Search

Explanation of natural phenomena at one level of biological organisation almost always involves causes that are found at other levels. Although scientists thinking across levels find it easy to explain physiological phenomena, students often perceive this as a challenge. We developed a new graphic organiser called Zoom Map, which is a mode for structuring biological information along the levels of biological organisation and is designed to guide biology students when they need to consider the levels of organisation. The aim of this study is to examine how Zoom Map helps students explain a common phenomenon in plant physiology: leaves that are upright or wilted. Accordingly, we designed a teaching experiment covering 13 students. During the experiments, the students were videotaped. We used qualitative content analysis to examine the explanations. Our findings indicate that Zoom Map improved students' explanations of the phenomenon across multiple levels of organisation: The students used more levels than before, and they referred to lower levels that were lacking previously. Therefore, it can be concluded that students who use Zoom Map are supported in their ability to explain a biological phenomenon across the levels of biological organisation. [ABSTRACT FROM AUTHOR]

Summary: In plants, growth and defence are controlled by many molecular pathways that are antagonistic to one another. This results in a 'growth‐defence trade‐off', where plants temporarily reduce growth in response to pests or diseases. Due to this antagonism, genetic variants that improve resistance often reduce growth and vice versa. Therefore, in natural populations, the most disease resistant individuals are often the slowest growing. In crops, slow growth may translate into a yield penalty, but resistance is essential for protecting yield in the presence of disease. Therefore, plant breeders must balance these traits to ensure optimal yield potential and yield stability. In crops, both qualitative and quantitative disease resistance are often linked with genetic variants that cause yield penalties, but this is not always the case. Furthermore, both crop yield and disease resistance are complex traits influenced by many aspects of the plant's physiology, morphology and environment, and the relationship between the molecular growth‐defence trade‐off and disease resistance‐yield antagonism is not well‐understood. In this article, we highlight research from the last 2 years on the molecular mechanistic basis of the antagonism between defence and growth. We then discuss the interaction between disease resistance and crop yield from a breeding perspective, outlining the complexity and nuances of this relationship and where research can aid practical methods for simultaneous improvement of yield potential and disease resistance. [ABSTRACT FROM AUTHOR]

Understanding the short‐term responses of mesophyll conductance (gm) and stomatal conductance (gsc) to environmental changes remains a challenging yet central aspect of plant physiology. This review synthesises our current knowledge of these short‐term responses, which underpin CO2 diffusion within leaves. Recent methodological advances in measuring gm using online isotopic discrimination and chlorophyll fluorescence have improved our confidence in detecting short‐term gm responses, but results need to be carefully evaluated. Environmental factors like vapour pressure deficit and CO2 concentration indirectly impact gm through gsc changes, highlighting some of the complex interactions between the two parameters. Evidence suggests that short‐term responses of gm are not, or at least not fully, mechanistically linked to changes in gsc, cautioning against using gsc as a reliable proxy for gm. The overarching challenge lies in unravelling the mechanistic basis of short‐term gm responses, which will contribute to the development of accurate models bridging laboratory insights with broader ecological implications. Addressing these gaps in understanding is crucial for refining predictions of gm behaviour under changing environmental conditions. Summary statement: This review synthesises our current knowledge of short‐term responses of mesophyll conductance (gm) to changes in environmental conditions. Recent advances in measurement techniques for the detection of short‐term gm responses are described and points of caution are highlighted, such as the impact of vapour pressure deficit or when using stomatal conductance (gsc) as a proxy for gm. [ABSTRACT FROM AUTHOR]

An exponential rise in the atmospheric vapour pressure deficit (VPD) is among the most consequential impacts of climate change in terrestrial ecosystems. Rising VPD has negative and cascading effects on nearly all aspects of plant function including photosynthesis, water status, growth and survival. These responses are exacerbated by land–atmosphere interactions that couple VPD to soil water and govern the evolution of drought, affecting a range of ecosystem services including carbon uptake, biodiversity, the provisioning of water resources and crop yields. However, despite the global nature of this phenomenon, research on how to incorporate these impacts into resilient management regimes is largely in its infancy, due in part to the entanglement of VPD trends with those of other co‐evolving climate drivers. Here, we review the mechanistic bases of VPD impacts at a range of spatial scales, paying particular attention to the independent and interactive influence of VPD in the context of other environmental changes. We then evaluate the consequences of these impacts within key management contexts, including water resources, croplands, wildfire risk mitigation and management of natural grasslands and forests. We conclude with recommendations describing how management regimes could be altered to mitigate the otherwise highly deleterious consequences of rising VPD. Summary statement: Rising atmospheric vapour pressure deficit (or VPD) is one of the most widespread and significant consequences of climate warming for terrestrial ecosystems. This article reviews the mechanistic bases of these usually deleterious impacts and synthesises that information into a set of management recommendations to mitigate them. [ABSTRACT FROM AUTHOR]

The summer of 2022 has been the so far hottest summer on record in Central Europe. High temperatures negatively affect the physiology of plants and cause considerable thermal stress in particular on the leaf level. The assessment of the temperature-dependent decline of the quantum use efficiency of the photosystem II (Fv/Fm) has gained much popularity to quantify the leaf-level sensitivity to thermal stress. An open question is whether leaves heat to those in vitro estimated threshold temperatures on hot days or if plants can avoid heat stress through transpirational cooling. Therefore, leaf temperatures were monitored on a non-native Austrian oak (Quercus cerris) during a heatwave in July 2022 and compared to observed air temperature and leaf thermal traits assessed with a chlorophyll fluorometer. The highest air temperature recorded during the heatwave was 42.5 °C and surpassed the breaking point temperature (temperature at 5% decline of Fv/Fm; T5) by 0.3 °C, but was 6.1 °C lower than T50 (temperature at 50% decline of Fv/Fm). However, during the hottest day, the maximum leaf temperature was significantly below the air temperature. Even the directly illuminated leaf facing south reached a maximum temperature of only 38.7 °C but reached 39.8 °C on the second hottest day when the air temperature went up to 39.6 °C. All leaves showed a certain degree of homeothermy as the slope between leaf temperature and air temperature was 0.83 (P < 0.05). In conclusion, Austrian oak can buffer thermal stress during heatwaves to a certain degree, however, leaf temperatures are only marginally below critical threshold temperatures. [ABSTRACT FROM AUTHOR]

Maize cultivation is under the growing threat of charcoal rot (Macrophomina phaseolina). Chemical control of diseases imparts serious health hazards to humans and the ecosystem. Biochar as an alternative disease management approach has been under consideration of the researchers for some time now. The biochar utilized in this study was derived from maize stalks and cobs. Crystallographic structure, inorganic minerals content and size of maize biochar were analyzed by powder X-ray diffractometer, while scanning electron microscopy revealed rough, irregular, tubular structure of the biochar surface. EDX spectra revealed that the maize biochar composition was dominated by 'C' followed by 'O'. The current study was designed to determine the synergistic effect of maize biochar (MB), and biocontrol agent (BCA) Trichoderma viride as soil amendments on the suppression of M. phaseolina. In vitro bioassays were conducted to check the efficiency of antagonistic effect of Trichoderma spp., in combination with maize biochar. On the basis of maximum mycelial growth inhibition T. viride was selected for a glasshouse experiment. Maize plants were grown in pots containing a mixture of soil with MB at application at the rate of 3 and 6% (v/v) separately, associated with or without T. viride. Treatments amended with 3% MB inoculated with M. phaseolina significantly reduced the percentage disease severity index by 40%. While in the presence of T. viride, 3% MB showed maximum disease suppression and a minimum percentage severity index i.e. 60 and 20%, respectively. Highest nitrogen contents were 18.4 g kg−1 observed in treatment 6% MB, while highest phosphorus and potassium contents were 3.11 and 15.2 g kg−1, respectively in the treatment with 3% MB. Conclusively, the effect of variable concentrations of maize biochar and T. viride as soil amendment was evident on the development of charcoal rot, growth and physiology of maize plants. According to the available literature, our report is the first on the implementation of biochar in synergism with T. viride to suppress the charcoal rot in maize. [ABSTRACT FROM AUTHOR]

