenThese hypothesis can capture some but not all elements of carbon‐nutrient dynamics and can be further inter‐compared with other hypotheses [ABSTRACT FROM AUTHOR]

With diseases and weeds alone accounting for approximately 30% of productivity losses in agriculture worldwide, plant diseases are a significant factor. Farmers frequently consult experts to diagnose their crops in an effort to reduce these losses. On the other hand, conventional visual assessment techniques focused on elements like leaf color, shape, and texture can be inefficient, time-consuming, and expensive. This study suggests using symptom traits like yellow leaves, black lesions, wilting, and plant mortality in crops like apple and grape to anticipate plant diseases, notably black rot. AlexNet, VGGNet, ResNet, and Inception are the four deep learning models examined in the study; VGGNet achieved the greatest accuracy of 98.19%. [ABSTRACT FROM AUTHOR]

Leaf blight spot disease, caused by bacteria and fungi, poses a considerable threat to commercial plants, manifesting as yellow to brown color spots on the leaves and potentially leading to plant mortality and reduced agricultural productivity. The susceptibility of jasmine plants to this disease emphasizes the necessity for effective detection methods. In this study, we harness the power of a deep convolutional generative adversarial network (DCGAN) to generate a dataset of jasmine plant leaf disease images. Leveraging the capabilities of DCGAN, we curate a dataset comprising 10,000 images with two distinct classes specifically designed for segmentation applications. To evaluate the effectiveness of DCGAN-based generation, we propose and assess a novel loss function. For accurate segmentation of the leaf disease, we utilize a UNet architecture with a custom backbone based on the MobileNetV4 CNN. The proposed segmentation model yields an average pixel accuracy of 0.91 and an mIoU (mean intersection over union) of 0.95. Furthermore, we explore different UNet-based segmentation approaches and evaluate the performance of various backbones to assess their effectiveness. By leveraging deep learning techniques, including DCGAN for dataset generation and the UNet framework for precise segmentation, we significantly contribute to the development of effective methods for detecting and segmenting leaf diseases in jasmine plants. [ABSTRACT FROM AUTHOR]

The use of high-performant varieties could help to improve the production of food legumes and thus meet the demand of the growing world population. However, long periods needed to develop new varieties through traditional breeding are a major obstacle. Thus, new techniques allowing faster genetic advance are needed. Speed breeding using longer periods of light exposure on plants, appears to be a good solution for accelerating plant life cycles and generation turnover. However, applying extended photoperiod causes plant stress and mortality due to lack of information on the adequate intensity to be used in speed breeding protocol. This study examines the impact of light intensity under speed breeding conditions on the development and growth of lentils and chickpeas, with a keen interest in enhancing genetic gain in these key food legumes. Four distinct levels of light intensity (T1: Green-house: 2000 µmol/m2/s; T2: 148–167 µmol/m2/s; T3: 111–129 µmol/m2/s; T4: 74–93 µmol/m2/s) under a photoperiod of 18 h of light and 6 h of darkness were tested in a growth chamber. Significant variation depending on light intensity was observed for plant height, total biomass, number of secondary stems, pods number, number of seeds per plant, growth rate, green canopy cover, time to flowering, time of pod set, time to maturity, vegetative stage length, reproduction stage length and seed filling stage length. Light intensity significantly influenced flowering/maturity and plant's stress compared to normal conditions in green-house where flowering/maturity were around 67/97 days for lentil and 79/111 days for chickpea. Therefore, lentils in treatment 2 flowered and reached maturity in 30/45 days respectively, with high stress, while chickpeas in the same treatment did not flower. In contrast, treatment 4 showed interesting results, promoting optimal growth with low stress, and flowering/maturity in 27/46 days and 28/54 days, respectively for lentils and chickpeas. These results underline the crucial importance of light management in speed breeding to accelerate vegetative growth and phenology while allowing healthy growth conditions for plants to produce enough seeds for generation turnover. [ABSTRACT FROM AUTHOR]

