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In the present study, an indoor potting experiment was conducted to study the effects of enhanced UV-B radiation and Magnaporthe oryzae on the growth, stomatal structure, photosynthesis, and endogenous hormone contents of a traditional rice cultivar Baijiaolaojing in the Yuanyang terraces of Yunnan Province. In addition, the relationships between these parameters and disease indices were analyzed. We aimed to clarify the response of the photosynthetic physiology of rice under the combined stress of UV-B radiation and M. oryzae. Compared with the M. oryzae infection treatment, all the treatments, including M. oryzae infection before (MBR), simultaneously with (MSR), and after (MAR) UV-B radiation significantly increased the rice height and biomass by 4%–11% and 30%–111%, respectively, and the stomatal structure and carotenoids content of leaves, while decreasing the contents of chlorophyll a and b, by 21%–41% and 63%–73%, respectively. Both the MSR and MBR treatments significantly increased the photosynthetic rate and transpiration rate of rice leaves. The MAR treatment weakened chlorophyll fluorescence parameters, including the actual photosystem II (PS II) photochemical efficiency, electron transport rate, photochemical quenching, and nonphotochemical quenching by 40%, 39%, 43%, and 24%, respectively. Moreover, the treatments of MAR, MSR, and MBR decreased the phytohormones content and the M. oryzae disease index by 27%–62% in rice leaves. Thus, the enhanced UV-B radiation contributed to suppressing the M. oryzae infection and alleviating its damage to the photosynthesis of rice leaves. This study is valuable for the control of rice blast fungus and offers important insights into plant pathology. [ABSTRACT FROM AUTHOR]

The mutualistic plant rhizobacteria which improve plant development and productivity are known as plant growth-promoting rhizobacteria (PGPR). It is more significant due to their ability to help the plants in different ways. The main physiological responses, such as malondialdehyde, membrane stability index, relative leaf water content, photosynthetic leaf gas exchange, chlorophyll fluorescence efficiency of photosystem-II, and photosynthetic pigments are observed in plants during unfavorable environmental conditions. Plant rhizobacteria are one of the more crucial chemical messengers that mediate plant development in response to stressed conditions. The interaction of plant rhizobacteria with essential plant nutrition can enhance the agricultural sustainability of various plant genotypes or cultivars. Rhizobacterial inoculated plants induce biochemical variations resulting in increased stress resistance efficiency, defined as induced systemic resistance. Omic strategies revealed plant rhizobacteria inoculation caused the upregulation of stress-responsive genes--numerous recent approaches have been developed to protect plants from unfavorable environmental threats. The plant microbes and compounds they secrete constitute valuable biostimulants and play significant roles in regulating plant stress mechanisms. The present review summarized the recent developments in the functional characteristics and action mechanisms of plant rhizobacteria in sustaining the development and production of plants under unfavorable environmental conditions, with special attention on plant rhizobacteria-mediated physiological and molecular responses associated with stress-induced responses. [ABSTRACT FROM AUTHOR]

Plant temperature acclimation is closely related to maintaining a positive carbon gain under future climate change. However, no systematic summary of the field has been conducted. Based on this, we analyzed data on plant temperature acclimation from the Web of Science Core Collection database using bibliometric software R, RStudio and VOSviewer. Our study demonstrated that a stabilized upward trajectory was noted in publications (298 papers) from 1986 to 2011, followed by a swift growth (373 papers) from 2012 to 2022. The most impactful journals were Plant Cell and Environment, boasting the greatest count of worldwide citations and articles, the highest H-index and G-index, followed by Global Change Biology and New Phytologist, and Frontiers in Plant Science which had the highest M-index. The USA and China were identified as the most influential countries, while Atkin was the most influential author, and the Chinese Academy of Sciences was the most influential research institution. The most cited articles were published in the Annual Review of Plant Biology in 1999. “Cold acclimation” was the most prominent keyword. Future plant temperature acclimation research is expected to focus on thermal acclimation and photosynthesis, which have important significance for future agricultural production, forestry carbon sequestration, and global food security. In general, this study provides a systematic insight of the advancement, trend, and future of plant temperature acclimation research, enhancing the comprehension of how plants will deal with forthcoming climate change. [ABSTRACT FROM AUTHOR]