Chromium (Cr) is a toxic metal in soil–plant system, hence causing possible health risks prominently in the areas with forgoing industrial activities. Copper nanoparticles (Cu NPs) have been reported as an excellent adsorbent for pollutants. Therefore, this study investigates how copper nanoparticles enhance onion growth while decreasing chromium uptake in onion plants. Additionally, it examines the potential health risks of consuming onion plants with elevated chromium levels. The results demonstrated that the addition of CuNPs at 15 mg kg−1 significantly improved the plant height (48%), leaf length (37%), fresh weight of root (61%), root dry weight (70%), fresh weight of bulb (52%), bulb dry weight (59%), leaves fresh weight (52%) and dry weight of leaves (59%), leaf area (72%), number of onion leaves per plant (60%), Chl. a (42%), chl. b (36%), carotenoids (40%), total chlorophyll (40%), chlorophyll contents SPAD value (56%), relative water contents (35%), membrane stability index (16%), total sugars (25%), crude protein (21%), ascorbic acid (19%) and ash contents (64%) at 10 mg kg−1 Cr. Whereas, maximum decline of Cr by 46% in roots, 68% in leaves and 92% in bulb was found with application of 15 mg kg−1 of Cu NPs in onion plants under 10 mg kg−1 Cr toxicity. The health risk assessment parameters of onion plants showed minimum values 0.0028 for average daily intake (ADI), 0.001911 for Non-cancer risk (NCR), and 0.001433 for cancer risk (CR) in plants treated with Cu NPs at 15 mg kg−1 concentration grown in soil spiked with 10 mg kg−1 chromium. It is concluded that Cu NPs at 15 mg kg−1 concentration improved growth of plants in control as well as Cr contaminated soil. Therefore, use of Cu NPs at 15 mg kg−1 concentration is recommended for improving growth of plants under normal and metal contaminated soils. [ABSTRACT FROM AUTHOR]

Plant diseases are caused by various microorganisms such as bacteria, fungi, viruses, and nematodes. These diseases impact crop growth, reduce produce quality, and lead to financial losses. Plant disease can be caused by single pathogens or by interactions called "disease complexes", involving two or more pathogens. In these cases, the disease severity caused by the pathogens combined is greater than the sum of the disease caused by each pathogen alone. disease complexes formed among plant-parasitic nematodes (PPNs) with bacteria, fungi, or viruses, can occur. PPNs either enhance the other pathogen incidence and severity or are necessary for disease symptoms to be expressed. PPNs can do so by being wounding agents, vectors, modifiers of plant biochemistry and physiology, or altering the rhizosphere microbiome. This review identifies several PPNs-plant pathogens disease complexes in crop production to discuss how understanding such interactions is key for improving management practices. [ABSTRACT FROM AUTHOR]

Arabidopsis thaliana possesses two different ion‐export mechanisms in the plastid inner envelope membrane. Due to a genome duplication, the transport proteins are encoded by partly redundant loci: K+‐efflux antiporter1 (KEA1) and KEA2 and mechanosensitive channel of small conductance‐like2 (MSL2) and MSL3. Thus far, a functional link between these two mechanisms has not been established. Here, we show that kea1msl2 loss‐of‐function mutants exhibit phenotypes such as slow growth, reduced photosynthesis and changes in chloroplast morphology, several of which are distinct from either single mutants and do not resemble kea1kea2 or msl2msl3 double mutants. Our data suggest that KEA1 and MSL2 function in concert to maintain plastid ion homeostasis and osmoregulation. Their interplay is critical for proper chloroplast development, organelle function, and plant performance. [ABSTRACT FROM AUTHOR]

SUMMARY: Plants continuously endure unpredictable environmental fluctuations that upset their physiology, with stressful conditions negatively impacting yield and survival. As a contemporary threat of rapid progression, global warming has become one of the most menacing ecological challenges. Thus, understanding how plants integrate and respond to elevated temperatures is crucial for ensuring future crop productivity and furthering our knowledge of historical environmental acclimation and adaptation. While the canonical heat‐shock response and thermomorphogenesis have been extensively studied, evidence increasingly highlights the critical role of regulatory epigenetic mechanisms. Among these, the involvement under heat of heterochromatic suppression mediated by transcriptional gene silencing (TGS) remains the least understood. TGS refers to a multilayered metabolic machinery largely responsible for the epigenetic silencing of invasive parasitic nucleic acids and the maintenance of parental imprints. Its molecular effectors include DNA methylation, histone variants and their post‐translational modifications, and chromatin packing and remodeling. This work focuses on both established and emerging insights into the contribution of TGS to the physiology of plants under stressful high temperatures. We summarized potential roles of constitutive and facultative heterochromatin as well as the most impactful regulatory genes, highlighting events where the loss of epigenetic suppression has not yet been associated with corresponding changes in epigenetic marks. Significance Statement: High temperatures pose a major threat to plant physiology. While research has extensively focused on thermomorphogenesis and heat‐shock stress responses, the roles of epigenetic mechanisms remain relatively under‐explored. In particular, the contribution of transcriptional gene silencing (TGS) is probably the least studied. Our review highlights how canonical TGS and heterochromatin dynamics may contribute to plant heat tolerance, summarizing both established and novel insights. With this work, we aim to promote alternative avenues for eventually developing heat‐resistant crops, ultimately contributing to more sustainable agriculture under a global warming scenario. [ABSTRACT FROM AUTHOR]

Water deficit priming through regulated deficit irrigation has been shown to be beneficial for peanut cultivation, leading to improved water‐use efficiency during the crop cycle and enhanced stress acclimation. The effects of priming using water deficit can be heritable, but little is known about stress priming effects on the physiology and growth of successive generations undergoing water stress. Two experiments were conducted to assess cross‐generational priming by determining physiological and growth responses of offspring of primed and non‐primed peanut plants of two genotypes, COC‐041 and New Mexico Valencia C (NMV‐C), both previously found to be strongly responsive to priming. Seeds were collected from parental plants subjected to mild water stress by regulated deficit irrigation (primed) or adequate irrigation (non‐primed). These seeds were then planted, and the offspring were monitored for physiological and growth responses to water stress, including on a whole‐plant basis using a high‐throughput physiological phenotyping platform and on individual leaves by periodic single‐leaf measurements. Measurements included whole‐plant transpiration (plant‐Tr), root water uptake, leaf transpiration, stomatal conductance and net CO2 assimilation (leaf‐Tr, leaf‐gs, and leaf‐A), leaf water and osmotic potential (leaf‐Ψw and leaf‐Ψo), leaf osmotic adjustment, leaf relative water content (leaf‐RWC) and cumulative plant‐Tr. Offspring of both genotypes from primed parent plants had faster early establishment, with more uniform germination, and more rapid initial seedling growth compared to offspring from non‐primed parent plants. Although offspring of both non‐primed and primed plants of both genotypes exhibited a significant reduction of plant‐Tr, gas exchange, leaf‐Ψw, leaf‐Ψo, and leaf‐RWC when exposed to water stress, offspring of primed plants showed increased water use efficiency through reduced leaf‐gs, leaf‐Tr and plant‐Tr while maintaining leaf‐A under water stress. Despite offspring of both primed and non‐primed plants being susceptible to severe water stress, offspring of primed plants exhibited overall enhanced water use efficiency, leading to greater dry biomass production per gram of transpired water and a trend of less growth reduction due to water stress compared to offspring of non‐primed plants, especially for the genotype COC‐041. This study shows the potential of water deficit priming to promote cross‐generational changes in physiological function under limited water availability, by enhancing crop stress acclimation in the next plant generation. [ABSTRACT FROM AUTHOR]