Background: Water deficit is one of the main drivers of plant mortality and is projected to be more critical owing to climate change. Because desiccation-tolerant vascular plants (DT plants) can cope with water deficit, the paradigm emerges of their strong association with and restricted occurrence to locations characterised by water deficit conditions. However, this paradigm is not supported by earlier studies, hampering our understanding of the species – environment relationships and the vulnerability of DT plants to climate change. Aims: We tested this paradigm and provide an evaluation of the vulnerability of DT plants to climate change. Methods: We estimated the diversity and distribution of DT plants along water deficit gradients and assessed species vulnerability to climate change from a climatic perspective and over broad phylogenetic and macroecological scales. Results: The diversity and distribution of DT plants were neither associated with, nor restricted to, locations characterised by water deficits. Species with narrow niche breadth and poikilochlorophylly might be the most vulnerable to climate change. Conclusions: Our findings suggest that the desiccation events DT plants undergo are promoted by topo-edaphic conditions rather than by climate. We suggest that ecologically restricted species and those with a poikilochlorophyllous strategy should be prioritised for conservation. [ABSTRACT FROM AUTHOR]

From 2005 to 2020, one-third of U.S. coal plants had at least one coal-fired generator close. We use this natural experiment to estimate the effect of coal plant exposure on mortality and house values. Using a difference-in-differences design, we find that counties within 30 miles of a closing unit experience large health effects after shutdown. While these health improvements appear to capitalize into housing values, they only do so within 15 miles of the plant and only when the retirement is of all units. Taken together, these results underscore the importance of risk salience in shaping market-mediated price effects. [ABSTRACT FROM AUTHOR]

Drought-induced plant mortality, resulting from either hydraulic failure or carbon starvation, is hypothesized to be modulated by the drought intensity. However, there is a paucity of research investigating the response strategies in desert shrubs under drought stress with different intensities. We transplanted potted Reaumuria soongorica (Pall.) Maxim. and Salsola passerina Bunge seedlings in the rain-out shelter, and implemented three water treatments: a control (well-watered, CK), a chronic drought (gradually less watered, CD), and a flash drought (not watered, FD). We then quantified plant physiological traits associated with water use and carbon assimilation. Both R. soongorica and S. passerina showed similar changes in water use and carbon characteristics under different drought treatments. Water use efficiency was not significantly changed, but embolism resistance was significantly lower in CD, and leaf specific conductivity and embolism resistance were significantly lower in FD compared to CK. Under the drought treatment, both shrubs had significantly lower hydraulic safety margins than CK, with FD being significantly lower than CD. Notably, FD had lower carbon assimilation and a lower leaf non-structural carbon concentration, but higher stem non-structural carbon concentration. The results of a principal component analysis showed that net photosynthetic rate, sapwood specific conductivity, embolism resistance, midday water potential, and leaf and stem soluble sugar concentration were the main axes of variation for R. soongorica traits. CK had the highest water use efficiency, net photosynthetic rate, and gas exchange rate, while FD had the lowest embolism resistance and highest osmoregulation. Midday water potential, leaf and stem soluble sugar concentration were the main axes of variation for S. passerina traits, and individual distribution under three water treatments was associated with drought tolerance traits. The findings suggest that species exhibit different response strategies for resistance to drought stress, with R. soongorica being drought-avoidant and S. passerina being drought-tolerant. These findings highlight the adaptive capacity of desert shrubs to water deficit and provide insights for assessing hydraulic failure and carbon starvation in desert shrubs. [ABSTRACT FROM AUTHOR]

Woody plants minimize xylem embolism formation during drought essentially by closing stomata at higher water potentials and/or by increasing the xylem resistance to embolism. Both of these mechanisms result in a higher stomatal safety margin (SSM), which is the water potential difference between stomatal closure and embolism formation. Here, we investigated whether increasing SSM represents a drought resistance mechanism for herbaceous plants and how the different water‐use strategies impact their survival. For that, we exposed four herbaceous crops with contrasting drought resistance to severe water deficit to assess drought‐induced damage and mortality. Unlike woody species, SSM was not associated with plant survival for herbaceous crops. Soybean, which presented the largest SSM across the four crops (1.67 MPa), exhibited the earliest mortality of leaves and whole plants as well as the highest rate of plant mortality (100%) at the end of the drought period. Cowpea, with an SSM of 0.63 MPa, was the most drought‐resistant species, with the latest leaf damage and the highest plant survival (100%). The most effective traits ensuring survival in herbaceous crops under severe drought were those related to drought avoidance mechanisms such as (1) early stomatal closure, (2) very low residual transpiration post‐stomatal closure, and (3) high capacitance pre‐ and post‐turgor loss. [ABSTRACT FROM AUTHOR]