Background: Phosphorus (P) is an essential nutrient for plant growth, taking part in primary cellular metabolic processes as a structural component of key biomolecules. Soil processes as adsorption, precipitation, and coprecipitation can affect P bioavailability, leading to limited plant growth and excessive use of P fertilizers, with adverse impacts on the environment and progressive depletion of P reserves. To cope with P stress, plants undergo several growth, development, and metabolic adjustments, aimed at increasing P-acquisition and -utilization efficiency. Recently, strigolactones (SLs) have emerged as newly defined hormones that mediate multiple levels of morphological, physiological and biochemical changes in plants as part of the P acclimation strategies to optimize growth. Therefore, understanding the soil processes affecting P availability and P acquisition strategies by plants can contribute to improved agronomical practices, resources optimization and environmental protection, and the development of plants with high P use efficiency for enhanced agricultural productivity. Scope: In this review, we discuss the range of abiotic processes that control P retention in soil and how different concentrations or degrees of P bioavailability can trigger various responses in plants, while critically highlighting the inconsistent conditions under which experiments evaluating aspects of P nutrition in plants have been conducted. We also present recent advances in elucidating the role of SLs in the complex P signalling pathway, with a special focus on what has been discovered so far in the model plant tomato (Solanum lycopersicum L.). [ABSTRACT FROM AUTHOR]

The mutualistic plant rhizobacteria which improve plant development and productivity are known as plant growth-promoting rhizobacteria (PGPR). It is more significant due to their ability to help the plants in different ways. The main physiological responses, such as malondialdehyde, membrane stability index, relative leaf water content, photosynthetic leaf gas exchange, chlorophyll fluorescence efficiency of photosystem-II, and photosynthetic pigments are observed in plants during unfavorable environmental conditions. Plant rhizobacteria are one of the more crucial chemical messengers that mediate plant development in response to stressed conditions. The interaction of plant rhizobacteria with essential plant nutrition can enhance the agricultural sustainability of various plant genotypes or cultivars. Rhizobacterial inoculated plants induce biochemical variations resulting in increased stress resistance efficiency, defined as induced systemic resistance. Omic strategies revealed plant rhizobacteria inoculation caused the upregulation of stress-responsive genes—numerous recent approaches have been developed to protect plants from unfavorable environmental threats. The plant microbes and compounds they secrete constitute valuable biostimulants and play significant roles in regulating plant stress mechanisms. The present review summarized the recent developments in the functional characteristics and action mechanisms of plant rhizobacteria in sustaining the development and production of plants under unfavorable environmental conditions, with special attention on plant rhizobacteria-mediated physiological and molecular responses associated with stress-induced responses.

Purpose Soybean is critical in the global food scenario, and increased grain productivity and sustainability are always sought. This study evaluates the agronomic performance of soybeans with biofertilizer (BF) applications in different soybean phenological stages.Method Experiments were performed in two regions and designed in randomized blocks using a 2×4 factorial scheme (two cultivars and four BF managements). Representative plants from each parcel were used. Plant biometric variables were assessed on plants at the full bloom stage. At the beginning of grain filling, the leaf and seed biochemical components were measured. Quantitative yield components were measured at harvest.Results In both areas, the BF did not affect the soybean leaf area index, leaf dry biomass, and branch dry biomass. The BF application improved the total sugars, starch, and reducing sugars in area 1. In area 2, the chlorophyll was similar among the BF managements. Soybean cultivars and BF did not affect seed protein content in area 1. In area 2, the BF application presented a similar or greater soybean yield compared to control (no BF). The divergences observed between areas may be related to interactions between the soil-climatic conditions and the soybean cultivars.Conclusion Choosing a more appropriate soybean cultivar is fundamental to obtaining higher yields. Nutritional management with leaf-applied BF is an alternative to increase soybean field performance. However, it is still necessary to consider the interactions of the BF with the crop genetics chosen for the region of cultivation and the best dose and time of application.