Background: With the rapid proliferation of online education, it is incumbent upon teachers to find ways to provide online students with science laboratory experiences. Existing research on online labs focuses heavily on computer‐supported inquiry learning environments, such as virtual laboratories and remote laboratories. There are limited studies on kitchen labs or home labs. Objectives: This study investigated the effectiveness of home labs using lab kits from two perspectives: students' perceptions and experiences of labs conducted in a home environment, as well as whether home labs help with students' knowledge acquisition. Methods: This study employed lab quizzes to assess students' performance and lab reports to evaluate students' ability to interpret the lab results accurately in the authentic home lab contexts. Surveys and semi‐structured interviews were used to collect students' perceptions and experience data regarding these hands‐on experiments at home. Results and Conclusions: We found that students' perceptions of home labs are similar to that of face‐to‐face labs, but they generally perceive home labs to be less complex. Students' performances on lab quizzes and lab reports indicate that the majority of them were able to apply the key scientific concepts to accurately interpret lab results in authentic home lab contexts. Students perceived that home labs provide flexibility and help in connecting learning to the real world. However, they also face challenges such as unexpected results and ambiguity during the process. Implications: Based on the key findings from this study and our reflections, four practice guidelines were provided for teaching hands‐on experiments online. Lay Description: What is already known about this topic: Science‐laboratory activities play a critical role in science education. The lack of best practices for teaching science laboratory activities online has become one of the most significant barriers to online education.Existing online labs research focuses heavily on computer‐supported inquiry learning environments, such as virtual laboratories and remote laboratories. There are limited studies on kitchen labs or home labs and some research has mainly an exploratory nature. What this paper adds: The value of authentic hands‐on learning experience is more than the acquisition of laboratory design skills, but also the acquisition of problem‐solving skills in real‐world.This study reported findings of the evaluation of hands‐on home laboratory activities in an online science course from both students' perception and their knowledge acquisition perspectives.This study also explored the benefits and challenges students faced in home labs. Implication for practice and/or policy: Practical guidance and implications for teaching and learning science online using laboratory activities were provided by sharing our experience and lessons learned through the whole process.We recommend that practitioners incorporate more scaffolding and peer collaboration opportunities as well as key concept reflection as teaching strategies to improve the effectiveness of home lab activities. [ABSTRACT FROM AUTHOR]

Water stress causes various plant morphological, physiological, and biochemical responses. Silicon application may reduce the water stress tolerance in plants by increasing the physiology parameters and the crop's vegetative growth. Hence, the study aims to evaluate the effect of water stress levels on Alternanthera sissoo, known as Brazilian spinach, and determine which silicon (Si) level is the best under water scarcity. The method implied measuring the water stress by different levels of water level applied to the plant which are 100 % (well-watered), 75 % (moderate water deficit), 50 % (high water deficit), and 25 % (severe water deficit). The variation of silicon concentrations is S0 (control), S1, S2 and S3 (0, 0.6, 0.9 and 1.2 %v/v) arranged in the Randomized Complete Block Design (RCBD) in the greenhouse. Growth, physiological, and biochemical parameters were analyzed during the experiment. The research findings showed that water stress results were statistically reduce the leaf area, leaf number root length, fresh weight, chlorophyll content, relative water content (RWC), and malondialdehyde (MDA). The root length, leaf area, and malondialdehyde (MDA) show the interaction between water stress level and silicon concentration. The study proposed that the Si nutrient management strategy has the potential to minimize the impacts of drought stress in Brazilian spinach. Regarding research findings, it was determined that the optimal water requirement for Alternanthera sissoo is 50 % of the water treatments, with a silicon concentration of 1.2 %v/v. This is essential for better water management of the plant. [ABSTRACT FROM AUTHOR]

Sensitive irrigation programming requires both a good knowledge of plant physiology regarding water use and the monitoring of the effect of water stress on plant physiology. In this study, the effect of different irrigation strategies on full-grown olive trees of the Memecik variety irrigated by the drip irrigation method was investigated over three crop seasons (2012–2013, 2013–2014, and 2014–2015), and the possibility of using these strategies in forming an irrigation program was examined. The experiment consisted of five irrigation treatments with three replications in a random block design. One significant finding after the three years of observation in the study was that it was possible to determine in a simple and sensitive way the temporal responses of olive trees under conditions of water stress with predawn plant water potential, stomatal conductance, and plant water stress index but not chlorophyll content (SPAD value). Statistically significant differences were found between the treatments in the measurements made. Taking into account the three-year averages of treatment values for water applications, acceptable threshold values for predawn plant water potential, stomatal conductance, and plant water stress index are −1.64 MPa , 330 mmol m−2 s−1 , and 0.37, respectively. It is easy to put these measurements into practice, and doing so will enable very significant water savings in Mediterranean climate conditions. [ABSTRACT FROM AUTHOR]

In recent decades, the interest of the scientific community in plant space biology increased based on the certainty that cultivating higher plants in space is imperative for prolonged human missions. The cultivation of plants in space assumes great relevance moved by the consideration that there is a pivotal need to improve resource regeneration and onboard production of plant-based food, thus reducing the supply of resources from Earth. Therefore, the hereby paper provides an overview on the evolution of the interest in plant space biology from 2000 to 2023, basing the search on specific keyword combinations. The study encompasses (i) a proper quantitative search on the Scopus database; (ii) keyword frequencies and clustering analysis, (iii) a keyword network and time-gradient analysis and (iv) an elaboration of knowledge gaps comparing our results and recent reviews. Results highlighted an increase in publications in the last 10 years and a specific time-gradient related shifting on subtopics such as in situ resource utilization (ISRU) application and food production in a space mission context. Currently, knowledge gaps were identified in four research areas related to water dynamics in extra-terrestrial environments, plant physiology and biochemistry in response to growth on regolith, interactions with fertilizers, and plant/soil microbiome. Identifying these gaps will allow to canalize future efforts of space research where needed, facing the unsolved questions. Our analysis pointed out that space plant biology turned out to be oriented towards short and long-term space mission applications for improving resource regeneration and onboard/extraterrestrial-grounded production of plant-based food, thereby diminishing reliance on Earth for resupply. • The scientific community's interest in plant space biology increased in the perspective of prolonged human missions. • The bibliometric analysis highlighted a general increase in publications in the last ten years. • Publications shifted their focus on subtopics such as ISRU application and food production in a space mission context. • Main identified knowledge gaps are water dynamics in space, plant growth on mars-like soils, and plant/soil microbiome. [ABSTRACT FROM AUTHOR]

Argania spinosa (L.) Skeels is an endemic species to Morocco that has multiple uses. It plays multiple important roles in terms of its botanical, ecological, and economic properties. However, the domestication of this species will open up considerable economic opportunities for Morocco. Here, for the first time, we assessed the effect of different doses of compost and NPK fertilizers on the vegetative growth parameters, biochemical and antioxidant potential of the Argania spinosa plant, and soil properties. Over a two-year period (2022–2023), eight different treatments were applied across two experimental sites. These treatments included the following: T0 (Control), T1 (F1-80.50.70 g NPK/plant), T2 (F1-125.75.100 g NPK/plant), T3 (F2-160.100.140 g NPK/plant), T4 (F2-250.150.200 g NPK/plant), T5 (F1-2.5 kg/plant compost), T6 (F1-5 kg/plant compost), T7 (F2-5 kg/plant compost), and T8 (F2-10 kg/plant compost), with F1 and F2 being the frequencies of application. We compared several doses of fertilizers with no fertilization as a control. The results showed a significant influence of the compost and NPK fertilizer on the vegetative growth parameters. For the Tamjlojt site, the first year is important because treatments T3 and T4 significantly increased height by 71.94 ± 21.15% and 74.31 ± 12.31%, respectively. For the circumference, the results showed a significant improvement by the treatments T4 and T3, and T1 demonstrated the highest gain. For the collar diameter, all treatments showed a significant difference. The most notable difference was observed with treatments T3 and T7 with 115.63 ± 33.88% and 101.09 ± 20.84%, respectively. For the Rasmouka site, the second year was the most important. The treatments with the most important height increase were T7 and T8, with a value of 43.14 ± 10.06% and 36.44 ± 9.95%; the same was observed for collar diameter as a significant increase was found in T8 and T7 with a value of 55.05 ± 15.7% and 54.08 ± 9.64%. For the circumference parameter, the treatments that increased significantly this parameter were T8 and T7 with a value of 53.36 ± 15.11% and 50.34 ± 11.29% in 2023. In addition, the highest content of carbohydrates was recorded for the treatment T3 with a value of 148.89 ± 8.11 (mg EG/g). For phenolic determination, the highest value was 2532 ± 457.13 (µg GAE/mL), shown for treatment T1. For flavonoids, the treatments that showed a significant effect were T1 and T6 with a value of 2261.98 ± 184.61 and 1237.70 ± 95.65 (µg QE/mL), respectively. For the impact on soil properties, the electrical conductivity, at the Tamjlojt site, treatment T1 showed a significant increase to 1139.00 ± 241.30 (ms/cm), while at the Rasmouka site, treatment T8 showed a significant increase to 303.33 ± 9.33 (ms/cm). Concerning organic carbon, all treatments resulted in increased percentages of this parameter in the soil. For the Tamjlojt site, the T7 treatment had a significant positive effect on this parameter with a value of 0.87 ± 0.12%. For the Rasmouka site, the T3 treatment increased the percentage of organic carbon with a value of 1.17 ± 0.07%. In addition, the organic matter content showed an improvement with a value of 2.02 ± 0.12%. As there are no previous studies in Argania spinosa fertilization, this study greatly contributes to our understanding of the benefits of using different fertilizers at different doses, in particular T8 and T7 as organic fertilizers and T3, T4 as chemical ones, on argan growth, the biochemical and antioxidant properties of leaves, and its soil properties. [ABSTRACT FROM AUTHOR]