Question: Drought‐induced tree mortality has been documented in forests worldwide but the mechanisms related to drought recovery are still poorly understood. To better predict forest trajectories under future climate scenarios, it is essential to disentangle physiological mechanisms underlying plant mortality caused by El Niño droughts. Here, we assessed how vegetation structure, vapor pressure deficit (VPD), and functional traits interact to mediate tree mortality after a severe drought in a tropical forest. Location: Mata das Flores State Park, an Atlantic Forest fragment in southeast Brazil. Methods: We established 20 permanent plots with contrasting vegetation structure and topography. In each plot, we measured tree abundance and diameter at breast height (DBH) of every woody plant (1–10 cm diameter) at the end of the drought, and two years after the break of drought, to calculate mortality rates during drought recovery. Hydraulic (e.g., maximum stomatal conductance to water vapor, stomatal density, etc.) and economic traits (specific leaf area, wood density, etc.) were measured on the 10 most abundant species. We also measured local air temperature and air humidity using HOBO dataloggers in each plot to calculate the VPD. Results: The studied Atlantic Forest understorey did not recover from the 2014–2016 drought, in terms of tree mortality. Lower VPD, driven by big trees in the valley, protected understorey plants with acquisitive economic attributes and conservative hydraulic attributes against mortality. On the other hand, higher VPD, driven by smaller trees and higher stem density on the ridge and slope, increased the mortality of understorey plants with acquisitive attributes. Conclusion: Ridges represent the most important fraction of the Atlantic Forest and our results suggest this type of forest is at high climate risk due to global change. Altogether, our results highlight that valleys are microclimate refuges for understorey plants and might help mitigate drought impacts in tropical forest under forecasted climate changes. [ABSTRACT FROM AUTHOR]

The natural distribution of Cycas micronesica includes three island groups. Damage to the widespread tree from the armored scale Aulacaspis yasumatsui was initiated with the 2003 invasion of Guam and the 2007 invasion of Rota. This herbivore has threatened the unique gymnosperm species with extinction. The number and identity of co-occurring consumers are dissimilar among disjunct insular subpopulations, and six of these habitats were used to assess tree mortality trends to confirm that A. yasumatsui stands alone as the greatest threat to species persistence. Following the initial infestation outbreak of this pest into each new subpopulation, the standing seedlings and saplings were the first to be culled, the juvenile plants were the next to be culled, and then the adult trees were killed more slowly thereafter. The timing of this plant population behavior did not differ among habitats with five other consumers, three other consumers, one other consumer, or no other consumers. We have shown that A. yasumatsui acting as the sole biotic threat in an isolated subpopulation can generate a decline in survival that is as rapid as when it is acting in conjunction with up to five other consequential consumers. This armored scale is the most acute threat to C. micronesica, and adding other specialist herbivores to the scale herbivory does not alter the speed and extent of initial plant mortality. [ABSTRACT FROM AUTHOR]

Regular spatial patterns of vegetation are a common sight in drylands. Their formation is a population-level response to water stress that increases water availability for the few via partial plant mortality. At the individual level, plants can also adapt to water stress by changing their phenotype. Phenotypic plasticity of individual plants and spatial patterning of plant populations have extensively been studied independently, but the likely interplay between the two robust mechanisms has remained unexplored. In this paper, we incorporate phenotypic plasticity into a multi-level theory of vegetation pattern formation and use a fascinating ecological phenomenon, the Namibian "fairy circles," to demonstrate the need for such a theory. We show that phenotypic changes in the root structure of plants, coupled with pattern-forming feedback within soil layers, can resolve two puzzles that the current theory fails to explain: observations of multi-scale patterns and the absence of theoretically predicted large-scale stripe and spot patterns along the rainfall gradient. Importantly, we find that multi-level responses to stress unveil a wide variety of more effective stress-relaxation pathways, compared to single-level responses, implying a previously underestimated resilience of dryland ecosystems. [ABSTRACT FROM AUTHOR]