Nitric oxide (NO) is a small, diatomic, gaseous, free radicle, lipophilic, diffusible, and highly reactive molecule with unique properties that make it a crucial signaling molecule with important physiological, biochemical, and molecular implications for plants under normal and stressful conditions. NO regulates plant growth and developmental processes, such as seed germination, root growth, shoot development, and flowering. It is also a signaling molecule in various plant growth processes, such as cell elongation, differentiation, and proliferation. NO also regulates the expression of genes encoding hormones and signaling molecules associated with plant development. Abiotic stresses induce NO production in plants, which can regulate various biological processes, such as stomatal closure, antioxidant defense, ion homeostasis, and the induction of stress-responsive genes. Moreover, NO can activate plant defense response mechanisms, such as the production of pathogenesis-related proteins, phytohormones, and metabolites against biotic and oxidative stressors. NO can also directly inhibit pathogen growth by damaging their DNA and proteins. Overall, NO exhibits diverse regulatory roles in plant growth, development, and defense responses through complex molecular mechanisms that still require further studies. Understanding NO's role in plant biology is essential for developing strategies for improved plant growth and stress tolerance in agriculture and environmental management. [ABSTRACT FROM AUTHOR]

Purpose Soybean is critical in the global food scenario. The increase of grain productivity and sustainability are always wanted. This study evaluates the agronomic performance of soybeans with biofertilizer (BF) applications in different soybean phenological stages. Method Experiments were performed in two regions and designed in randomized blocks using a 2×4 factorial scheme (two cultivars and four BF managements). Representative plants from each parcel were used. Plant biometric variables were assessed on plants at the full bloom stage. At the beginning of grain filling, the leaf and seed biochemical components were measured. Quantitative yield components were measured at harvest. Results In both areas, the BF did not affect the soybean leaf area index, leaf dry biomass, and branch dry biomass. The BF application improved the total sugars, starch, and reducing sugars in area 1. In area 2, the chlorophyll was similar among the BF managements. Soybean cultivars and BF did not affect seed protein content in area 1. In area 2, the BF application presented a similar or greater soybean yield compared to control (no BF). The divergences observed between areas may be related to interactions between the soil-climatic conditions and the soybean cultivars. Conclusion Choosing a more appropriate soybean cultivar is fundamental to obtaining higher yields. Nutritional management with leaf-applied BF is an alternative to increase soybean field performance. However, it is still necessary to consider the interactions of the BF with the crop genetics chosen for the region of cultivation and the best dose and time of application. [ABSTRACT FROM AUTHOR]

Radiation is widespread in nature, including ultraviolet radiation from the sun, cosmic radiation and radiation emitted by natural radionuclides. Over the years, the increasing industrialization of human beings has brought about more radiation, such as enhanced UV-B radiation due to ground ozone decay, and the emission and contamination of nuclear waste due to the increasing nuclear power plants and radioactive material industry. With additional radiation reaching plants, both negative effects including damage to cell membranes, reduction of photosynthetic rate and premature aging and benefits such as growth promotion and stress resistance enhancement have been observed. ROS (Reactive oxygen species) are reactive oxidants in plant cells, including hydrogen peroxide (H2O2), superoxide anions (O2•−) and hydroxide anion radicals (·OH), which may stimulate the antioxidant system of plants and act as signaling molecules to regulate downstream reactions. A number of studies have observed the change of ROS in plant cells under radiation, and new technology such as RNA-seq has molecularly revealed the regulation of radiative biological effects by ROS. This review summarized recent progress on the role of ROS in plant response to radiations including UV, ion beam and plasma, and may help to reveal the mechanisms of plant responses to radiation. [ABSTRACT FROM AUTHOR]