Climate change presents numerous challenges for agriculture, including frequent events of plant abiotic stresses such as elevated temperatures that lead to heat stress (HS). As the primary driving factor of climate change, HS threatens global food security and biodiversity. In recent years, HS events have negatively impacted plant physiology, reducing plant's ability to maintain disease resistance and resulting in lower crop yields. Plants must adapt their priorities toward defense mechanisms to tolerate stress in challenging environments. Furthermore, selective breeding and long-term domestication for higher yields have made crop varieties vulnerable to multiple stressors, making them more susceptible to frequent HS events. Studies on climate change predict that concurrent HS and biotic stresses will become more frequent and severe in the future, potentially occurring simultaneously or sequentially. While most studies have focused on singular stress effects on plant systems to examine how plants respond to specific stresses, the simultaneous occurrence of HS and biotic stresses pose a growing threat to agricultural productivity. Few studies have explored the interactions between HS and plant–biotic interactions. Here, we aim to shed light on the physiological and molecular effects of HS and biotic factor interactions (bacteria, fungi, oomycetes, nematodes, insect pests, pollinators, weedy species, and parasitic plants), as well as their combined impact on crop growth and yields. We also examine recent advances in designing and developing various strategies to address multi-stress scenarios related to HS and biotic factors. [ABSTRACT FROM AUTHOR]

Introduction: Recent advancements in nanotechnology present promising opportunities for enhancing crop resilience in adverse environmental conditions. Methods: In this study, we conducted a factorial experiment to investigate the influence of potassium nanosilicate (PNS) on sorghum plants exposed to varying degrees of drought stress A randomized complete block design with three replications was employed to subject the sorghum plants to different drought conditions. The three levels of stress were designated as non-stress (NS at -0.03 MPa), moderate stress (MD at -0.6 MPa), and severe stress (SD at -1.2 MPa). The plants were administered PNS at concentrations of 0 mM (control), 3.6 mM Si, and 7.2 mM Si. Results and discussion: As drought stress intensified, we observed significant reductions in multiple plant parameters, including height, fresh weight, dry weight, leaf number, stem diameter, cluster length, seed weight, and nutrient uptake, with the most pronounced effects observed under SD conditions. Interestingly, nitrogen (N) and potassium (K) levels exhibited an increase under drought stress and PNS application, peaking at MD, alongside Si concentrations. Notably, PNS application facilitated enhanced nutrient uptake, particularly evident in the significant increase in nitrogen concentration observed at 3.6 mM PNS. Furthermore, the application of PNS significantly enhanced the fresh weight and nutrient concentrations (notably K and Si) in sorghum seeds under drought stress, despite varying statistical significance for other nutrients. These findings shed light on the mechanisms through which PNS exerts beneficial effects on plant performance under drought stress. By elucidating the complex interactions between PNS application, drought stress, and plant physiology, this study contributes significantly to the development of sustainable agricultural practices aimed at bolstering crop resilience and productivity in waterlimited environments. [ABSTRACT FROM AUTHOR]

Investigating functional traits among mountain species with differing altitude requirements is integral to effective conservation practices. Our study aims to investigate the structural and chemical characteristics of Daphniphyllum macropodum leaves at three altitudes (1100 m, 1300 m, and 1500 m) across southern China to provide insight into changes in leaf functional traits (LFT) as well as plant adaptations in response to changing environmental conditions. Leaf structural characteristics include leaf thickness (LT), leaf area (LA), specific leaf area (SLA), and leaf tissue density (LD), respectively, while chemical properties include carbon-nitrogen-phosphorus (C:N:P) contents and ratios, such as C/N, C/P, and N/P. Our findings demonstrated the significant effect of altitude on both structural (LT, SLA, LD) and chemical aspects (N, C/N, N/P) of LFT. In particular, leaves at 1100 and 1300 m differed greatly, with 1300 m having lower SLA values than 1100 m. Observable trends included an initial increase followed by a decline as the altitude rose. Notable among them were the LT, LD, N, and N/P values at both locations. Traits at 1300 m were significantly higher than at 1100 m; SLA and C/N values displayed an inverse trend, with their lowest values occurring at 1300 m. Furthermore, this research demonstrated various degrees of variation among LFT, with structural traits exhibiting greater fluctuation than chemical traits. Robust correlations were observed among certain traits, such as LT, LD, and SLA. Furthermore, the interdependency relationships between N and C/N, as well as P and C/P, demonstrated interconnectedness. Redundancy analysis indicated that soil factors, specifically P content, exerted the strongest impact on LFT. At 1100 m, D. macropodum employed acquisition strategies; however, at 1300 m, conservation strategies emerged, showing a shift from acquisition strategies at lower altitudes to conservative strategies at higher ones. [ABSTRACT FROM AUTHOR]

Solar‐induced fluorescence (SIF) is a proxy of ecosystem photosynthesis that often scales linearly with gross primary productivity (GPP) at the canopy scale. However, the mechanistic relationship between GPP and SIF is still uncertain, especially at smaller temporal and spatial scales. We deployed a ultra‐hyperspectral imager over two grassland sites in California throughout a soil moisture dry down. The imager has high spatial resolution that limits mixed pixels, enabling differentiation between plants and leaves within one scene. We find that imager SIF correlates well with diurnal changes in leaf‐level physiology and gross primary productivity under well‐watered conditions. These relationships deteriorate throughout the dry down event. Our results demonstrate an advancement in SIF imaging with new possibilities in remotely sensing plant canopies from the leaf to the ecosystem. These data can be used to resolve outstanding questions regarding SIF's meaning and usefulness in terrestrial ecosystem monitoring. Plain Language Summary: Estimating the rate of carbon uptake by vegetation across space and time remains a challenge. Solar‐induced fluorescence (SIF), the emission of light by vegetation during photosynthesis, has recently emerged as a potential estimate of carbon uptake in many ecosystems and is observable from both satellites and ground‐based sensors. Here we present results from a field campaign with a novel SIF instrument that creates images (akin to a photo) across a landscape, allowing for SIF measurements from individual leaves, plants, or areas of interest. We find that SIF retrievals from the imager correspond to seasonal variations in carbon dioxide fixation rates and leaf‐level physiology relating to photosynthesis. We use this novel technology to improve understanding of SIF and carbon uptake across spatial and temporal scales. Key Points: Novel imagery technology enables solar‐induced fluorescence (SIF) acquisition across space and timeSIF diurnal and seasonal variations correspond to carbon fluxes and environmental conditionsImaging capacity predicts leaf‐level physiology across leaf, plant, and landscape scales [ABSTRACT FROM AUTHOR]

Global climate change and the decreasing availability of high-quality water lead to an increase in the salinization of agricultural lands. This rising salinity represents a significant abiotic stressor that detrimentally influences plant physiology and gene expression. Consequently, critical processes such as seed germination, growth, development, and yield are adversely affected. Salinity severely impacts crop yields, given that many crop plants are sensitive to salt stress. Plant growth-promoting microorganisms (PGPMs) in the rhizosphere or the rhizoplane of plants are considered the "second genome" of plants as they contribute significantly to improving the plant growth and fitness of plants under normal conditions and when plants are under stress such as salinity. PGPMs are crucial in assisting plants to navigate the harsh conditions imposed by salt stress. By enhancing water and nutrient absorption, which is often hampered by high salinity, these microorganisms significantly improve plant resilience. They bolster the plant's defenses by increasing the production of osmoprotectants and antioxidants, mitigating salt-induced damage. Furthermore, PGPMs supply growth-promoting hormones like auxins and gibberellins and reduce levels of the stress hormone ethylene, fostering healthier plant growth. Importantly, they activate genes responsible for maintaining ion balance, a vital aspect of plant survival in saline environments. This review underscores the multifaceted roles of PGPMs in supporting plant life under salt stress, highlighting their value for agriculture in salt-affected areas and their potential impact on global food security. [ABSTRACT FROM AUTHOR]