Accidental herbicide drift onto neighboring crops, such as soybeans, can seriously harm non-target plants, affecting their growth and productivity. This study examined the impact of simulated drift from ten different herbicides (2,4-D, dicamba, glyphosate, saflufenacil, oxyfluorfen, hexazinone, diuron, diquat, nicosulfuron, and isoxaflutole) on young soybean plants. These herbicides were applied at three simulated drift levels (1/4, 1/16, and 1/32) equivalent to recommended commercial doses, and the resulting symptoms were carefully evaluated. Simulated drift caused distinctive symptoms, including chlorosis, twisting, necrosis, and growth abnormalities, varying depending on each herbicide's mode of action. Dicamba proved more toxic than 2,4-D, and symptom severity increased with drift proportion, with all herbicides causing over 30% injury at the 1/16 proportion. Notably, 2,4-D, dicamba, glyphosate, hexazinone, and diquat exceeded the half-maximal inhibitory concentration (IC50) value, significantly reducing total biomass. Dicamba consistently caused 50% injury at all proportions, while hexazinone, at the highest dose proportion, led to plant mortality. Dicamba also had biomass accumulation beyond the growth reduction (GR50), whereas hexazinone exhibited less than 10% accumulation due to its capacity to induce plant mortality. This study emphasizes the importance of understanding herbicide drift effects on non-target crops for more effective and safe weed management strategies. [ABSTRACT FROM AUTHOR]

Prolonged and/or intense drought leads to the deterioration of plant water balance, inducing embolism formation in the water conducting system, the xylem. The consequent loss of water transport capacity from roots to leaves (hydraulic failure) has been proposed as a main driver of plant mortality. Substantial inter- and intra-specific variation of resistance to embolism formation has been reported in plants. Hence, screening of different species/individuals is key to project the impact of future climate on ecosystems, while supporting breeding and reforestation. This review seeks to explain the mechanisms of water transport in plants and the phenomenon of embolism formation under drought stress by using concise and straightforward scholarly language. The main aim is to introduce non-expert readers (students, nonacademics, and academics from different scientific fields) to plant hydraulics and the controversial world of methods for measuring the vulnerability to embolism formation. To convey the message in full, we provide ranges of water potential values and widely used drought resistance indexes characterizing plants from different biomes. Various established methods used worldwide to monitor hydraulic efficiency under stress and measure hydraulic vulnerability by means of curves of different plant organs are introduced. Both classical widely used destructive methods and current non-destructive techniques, which have been gaining momentum in the last decade, are described. The main advantages and disadvantages of each method are briefly discussed to support decisions and selection of the most suitable method in experimental practice. [ABSTRACT FROM AUTHOR]

Purpose: Drought induces mortality in plants; however, how symbioses mediate the plant drought response remains understudied and may be crucial to understanding how shifts in symbioses under climate change scenarios may impact plant drought induced mortality. Methods: Drought was experimentally imposed in parallel on two legume hosts, Acmispon strigosus and Lotus japonicus, whose roots are nodulated by nitrogen fixing rhizobia in different genera. Within each host taxon, greenhouse experiments factorially combined legume genotypes varying in root nodule investment with rhizobia varying in nitrogen fixation capacity, to investigate how costs and benefits of symbiosis modulate plant performance under drought. Results: Net benefits of symbiosis with nitrogen fixing symbionts, namely increased number of leaves and shoot mass, were maintained under drought irrespective of nodulation level or host species, mitigating the carbon strain during drought. Net benefits of symbiosis occurred despite increased water cost associated with the maintenance of nitrogen fixation, costs that were evident even in pre drought baseline conditions. Conclusion: Our results demonstrate that benefits of root nodule symbiosis can be robust to environmental perturbations, and potentially mediate carbon starvation during drought induced mortality events. The investment in symbiosis and its impacts on biomass suggest that in long term droughts legumes may be more limited by carbon than water. Ongoing stability of these associations is predicted, even under extended drought conditions. [ABSTRACT FROM AUTHOR]