Background: This study aimed to assess the methods used for ripening fruits by sellers and to examine the knowledge regarding the health risks associated with the use of calcium carbide (CaC2) among both fruit sellers and consumers in Ado-Ekiti. Methods: The study employed a cross-sectional design, utilizing a semi-structured questionnaire administered in major markets within Ado-Ekiti. Knowledge levels were categorized into good (> 70% score), fair (50–69% score), and poor (< 50% score). One way Analysis of variance (ANOVA) and Independent sample t-test was used to indicate knowledge score difference with respect to socio demographic characteristics. Results: The study involved 357 consumers and 20 fruit sellers, with a majority being females (54.9% of consumers; 80.0% of sellers) and aged predominantly between 18–27 years and 28–39 years. The findings revealed that the use of CaC2 (50%) and natural ripening methods (100%) were common among fruit sellers. Sellers cited cancer (60%), bacterial infections (35%), and chest tightness (15%) as associated risks with CaC2 usage. Similarly, consumers expressed concerns about consuming CaC2-ripened fruits, attributing risks such as abdominal burns (70%), cancer (70.6%), and diarrhoea (67.3%). A significant proportion of sellers (90%) exhibited poor knowledge regarding the risks associated with CaC2, while 24.6% of consumers demonstrated fair knowledge on the subject. Conclusion: The study identified common fruit ripening practices among sellers. Fruit sellers showed poor knowledge, while consumers displayed fair to poor understanding of health risks linked to calcium carbide use in artificial fruit ripening. [ABSTRACT FROM AUTHOR]

Droughts can affect ecosystem CO2 fluxes directly or indirectly by changing plant community composition. However, it is unknown whether shifts in plant community composition buffer or amplify the response of ecosystem CO2 fluxes to droughts with different seasonal timing, as plant phenology and physiology of the different plant functional types respond differently to droughts. To identify the interaction of drought timing and plant community composition in regulating ecosystem CO2 fluxes, we conducted a three‐year manipulative experiment in which extreme droughts occurring in the early, mid and late growing seasons were separately imposed on experimental plot communities comprising graminoids, shrubs and their combination in a semi‐arid grassland of Inner Mongolia, China. Overall, mid‐season drought caused the largest negative effects regardless of plant community composition. In addition to decreasing aboveground biomass, mid‐season drought suppressed fluxes by reducing leaf photosynthetic rate, while early‐season and late‐season drought reduced fluxes mainly by shortening growing season length. All three community compositions had consistent responses to early‐season and mid‐season droughts. However, ecosystem CO2 fluxes in the combination community were less negatively affected by late‐season drought than in either shrub or graminoid communities because the growing season length was shortened less. Synthesis. Our results highlight that it is important to account for interactions of seasonal timing and plant community composition when predicting magnitude and pathways of drought effects on ecosystem carbon cycling. [ABSTRACT FROM AUTHOR]

Soybean cultivation in tropical regions relies on symbioses with nitrogen-fixing Bradyrhizobium and plant growth-promoting bacteria (PGPBs), reducing environmental impacts of N fertilizers and pesticides. We evaluate the effects of soybean inoculation with different bacterial consortia combined with PGPBs or microbial secondary metabolites (MSMs) on rhizosoil chemistry, plant physiology, plant nutrition, grain yield, and rhizosphere microbial functions under field conditions over three growing seasons with four treatments: standard inoculation of Bradyrhizobium japonicum and Bradyrhizobium diazoefficiens consortium (SI); SI plus foliar spraying with Bacillus subtilis (SI + Bs); SI plus foliar spraying with Azospirillum brasilense (SI + Az); and SI plus seed application of MSMs enriched in lipo-chitooligosaccharides extracted from B. diazoefficiens and Rhizobium tropici (SI + MSM). Rhizosphere microbial composition, diversity, and function was assessed by metagenomics. The relationships between rhizosoil chemistry, plant nutrition, grain yield, and the abundance of microbial taxa and functions were determined by generalized joint attribute modeling. The bacterial consortia had the most significant impact on rhizosphere soil fertility, which in turn affected the bacterial community, plant physiology, nutrient availability, and production. Cluster analysis identified microbial groups and functions correlated with shifts in rhizosoil chemistry and plant nutrition. Bacterial consortia positively modulated specific genera and functional pathways involved in biosynthesis of plant secondary metabolites, amino acids, lipopolysaccharides, photosynthesis, bacterial secretion systems, and sulfur metabolism. The effects of the bacterial consortia on the soybean holobiont, particularly the rhizomicrobiome and rhizosoil fertility, highlight the importance of selecting appropriate consortia for desired outcomes. These findings have implications for microbial-based agricultural practices that enhance crop productivity, quality, and sustainability. [ABSTRACT FROM AUTHOR]

Understanding photosynthetic acclimation to elevated CO2 (eCO2) is important for predicting plant physiology and optimizing management decisions under global climate change, but is underexplored in important horticultural crops. We grew three crops differing in stomatal density—namely chrysanthemum, tomato, and cucumber—at near‐ambient CO2 (450 μmol mol−1) and eCO2 (900 μmol mol−1) for 6 weeks. Steady‐state and dynamic photosynthetic and stomatal conductance (gs) responses were quantified by gas exchange measurements. Opening and closure of individual stomata were imaged in situ, using a novel custom‐made microscope. The three crop species acclimated to eCO2 with very different strategies: Cucumber (with the highest stomatal density) acclimated to eCO2 mostly via dynamic gs responses, whereas chrysanthemum (with the lowest stomatal density) acclimated to eCO2 mostly via photosynthetic biochemistry. Tomato exhibited acclimation in both photosynthesis and gs kinetics. eCO2 acclimation in individual stomatal pore movement increased rates of pore aperture changes in chrysanthemum, but such acclimation responses resulted in no changes in gs responses. Although eCO2 acclimation occurred in all three crops, photosynthesis under fluctuating irradiance was hardly affected. Our study stresses the importance of quantifying eCO2 acclimatory responses at different integration levels to understand photosynthetic performance under future eCO2 environments. [ABSTRACT FROM AUTHOR]

AbstractThe availability of nutrients in the soil is a dynamic process that can fluctuate between states of deficiency and excess, causing significant stress on plants. In response to this stress, plants have evolved several physiological strategies to adapt and cope with these fluctuations. These strategies are aimed at improving the efficiency of nutrient uptake and utilization while minimizing the negative impact of nutrient stress. In this paper we explore the important roles and regulation of nutrient transporters in plant adaptation, including nitrogen, phosphorus, potassium, iron, and sulfur transporters. The paper discusses the mechanisms through which plants utilize these transporters to adapt to nutrient deficiencies and optimize nutrient uptake and utilization. The paper presents a comprehensive review of current understanding in these areas, highlighting their importance for plant growth and development, as well as their potential applications in agriculture. Additionally, the paper identifies research gaps and suggests future directions for research. In this review, we contribute to understanding the complex mechanisms that underpin plant adaptation and nutrition, and provides valuable insights for improving crop production and management. [ABSTRACT FROM AUTHOR]

Altitude is an important ecological factor affecting plant physiology and ecology, material metabolism and gene expression. Tuber color changes were observed in purple and red potatoes growing at four different elevations ranging from 1,800 ± 50 to 3,300 ± 50 m in the Tiger Leaping Gorge area of Yunnan Province. The results showed that the total phenol content, total flavone content, total anthocyanin content and biological yield of anthocyanin increased with increasing altitude until 2,800 ± 50 m, and the highest anthocyanin content were detected in the purple potato Huaxinyangyu and the red potato Jianchuanhong at the flowering stage and budding stage, respectively. Combined transcriptomic and metabolomic analyses revealed that the content and diversity of flavonoids are associated with genes expression via the promotion of propane metabolism to improve potato adaptation to different altitudes. These results provide a foundation for understanding the coloring mechanism and creating new potato germplasms with high resistance and good quality via genetic manipulation. [ABSTRACT FROM AUTHOR]

Premise: While many studies have measured the aboveground responses of plants to mycorrhizal fungi at a single time point, little is known about how plants respond belowground or across time to mycorrhizal symbiosis. By measuring belowground responses and growth over time in many plant species, we create a more complete picture of how mycorrhizal fungi benefit their hosts. Methods: We grew 26 prairie plant species with and without mycorrhizal fungi and measured 14 functional traits to assess above‐ and belowground tissue quality and quantity responses and changes in resource allocation. We used function‐valued trait (FVT) modeling to characterize changes in species growth rate when colonized. Results: While aboveground biomass responses were positive, the response of traits belowground were much more variable. Changes in aboveground biomass accounted for 60.8% of the variation in mycorrhizal responses, supporting the use of aboveground biomass response as the primary response trait. Responses belowground were not associated with aboveground responses and accounted for 18.3% of the variation. Growth responses over time were highly variable across species. Interestingly, none of the measured responses were phylogenetically conserved. Conclusions: Mycorrhizal fungi increase plant growth in most scenarios, but the effects of these fungi belowground and across time are more complicated. This study highlights how differences in plant allocation priorities might affect how they utilize the benefits from mycorrhizal fungi. Identifying and characterizing these differences is a key step to understanding the effects of mycorrhizal mutualisms on whole plant physiology. [ABSTRACT FROM AUTHOR]

Synthetic modulators of plant 14‐3‐3s are promising chemical tools both for understanding the 14‐3‐3‐related signaling pathways and controlling plant physiology. Herein, we describe a novel small‐molecule inhibitor for 14‐3‐3 proteins of Arabidopsis thaliana. The inhibitor was identified from unexpected products in a stock solution in dimethyl sulfoxide (DMSO) of an in‐house chemical library. Mass spectroscopy, mutant‐based analyses, fluorescence polarization assays, and thermal shift assays revealed that the inhibitor covalently binds to an allosteric site of 14‐3‐3 with isoform selectivity. Moreover, infiltration of the inhibitor to Arabidopsis leaves suppressed the stomatal aperture. The inhibitor should provide new insight into the design of potent and isoform‐selective 14‐3‐3 modulators. [ABSTRACT FROM AUTHOR]

Societal Impact Statement Summary Arbuscular mycorrhizal fungi (AMF) impact the relationships between plants, aphids (insects that feed on plant phloem), and their natural enemies (insects that prey on or parasitize aphids). The presence of AMF influences the growth and population of different aphid species and affects the development of aphid‐killing wasps and their attraction to plants. This research has been conducted also considering the insects' feeding strategy and their feeding specialization. This study provides novel perspectives on how these fungi shape interactions in the natural world, offering potential insights for the development of sustainable pest management strategies in agriculture. Arbuscular mycorrhizal fungi (AMF) are major root symbionts regulating plant physiology. Their presence affects the performance of aboveground insect herbivores in relation to their feeding strategy and their feeding specialization. For example, the effect of the arbuscular mycorrhizal (AM) symbiosis on chewing insects, positive for specialists and negative for generalists, has been previously demonstrated. Conversely, the impact of AMF on phloem‐suckers with relatively different levels of specialization remains unexplored. We tested the influence of the AM Funneliformis mosseae on the fitness of the specialist aphid Acyrthosiphon pisum and the generalist aphid Myzus persicae on Vicia faba plants. Further, we investigated the effects of AMF on the higher trophic level, the aphid parasitoids Aphidius ervi (specialist) and Aphidius colemani (generalist), by evaluating plant attractiveness and parasitoid fitness. To support the results of behavioral and biological bioassays we characterized the photosynthetic parameters, the volatilome and the transcriptome of tested plants. Mycorrhizal plants proved unsuitable for the generalist M. persicae but enhanced the fitness of the specialist A. pisum. The AM symbiosis had no effects on the behavioral response of A. colemani and enhanced the attraction and fitness of A. ervi. Volatilome and transcriptome profiling corroborated the results of bioassay highlighting a bottom‐up effect of the AMF across a plant–aphid–parasitoid system. [ABSTRACT FROM AUTHOR]

SUMMARY: Food security is threatened by climate change, with heat and drought being the main stresses affecting crop physiology and ecosystem services, such as plant–pollinator interactions. We hypothesize that tracking and ranking pollinators' preferences for flowers under environmental pressure could be used as a marker of plant quality for agricultural breeding to increase crop stress tolerance. Despite increasing relevance of flowers as the most stress sensitive organs, phenotyping platforms aim at identifying traits of resilience by assessing the plant physiological status through remote sensing‐assisted vegetative indexes, but find strong bottlenecks in quantifying flower traits and in accurate genotype‐to‐phenotype prediction. However, as the transport of photoassimilates from leaves (sources) to flowers (sinks) is reduced in low‐resilient plants, flowers are better indicators than leaves of plant well‐being. Indeed, the chemical composition and amount of pollen and nectar that flowers produce, which ultimately serve as food resources for pollinators, change in response to environmental cues. Therefore, pollinators' preferences could be used as a measure of functional source‐to‐sink relationships for breeding decisions. To achieve this challenging goal, we propose to develop a pollinator‐assisted phenotyping and selection platform for automated quantification of Genotype × Environment × Pollinator interactions through an insect geo‐positioning system. Pollinator‐assisted selection can be validated by metabolic, transcriptomic, and ionomic traits, and mapping of candidate genes, linking floral and leaf traits, pollinator preferences, plant resilience, and crop productivity. This radical new approach can change the current paradigm of plant phenotyping and find new paths for crop redomestication and breeding assisted by ecological decisions. Significance Statement: While climate change threatens food production through affecting plant physiology and pollinating ecosystem services, plant phenotyping platforms aim at identifying traits of resilience mostly based on vegetative indexes. However, since flowers are better indicators of the plant well‐being and provide food for pollinators, we propose to use the senses of animal pollinators and their preferences to assist in the identification of flower traits of resilience to abiotic stresses for plant breeding based on ecological decisions. [ABSTRACT FROM AUTHOR]

Summary: Climate change is simultaneously increasing carbon dioxide concentrations ([CO2]) and temperature. These factors could interact to influence plant physiology and performance. Alternatively, increased [CO2] may offset costs associated with elevated temperatures. Furthermore, the interaction between elevated temperature and [CO2] may differentially affect populations from along an elevational gradient and disrupt local adaptation.We conducted a multifactorial growth chamber experiment to examine the interactive effects of temperature and [CO2] on fitness and ecophysiology of diverse accessions of Boechera stricta (Brassicaceae) sourced from a broad elevational gradient in Colorado. We tested whether increased [CO2] would enhance photosynthesis across accessions, and whether warmer conditions would depress the fitness of high‐elevation accessions owing to steep reductions in temperature with increasing elevation in this system. Elevational clines in [CO2] are not as evident, making it challenging to predict how locally adapted ecotypes will respond to elevated [CO2].This experiment revealed that elevated [CO2] increased photosynthesis and intrinsic water use efficiency across all accessions. However, these instantaneous responses to treatments did not translate to changes in fitness. Instead, increased temperatures reduced the probability of reproduction for all accessions. Elevated [CO2] and increased temperatures interacted to shift the adaptive landscape, favoring lower elevation accessions for the probability of survival and fecundity.Our results suggest that elevated temperatures and [CO2] associated with climate change could have severe negative consequences, especially for high‐elevation populations. [ABSTRACT FROM AUTHOR]

Summary: Plasmodesmata are plasma membrane‐lined connections that join plant cells to their neighbours, establishing an intercellular cytoplasmic continuum through which molecules can travel between cells, tissues, and organs. As plasmodesmata connect almost all cells in plants, their molecular traffic carries information and resources across a range of scales, but dynamic control of plasmodesmal aperture can change the possible domains of molecular exchange under different conditions. Plasmodesmal aperture is controlled by specialised signalling cascades accommodated in spatially discrete membrane and cell wall domains. Thus, the composition of plasmodesmata defines their capacity for molecular trafficking. Further, their shape and density can likewise define trafficking capacity, with the cell walls between different cell types hosting different numbers and forms of plasmodesmata to drive molecular flux in physiologically important directions. The molecular traffic that travels through plasmodesmata ranges from small metabolites through to proteins, and possibly even larger mRNAs. Smaller molecules are transmitted between cells via passive mechanisms but how larger molecules are efficiently trafficked through plasmodesmata remains a key question in plasmodesmal biology. How plasmodesmata are formed, the shape they take, what they are made of, and what passes through them regulate molecular traffic through plants, underpinning a wide range of plant physiology. See also the Commentary on this article by Burch-Smith, 243: 5–6. [ABSTRACT FROM AUTHOR]