Heterobasidion species are the most important pathogens causing root and stem rot on conifers in northern hemisphere forests. The host list of this complex is very wide and includes over 200 species of trees and shrubs. Among the members of this complex, Heterobasidion annosum s. s. has the largest host range. In this study, young plants of Pinus sylvestris, Picea orientalis, Abies nordmanniana, Cedrus libani and Pinus brutia (three different origins) were inoculated on the lower stem with known genets of Heterobasidion annosum s.s. collected from Pinus brutia stands in south‐western Türkiye. Infection frequency, assessed as presence of the conidial stage in stem discs following incubation, in the inoculated seedlings was 100%. The Heterobasidion annosum s. s. isolates were re‐isolated from all inoculated host species. Control seedlings showed no symptoms of disease. Mortality in inoculated plants was 11.5% of the 735 inoculated plants, which died over an 8‐weeks incubation period. The isolates showed greater growth on Cedrus libani, Pinus sylvestris and Picea orientalis seedlings compared to other species tested. On the other hand, it was found that the least affected seedlings were Pinus brutia TB12 and Abies nordmanniana. This study proved that differences occur in aggressiveness of Heterobasidion annosum s. s. to host species. A striking point in the results is that, despite being the host species from which the isolates were obtained, Pinus brutia seedlings showed lower sensitivity to Heterobasidion annosum s. s. than the other conifer species tested. Inoculations of three different Pinus brutia provenances suggested there was no significant difference in mean lesion lengths and fungal growth values in Pinus brutia plants, except in Pinus brutia TB14, which was more susceptible to extension growth of the pathogen. [ABSTRACT FROM AUTHOR]

Premise: Life span varies greatly across plants, with some species being capable of extreme longevity. Yet even long‐lived individuals are susceptible to climatic events, fire, and other challenges. We examined rare mortality events and their causes in two long‐lived palmettos over four decades. Methods: We monitored the survival of the clonal Serenoa repens and non‐clonal, Florida‐endemic Sabal etonia from 1981 to 2022 in four habitats along an elevational gradient within the globally imperiled Florida scrub ecosystem. We considered several challenges to palmetto survival, including extreme fires, shading due to lack of fire, droughts, periods of high precipitation, and possible pathogens. Results: Survival of palmettos was remarkably high, and mortality was infrequent (Serenoa: cumulative, 5.7%; annualized, 0%–0.68%; Sabal: cumulative, 3.5%; annualized, 0%–0.43%). Mortality was highest in higher‐elevation habitats with greater soil drainage, and smaller palmettos were more likely to die. When subjected to extreme fire, Serenoa suffered greater mortality than Sabal. Mortality in long‐unburned habitats with increased shading rivaled that which occurred with extreme fire. There was no evidence of mortality due to lethal bronzing palm disease. Conclusions: Both palmettos had exceptionally low mortality rates, which, coupled with earlier work showing slow rates of transition from seedling to adult and remarkable adult longevity, suggest notably low rates of population turnover. Observed mortality in long‐unburned habitats suggests the importance of fire‐management planning with prescription burning. Lengthy age to reproduction and/or dependency on clonal propagation limits migration or genetic adaptation to altered conditions caused by climate change. [ABSTRACT FROM AUTHOR]

Vegetation can have a particularly strong effect on hydraulics and processes in dryland, ephemeral channels, where plants often occupy the channel bed. To understand the hydraulics, feedback effects and ecological dynamics for use in modelling and management, data on flow effects and vegetation dynamics are needed. Evidence from sites in southeast Spain, monitored for decades, is analysed here in relation to an extreme flood in September 2012 to identify thresholds for damage and destruction of plants, to assess rates of recovery, and to quantify effects of varying vegetation density and height on channel hydraulics. Repeated quadrat measurements provide data on vegetation cover, health and heights of plants, and were analysed in relation to measured flow stage and cross-section topographic surveys before, after and since the 2012 flood. Much of the vegetation was destroyed in the flood event, including the dominant Retama, resetting the vegetation. Threshold levels of shear stress for mortality and removal of the plants have been calculated. Rates of recovery have varied spatially, with little regrowth in main channels or on elevated floodplains, but strong growth occurring on bars. The different degrees of vegetation cover and height are calculated to have a very large effect on the flow hydraulics. The results support the proposal that dense vegetation cover can be highly effective in channel management by slowing flow, reducing erosion and increasing sedimentation. [ABSTRACT FROM AUTHOR]