The content of selenium (Se) in most horticultural crops is low. To improve Se uptake in fruit trees, we investigated the impact of water extract derived from Nasturtium officinale R. Br. straw on the growth and Se uptake of peach seedlings under Se‐enriched soil by a pot experiment. The water extract of N. officinale straw exhibited notable effects on various growth parameters and Se accumulation in peach seedlings, with the most significant outcomes observed at a 200‐fold dilution. Specifically, the extract led to substantial enhancements in biomass, photosynthetic pigment content, antioxidant enzyme activity, and soluble protein content in peach seedlings. Remarkably, the 200‐fold dilution of N. officinale straw extract resulted in a 60.78% increase in root biomass and a 31.26% increase in shoot biomass when compared to the control. Moreover, the water extract augmented the levels of total Se, inorganic Se, and organic Se, along with the activities of Se metabolism‐related enzymes in peach seedlings. Among various tested dilutions, the 300‐fold and 400‐fold dilutions of N. officinale straw extract exhibited the highest total Se contents in roots and shoots, respectively, indicating increments of 97.26% and 44.08% over their respective controls. Additionally, correlation and gray relational analyses unveiled significant associations between peroxidase activity, soluble protein content, chlorophyll a content, chlorophyll a/b ratio, and the total shoot Se content. In conclusion, the water extract of N. officinale straw holds substantial potential for promoting the growth and Se uptake in peach seedlings, with the best concentration of 300‐fold dilution. [ABSTRACT FROM AUTHOR]

Selenium (Se) is an important trace element for human body, and the fruit Se source is one option for human Se supplementation. To increase grapevine uptake of Se, grape seedlings were transplanted in soils supplemented with sodium selenite, and the concentrations of 0, 1, 2, 4, and 6 g L−1 chitosan were sprayed on grapevine seedling leaves. Next, the effects of chitosan on grapevine Se uptake were studied. The chitosan‐based foliar application increased the biomass, photosynthetic pigment content, antioxidant enzyme activity, and soluble protein content of grapevine. Chitosan application also increased the total Se, inorganic Se, and organic Se contents in grapevine. However, while the root organic Se was increased, the shoot inorganic Se was decreased. Compared to the control, the concentrations of 1, 2, 4, and 6 g L−1 chitosan increased the shoot total Se content by 9.29%, 12.39%, 17.70%, and 14.16%, respectively. Chitosan application also increased the nitrogen (N), phosphorus (P), and potassium (K) contents in grapevine. Moreover, correlation, gray relational, principal component, and cluster analyses revealed that the root total Se, shoot total N, and root total K contents were the top three indicators closely associated with the shoot total Se content. Therefore, foliar‐based chitosan application on grape seedlings can promote the Se uptake in grapevine under sodium selenite supply, and 4 g L−1 is the best concentration. [ABSTRACT FROM AUTHOR]

The effects of exogenous strigolactone (using strigolactone analog GR24) on the cadmium (Cd) accumulation in Solanum nigrum var. humile were studied by a pot experiment. The Cd treatment (0.1 mg/L) inhibited the growth of S. nigrum var. humile, indicating that 0.1 mg/L produced the stress to S. nigrum var. humile. Spraying GR24 at 1 μmol/L did not change plant dry biomass, increased the photosynthetic pigment content and catalase activity, and decreased the peroxidase activity under Cd stress. By contrast, spraying GR24 at 2 μmol/L had no significant effects on these parameters. The superoxide dismutase activity was decreased by GR24 at 1 μmol/L, but increased by GR24 at 2 μmol/L. Nevertheless, both GR24 at 1 and 2 μmol/L increased the Cd contents, bioconcentration factors, and Cd extractions in various plant organs. Compared to Cd treatment, GR24 at 1 and 2 μmol/L increased the shoot Cd extraction by 20.0% and 14.5%, respectively. So, application of exogenous strigolactone could improve the phytoremediation capacity of S. nigrum var. humile. Correlation and grey relational analyses showed that the root Cd content, shoot Cd content, and root Cd extraction were the top three parameters closely related to the shoot Cd extraction. These findings suggest that exogenous strigolactone can effectively promote the Cd accumulation in S. nigrum var. humile, presenting a promising solution to enhance its phytoremediation capacity. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the biocontrol potential of Meyerozyma guilliermondii (CECT13190), an endophytic yeast, and its role in mitigating the adverse effects of abiotic and biotic stress in cucumber plants. The relevance of this study lies in addressing the threat of Fusarium wilt, a major fungal disease that impacts cucumber crop productivity, as well as the exacerbation of food scarcity caused by climate change-induced abiotic stress factors such as high temperatures and drought. The study was conducted in a greenhouse environment where Cucumis sativus seedlings were exposed to biotic (F. oxysporum inoculation) and abiotic stress conditions (heat and water deficit). The impact of M. guilliermondii on treated plants' physiology, growth, development, and flowering was assessed. The study confirmed the biocontrol activity of M. guilliermondii against F. oxysporum and highlighted its positive effects as a plant growth promoter. It enhanced overall plant health, activated natural defense mechanisms against F. oxysporum, and alleviated the detrimental impacts of abiotic stress. Notably, M. guilliermondii also induced early flowering in cucumber plants. This research underscores the potential of M. guilliermondii as a biocontrol agent for managing Fusarium wilt, enhancing stress tolerance, promoting early flowering, and offering promising prospects for sustainable crop production amidst fungal diseases and climate change-induced stressors. The findings emphasize the importance of utilizing M. guilliermondii to improve cucumber crop productivity and address food scarcity challenges. [ABSTRACT FROM AUTHOR]

Potassium (K) deficiency in corn is an emerging concern, especially when the crop is exposed to stress conditions. The insufficient replenishment of K in soil heightens the severity. A good K management requires adequate knowledge of its effect on plant growth and physiology. A sunlit growth chamber study was conducted under five levels of potassium concentrations, 100% (control; 193 ppm), 40%, 20%, 5%, and 0%, using modified Hoagland's nutrient solution applied at first leaf stage and continued until tasseling. The plant growth and development were monitored at different growth stages. Physiological parameters were measured at the tasseling stage. Significant differences (p < 0.05 to 0.001) in plant growth and physiological parameters were recorded in response to potassium rates. The 0% K treatment reduced the leaf K content and addition of leaf area day−1 by 85% and 8%, respectively, compared to the control. The rate of total biomass accumulation reduced to 5.4 g day−1 under 0% K compared to 7.7 g day−1 under the control. The root-to-shoot ratio increased to 0.33 at 5% K compared to 0.16 at the control treatment. The photosynthetic rate was reduced by 30% and 35% under 5% and 0% potassium concentrations, respectively, compared to the control. The 0% K deficiency decreased the stomatal conductance by 60% over control, lowering the internal CO2 level and transpiration. Linear and quadratic relationships were observed between leaf K content and electron transport rate (R2 = 0.98) and transpiration rate (R2 = 0.96), respectively. The functional relationships generated from this study will help improve corn models for field applications. [ABSTRACT FROM AUTHOR]

UV-A (315–400 nm) is a component of solar radiation, which impacts plant physiology. Consequently, the impact was investigated of UV-A supplementation on various aspects of kale cultivation in a plant factory with artificial lighting. Three UV-A intensity treatments (5, 10, or 15 W/m2) were applied to kale plants for 5 days before harvesting. The results revealed that 5 or 10 W/m2 UV-A supplementation provided significant advantages for kale growth. The fresh weight of the kale shoots increased by over 35–50% after UV-A exposure. In particular, the 10 W/m2 UV-A exposure significantly improved the photosynthetic rate, water-use efficiency, and quantum efficiency of photosystem II (Y(II)). In addition, the treatment with UV-A positively impacted changes in leaf spectral indices, resulting in decreases in the simple ratio index (SR), the normalized phaeophytinization index (NPQI), and the normalized difference red edge index (NDRE). Furthermore, the phytonutrients in kale (Vitamin C, soluble protein, and total phenolics) were enhanced using the 10 W/m2 UV-A treatment. One notable outcome was the consistent reduction in nitrate contents across all UV-A treatment intensities. Therefore, supplementing kale cultivation with UV-A radiation was a valuable strategy for enhancing kale yield and quality in plant factory production. [ABSTRACT FROM AUTHOR]

Introduction: The utilization of plant material for synthesizing nanoparticles effectively triggers physiological and biochemical responses in plants to combat abiotic stresses. Salt stress, particularly caused by NaCl, significantly affects plant morphology and physiology, leading to reduced crop yields. Understanding the mechanisms of salt tolerance is crucial for maintaining crop productivity. Methods: In this study, we examined the effects of 150 μM spinach-assisted gold nanoparticles (S-AuNPs) on various parameters related to seed germination, growth attributes, photosynthetic pigments, stomatal traits, ion concentrations, stress markers, antioxidants, metabolites, and nutritional contents of spinach plants irrigated with 50 mM NaCl. Results: Results showed that S-AuNPs enhanced chlorophyll levels, leading to improved light absorption, increased photosynthates production, higher sugar content, and stimulated plant growth under NaCl stress. Stomatal traits were improved, and partially closed stomata were reopened with S-AuNPs treatment, possibly due to K+/Na+ modulation, resulting in enhanced relative water content and stomatal conductance. ABA content decreased under S-AuNPs application, possibly due to K+ ion accumulation. S-AuNPs supplementation increased proline and flavonoid contents while reducing ROS accumulation and lipid peroxidation via activation of both non-enzymatic and enzymatic antioxidants. S-AuNPs also regulated the ionic ratio of K+/Na+, leading to decreased Na+ accumulation and increased levels of essential ions in spinach plants under NaCl irrigation. Discussion: Overall, these findings suggest that S-AuNPs significantly contribute to salt stress endurance in spinach plants by modulating various physiological attributes. [ABSTRACT FROM AUTHOR]

Irresponsible applications of chemical fertilizers and pesticides in agricultural production have caused significant environmental impacts a nd damage to human health. This study aimed to explore the effects of extracts from several Iranian medicinal plants on tomato growth under greenhouse conditions. Within a completely randomized design, the treatments included methanolic extracts of Taraxacum officinale L., Conocarpus erectus L., Allium jesdianum L., Rheum ribes L., Dorema aucheri L., and Juniperus sabina L. at three concentrations of 1000, 5000, and 8000 mg L-1. The measured variables were stem length (SL), internode distance (ID), branch number (BN), auxin content (AC), cytokinin content (CC), auxin/cytokinin ratio, total protein, total phenol content (TPC), total flavonoid content (TFC), and antioxidant potential (FRAP). Under greenhouse conditions, foliar spraying with Dorema aucheri plant extract (8000 mg L-1) significantly increased the stem length by 15% compared to the control. Rheum ribes extract (8000 mg L-1) increased internode distance (19%). However, the number of branches decreased by 34% in response to the plant extracts. Compared to the control, the amount of cytokinin decreased after spraying, whereas the auxin content showed a sinusoidal pattern of change. In response to all treatments, the auxin/cytokinin ratio increased, with the highest value observed in plants treated with Allium jesdianum extract (5000 mg L-1). According to the results, the plant extracts proved effective and assisted in tomato growth. Future research may aim to identify effective biological compounds in these extracts. [ABSTRACT FROM AUTHOR]

Abstract Chromium (Cr) is a toxic metal in soil–plant system, hence causing possible health risks prominently in the areas with forgoing industrial activities. Copper nanoparticles (Cu NPs) have been reported as an excellent adsorbent for pollutants. Therefore, this study investigates how copper nanoparticles enhance onion growth while decreasing chromium uptake in onion plants. Additionally, it examines the potential health risks of consuming onion plants with elevated chromium levels. The results demonstrated that the addition of CuNPs at 15 mg kg−1 significantly improved the plant height (48%), leaf length (37%), fresh weight of root (61%), root dry weight (70%), fresh weight of bulb (52%), bulb dry weight (59%), leaves fresh weight (52%) and dry weight of leaves (59%), leaf area (72%), number of onion leaves per plant (60%), Chl. a (42%), chl. b (36%), carotenoids (40%), total chlorophyll (40%), chlorophyll contents SPAD value (56%), relative water contents (35%), membrane stability index (16%), total sugars (25%), crude protein (21%), ascorbic acid (19%) and ash contents (64%) at 10 mg kg−1 Cr. Whereas, maximum decline of Cr by 46% in roots, 68% in leaves and 92% in bulb was found with application of 15 mg kg−1 of Cu NPs in onion plants under 10 mg kg−1 Cr toxicity. The health risk assessment parameters of onion plants showed minimum values 0.0028 for average daily intake (ADI), 0.001911 for Non-cancer risk (NCR), and 0.001433 for cancer risk (CR) in plants treated with Cu NPs at 15 mg kg−1 concentration grown in soil spiked with 10 mg kg−1 chromium. It is concluded that Cu NPs at 15 mg kg−1 concentration improved growth of plants in control as well as Cr contaminated soil. Therefore, use of Cu NPs at 15 mg kg−1 concentration is recommended for improving growth of plants under normal and metal contaminated soils.

Cold stress has an immediate impact on plant structure and function. A large number of free radicals cause oxidative stress in plants. Cold stress causes altered membrane permeability, lipid peroxidation, and DNA damage. It denatures enzymes and disrupts plant metabolism. Different methods are being investigated for acclimatizing plants subjected to cold stress. Nanobiotechnology and bacterial strains are growing agricultural strategies. Nanoparticles’ (NPs) unique qualities (small size, high mobility, biocompatibility, low cost, and increased reactivity) make them ideal candidates in agriculture. NP and bacterial applications maintain plastid structure and function, enhance antioxidant activities, secondary metabolites, and hormone expression, and reduce electrolyte leakage. They increase the number and content of proteins involved in oxidation–reduction reactions, hormone pathways, stress signaling, and reactive oxygen species detoxification under cold stress conditions. Chitosan, zinc oxide, and titanium dioxide NPs can help plants with cold stress. Meanwhile, bacterial strains in the genus Bacillus and Pseudomonas have been tested for cold tolerance. These strategies also upregulate antifreeze proteins, which are essential for the storage of plant products. Nano-bio-fertilizers should be prepared for the sustainable development of plants under low temperatures.

Vladimir Aleksandrovich Koshkin was a prominent representative of the school of plant physiologists at the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR). He introduced his ideas on the mechanisms of photosynthesis intensity as well as the distribution of photoperiod sensitivity and the rate of development among plant species diversity. He was the first to examine in detail and disclose the relationship between the carbon dioxide compensation point and leaf temperature in C3 and C4 plants. According to Dr. Koshkin, there was no change in the sign of the photoperiodic reaction in the generic evolution of Triticum L. and Aegilops L., while the spring forms of bread and durum wheat widespread in the equatorial zone demonstrated weak photoperiod sensitivity. In his work with the resource departments of VIR, Dr. Koshkin was interested in plant breeding problems in the context of developing earlier-ripening cereal cultivars with a certain reaction to the photoperiod. His joint research projects with a number of breeding centers in Russia on this problem proved effective. He participated in collecting missions in Latin American countries (Cuba, Mexico, Colombia, and Brazil) and was awarded a Timiryazev Gold Medal. Dr. Koshkin was the author of 163 scientific publications and had about 20 certificates of authorship and patents for inventions, crop cultivars and lines. Dr. Vladimir Koshkin was quick to perceive the essence of any problem and used adequate modern methods to set up and analyze high-precision experiments.

Abstract Background Biochar, a carbon-rich source and natural growth stimulant, is usually produced by the pyrolysis of agricultural biomass. It is widely used to enhance plant growth, enzyme activity, and crop productivity. However, there are no conclusive studies on how different levels of biochar application influence these systems. Methods and results The present study elucidated the dose-dependent effects of biochar application on the physiological performance, enzyme activity, and dry matter accumulation of tobacco plants via field experiments. In addition, transcriptome analysis was performed on 60-day-old (early growth stage) and 100-day-old (late growth stage) tobacco leaves to determine the changes in transcript levels at the molecular level under various biochar application levels (0, 600, and 1800 kg/ha). The results demonstrated that optimum biochar application enhances plant growth, regulates enzymatic activity, and promotes biomass accumulation in tobacco plants, while higher biochar doses had adverse effects. Furthermore, transcriptome analysis revealed a total of 6561 differentially expressed genes (DEGs) that were up- or down-regulated in the groupwise comparison under different treatments. KEGG pathways analysis demonstrated that carbon fixation in photosynthetic organisms (ko00710), photosynthesis (ko00195), and starch and sucrose metabolism (ko00500) pathways were significantly up-regulated under the optimal biochar dosage (600 kg/ha) and down-regulated under the higher biochar dosage (1800 kg/ha). Conclusion Collectively, these results indicate that biochar application at an optimal rate (600 kg/ha) could positively affect photosynthesis and carbon fixation, which in turn increased the synthesis and accumulation of sucrose and starch, thus promoting the growth and dry matter accumulation of tobacco plants. However, a higher biochar dosage (1800 kg/ha) disturbs the crucial source-sink balance of organic compounds and inhibits the growth of tobacco plants.