In terrestrial ecosystems, the activities of semi‐fossorial animals such as Cape porcupines have important landscape effects that may manifest in the dry season when the availability of above‐ground forage becomes limiting. We investigated the effects of foraging activities of Cape porcupines on savanna landscapes. We measured the size (surface area and depth) of foraging holes of porcupines located at the base of trees in the dry season in two mesic savanna sites at Roodeplaat Farm and Bisley Valley Nature Reserve in South Africa. We also recorded plant and animal activities inside the foraging holes for 3 months. The depth of foraging holes beneath small trees (Vachellia nilotica) was greater than depths beneath old trees (V. robusta and D. rotundifolia). This resulted in the subsequent death of most (>50%) small impacted trees in the dry season at Bisley. The surface area of foraging holes for older trees was greater than that for small trees and even greater for old holes. This study showed that porcupines kill trees or expose them to secondary attacks. The physical impacts of semi‐fossorial herbivores in savannas can be significant, with contributions to direct and indirect landscape transformation and restoration. [ABSTRACT FROM AUTHOR]

The field survey conducted in Rajasthan, India, unveiled the widespread occurrence of Fusarium wilt in cumin fields that have been continuously cultivated for approximately 4 to 5 years. The incidence of this disease exceeded 30%, affecting cumin plants at all stages of growth, with severe symptoms ultimately resulting in the complete mortality of the plants. In laboratory studies, a bacterial isolate known as Bacillus licheniformis (CSR-D4) exhibited remarkable in vitro effectiveness, significantly inhibiting Fusarium oxysporum f.sp. cumnini (FOC) mycelial growth by an impressive 79.85%. In controlled pot experiments, cumin plants treated with B. licheniformis (CSR-D4) displayed milder symptoms than untreated plants, demonstrating a notably higher tolerance level, with only a 15% disease incidence as opposed to 90% in untreated plants. Further analysis of defense enzymes revealed elevated chlorophyll, carotenoid, peroxidase activity levels, and proline content in cumin plants treated with B. licheniformis (CSR-D4). Field assessments confirmed the efficacy of this bacterial isolate, as it successfully suppressed wilt incidence by 60%, significantly increased crop yield by 71.16%, and promoted root and shoot growth. Notably, applying B. licheniformis (CSR-D4) did not negatively impact beneficial microorganisms, and no adverse phytotoxic symptoms were observed. This study underscores the considerable potential of B. licheniformis (CSR-D4) in managing Fusarium wilt, offering an environmentally friendly and highly effective solution to enhance the health and productivity of pea plants. [ABSTRACT FROM AUTHOR]

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Management of storage pest insects relies heavily on chemical control, and there is a need to develop more sustainable management practices. Here, we evaluated the impact of 2% ethanol plant extracts of Ajuga reptans L., Ajuga pyramidalis L. (both Lamiaceae), Urtica dioica L. (Urticaceae), and Cannabis sativa L. (Cannabaceae) plants on mortality, population growth, and developmental stability [measuring fluctuating asymmetry (FA)] of the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae), a worldwide stored product pest. FA refers to small, random deviations occurring between the left and right sides of bilaterally symmetrical organisms; these deviations increase in response to environmental stress, making FA a reliable method to measure the impact of stress. FA was measured by means of geometric morphometrics, a method that allows for analyzing the whole landmark configuration of the insect, rather than taking single measurements. Extracts of the mentioned plants were used to treat maize (Zea mays L., Poaceae) kernels on which experimental populations of the rice weevil were grown, and we assessed mortality after 24–72 h, population growth after 30–90 days, and developmental stability after 90 days. Screening bioassays showed that S. oryzae adults were most affected by Ajuga extracts; Ajuga spp., especially A. reptans, significantly reduced population growth. In concordance, Ajuga extracts increased FA. The effects of U. dioica and C. sativa extract were less pronounced. None of the extracts significantly affected insect mortality. Overall, it can be concluded that A. reptans and A. pyramidalis are potential sources of bioactive compounds that may be further used for S. oryzae control. The results obtained confirm that variation in body shape asymmetry can be used as an indicator of population disturbance when insects are exposed to different types of stressors. [ABSTRACT FROM AUTHOR]

Frost is damaging to plants when air temperature drops below their tolerance threshold. The set of mechanisms used by cold‐tolerant plants to withstand freezing is called "hardening" and typically take place in autumn to protect against winter damage. The recent incorporation of a hardening scheme in the demographic vegetation model FATES opens up the possibility to investigate frost mortality to vegetation. Previously, the hardening scheme was used to improve hydraulic processes in cold‐tolerant plants. In this study, we expand upon the existing hardening scheme by implementing hardiness‐dependent frost mortality into CLM5.0‐FATES to study the impacts of frost on vegetation in temperate and boreal sites from 1950 to 2015. Our results show that the original freezing mortality approach of FATES, where each plant type had a fixed freezing tolerance threshold—an approach common to many other dynamic vegetation models, was restricted to predicting plant type distribution. The main results emerging from the new scheme are a high autumn and spring frost mortality, especially at colder sites, and increasing mid‐winter frost mortality due to global warming, especially at warmer sites. We demonstrate that the new frost scheme is a major step forward in dynamically representing vegetation in ESMs by for the first time including a level of frost tolerance that is responding to the environment and includes some level of cost (implicitly) and benefit. By linking hardening and frost mortality in a land surface model, we open new ways to explore the impact of frost events in the context of global warming. Plain Language Summary: Frost can lead to partial or full mortality of a plant, unless it has evolved a tolerance to cold weather to avoid the formation of ice crystals in its tissues. Frost mortality is poorly represented in most advanced dynamic vegetation models, which are our primary tools for predicting climate change and to understand its effects on the biosphere. In one of those models, the functionally assembled simulator (FATES), a minimum temperature threshold is assigned to each plant type to represent the limit at which it will start to incur frost injury. In this study, we focus on making the fixed temperature threshold of FATES variable in time and space—depending on the local conditions of temperature and light. Our results show that the new frost mortality scheme can simulate autumn and spring frost mortality, also for cold‐adapted species, and increases mid‐winter frost mortality due to variable winter weather—especially at warmer sites. This is in contrast to the original frost mortality scheme, which was only applicable to predict the distribution of plant types across climate zones. The implementation presented here opens up new ways to explore the spatial evolution of frost occurrences and intensities under changing climatic conditions. Key Points: We compare the original freezing mortality implementation in FATES (based on hard‐coded temperature thresholds) to a more dynamic approach (based on hardening)In contrast to the original approach, a new frost scheme is able to predict the damaging effects of extreme winter events and late spring frost eventsWe show that autumn and spring frost mortality is large, especially at colder sites, and that mid‐winter frost mortality increases with global warming [ABSTRACT FROM AUTHOR]

The effects of different defoliation levels caused by leaf-cutting ants have not yet been evaluated in Eucalyptus benthammii Maiden et Cambage and Eucalyptus dunnii Maiden plants. The aim of this study was to evaluate the losses caused by different defoliation levels on E. benthammii and E. dunnii plants artificially defoliated 30 days after planting, simulating Acromyrmex attacks. Four treatments were evaluated: 0: control, 1: 50%, 2: 75%, and 3, 100% defoliation. Plant height and diameter were recorded at 6, 12, 24, 36 and 72 months after planting. At six months, height and diameter of E. bentammii plants subjected to 100% defoliation differed significantly from control plants, however no significant differences in plant height and diameter were seen after 12 months. In E. dunnii, 100% defoliation resulted in significant plant mortality, and plants that survive this level of defoliation had significant losses in their development. In case of Acromyrmex attack on eucalyptus plants at 30 days after planting, it is suggested to replant E. dunnii 100% defoliated to avoid losses in the end of the forest cycle. In E. benthammii plantations, it is suggested to evaluate the vigor of the 100% defoliated seedlings, as they can recover over time. Only 100% defoliation can lead to losses in Eucalyptus plant growth. However, regionalized studies are necessary to assess the losses that intense defoliation can cause in each situation and in each plant species, as some species, such as E. benthammii, can recover along time. [ABSTRACT FROM AUTHOR]

Combined infection of the host plant with pathogens involving different parasitic lifestyles may result in synergistic effects that intensify disease symptoms. Understanding the molecular dynamics during concurrent infection provides essential insight into the host response. The transcriptomic pattern of cucumber plants infected with a necrotrophic pathogen, Pythium spinosum, and a biotrophic pathogen, Cucumber green mottle mosaic virus (CGMMV) was studied at different time points, under regimes of single and co-infection. Analysis of CGMMV infection alone revealed a mild influence on host gene expression at the stem base, while the infection by P. spinosum is associated with drastic changes in gene expression. Comparing P. spinosum as a single infecting pathogen with a later co-infection by CGMMV revealed a rapid host response as early as 24 hours post-CGMMV inoculation with a sharp downregulation of genes related to the host defense mechanism against the necrotrophic pathogen. Suppression of the defense mechanism of co-infected plants was followed by severe stress, including 30% plants mortality and an increase of the P. spinosum hyphae. The first evidence of defense recovery against the necrotrophic pathogen only occurred 13 days post-viral infection. These results support the hypothesis that the viral infection of the Pythium pre-infected plants subverted the host defense system and changed the equilibrium obtained with P. spinosum. It also implies a time window in which the plants are most susceptible to P. spinosum after CGMMV infection. [ABSTRACT FROM AUTHOR]

Plant health care is the science of anticipating and diagnosing the advent of life‐threatening diseases in plants. The fatality rate of plants can be reduced by diagnosing them for any signs early on. The early detection of such diseases is one possibility for lowering plant mortality rates. Machine learning (ML), a type of artificial intelligence technology that allows researchers to enhance and develop without being explicitly programmed, is used in this study to build early prediction models for plant disease diagnosis. Due to the similarities of crops throughout the early phonological phases, crop classification has proved problematic. ML can be applied to a variety of tasks recognize different types of crops at low altitude platforms with the help of drones that provide high‐resolution optical imagery. The drones are employed to photograph phonological stages, and these greyscale photographs are then utilized to develop grey level co‐occurrence matrices‐based characteristics. In this article, the proposed plant disease detection models are developed using ML approaches such as random forest‐nearest neighbours, linear regression, Naive Bayes, neural networks, and support vector machine. The performance of the generated plants disease risk evaluation model is calculated using unbiased metrics such as true positive rate, true negative rate, precision, recall, and F1‐score method are all factors to consider. The results revealed that the ensemble plants disease model outperforms the other proposed and developed plant disease detection models. The proposed and developed plant disease prediction models aimed to predict disease detection in the early stages, allowing for early preventive actions and predictive maintenance. [ABSTRACT FROM AUTHOR]

Summary: Lightning is an important agent of plant mortality and disturbance in forests. Lightning‐caused disturbance is highly variable in terms of its area of effect and disturbance severity (i.e. tree damage and death), but we do not know how this variation is influenced by forest structure and plant composition.We used a novel lightning detection system to quantify how lianas influenced the severity and spatial extent (i.e. area) of lightning disturbance using 78 lightning strikes in central Panama.The local density of lianas (measured as liana basal area) was positively associated with the number of trees killed and damaged by lightning, and patterns of plant damage indicated that this occurred because lianas facilitated more electrical connections from large to small trees. Liana presence, however, did not increase the area of the disturbance. Thus, lianas increased the severity of lightning disturbance by facilitating damage to additional trees without influencing the footprint of the disturbance.These findings indicate that lianas spread electricity to damage and kill understory trees that otherwise would survive a strike. As liana abundance increases in tropical forests, their negative effects on tree survival with respect to the severity of lightning‐related tree damage and death are likely to increase. [ABSTRACT FROM AUTHOR]