Global climate change is expected to further increase the frequency and severity of extreme events, such as high temperature/heat waves as well as drought in the future. Thus, how plant responds to high temperature and drought has become a key research topic. In this study, we extracted data from Web of Science Core Collections database, and synthesized plant responses to high temperature and drought based on bibliometric methods using software of R and VOSviewer. The results showed that a stabilized increasing trend of the publications (1199 papers) was found during the period of 2008 to 2014, and then showed a rapid increase (2583 papers) from year 2015 to 2021. Secondly, the top five dominant research fields of plant responses to high temperature and drought were Plant Science, Agroforestry Science, Environmental Science, Biochemistry, and Molecular Biology, respectively. The largest amount of published article has been found in the Frontiers in Plant Science journal, which has the highest global total citations and H-index. We also found that the journal of Plant Physiology has the highest local citations. From the most cited papers and references, the most important research focus was the improvement of crop yield and vegetation stress resistance. Furthermore, “drought” has been the most prominent keyword over the last 14 years, and more attention has been paid to “climate change” over the last 5 years. Under future climate change, how to regulate growth and development of food crops subjected to high temperature and drought stress may become a hotspot, and increasing research is critical to provide more insights into plant responses to high temperature and drought by linking plant above-below ground components. To summarize, this research will contribute to a comprehensive understanding of the past, present, and future research on plant responses to high temperature and drought. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) is a small, diatomic, gaseous, free radicle, lipophilic, diffusible, and highly reactive molecule with unique properties that make it a crucial signaling molecule with important physiological, biochemical, and molecular implications for plants under normal and stressful conditions. NO regulates plant growth and developmental processes, such as seed germination, root growth, shoot development, and flowering. It is also a signaling molecule in various plant growth processes, such as cell elongation, differentiation, and proliferation. NO also regulates the expression of genes encoding hormones and signaling molecules associated with plant development. Abiotic stresses induce NO production in plants, which can regulate various biological processes, such as stomatal closure, antioxidant defense, ion homeostasis, and the induction of stress-responsive genes. Moreover, NO can activate plant defense response mechanisms, such as the production of pathogenesis-related proteins, phytohormones, and metabolites against biotic and oxidative stressors. NO can also directly inhibit pathogen growth by damaging their DNA and proteins. Overall, NO exhibits diverse regulatory roles in plant growth, development, and defense responses through complex molecular mechanisms that still require further studies. Understanding NO’s role in plant biology is essential for developing strategies for improved plant growth and stress tolerance in agriculture and environmental management.

Radiation is widespread in nature, including ultraviolet radiation from the sun, cosmic radiation and radiation emitted by natural radionuclides. Over the years, the increasing industrialization of human beings has brought about more radiation, such as enhanced UV-B radiation due to ground ozone decay, and the emission and contamination of nuclear waste due to the increasing nuclear power plants and radioactive material industry. With additional radiation reaching plants, both negative effects including damage to cell membranes, reduction of photosynthetic rate and premature aging and benefits such as growth promotion and stress resistance enhancement have been observed. ROS (Reactive oxygen species) are reactive oxidants in plant cells, including hydrogen peroxide (H2O2), superoxide anions (O2•−) and hydroxide anion radicals (·OH), which may stimulate the antioxidant system of plants and act as signaling molecules to regulate downstream reactions. A number of studies have observed the change of ROS in plant cells under radiation, and new technology such as RNA-seq has molecularly revealed the regulation of radiative biological effects by ROS. This review summarized recent progress on the role of ROS in plant response to radiations including UV, ion beam and plasma, and may help to reveal the mechanisms of plant responses to radiation.

Increasing population and subsequent food requirement puts a lot of onus on agriculture worldwide. However, agricultural output is constantly influenced by several factors such as small land holdings, lack of proper mechanization, and occurrence of several abiotic and biotic stresses. Drought stress is one such abiotic stress which causes major setbacks to agricultural productivity every year. Water scarcity due to decline in rainfall and increased frequency of dry spells give rise to drought conditions. Often drought is accompanied by other detrimental effects like salinity, heat and attack of pathogens. In response plants undergo several physiological and morphological modifications like reduced transpiration and photosynthesis rate, osmotic adjustments, repressed root and shoot growth, overproduction of reactive oxygen species (ROS), modified stress signalling pathways, and senescence. These modifications can cause permanent injury to the plant and hence there is a need to develop mitigation strategies. Employment of nanoparticles, film farming, use of drought resistant plant varieties, super-absorbent hydrogels, and biochar are some techniques used to ameliorate drought stress. Though, most of these practices are labour-intensive and expensive with limited benefits. Application of plant-growth-promoting rhizobacteria (PGPR), however, is proving to be a preferential strategy that encompasses many direct and indirect benefits. PGPRs impart induced systemic tolerance (IST) to plants towards drought stress through a variety of mechanisms like improvement of antioxidant system, production of ACC-deaminase and phytohormones, nitrogen fixation, phosphate solubilization, siderophore and exopolysaccharides production, enhanced root and shoot system, amplified photosynthesis rates and carotenoid production. The commercial applicability of PGPRs as biostimulants will still be dependent on the selection and performance of robust strains in various environmental conditions.

Phenotypic plasticity is one mechanism that allows organisms to adapt to changing environmental conditions, and is especially important for plants since they are generally immobile. Recent anthropogenic disturbances such as oil spills have expanded the types of stressors that plants must cope with, and more work is needed to understand the extent to which plants can adapt. This study examined the physiological and anatomical responses of Ipomoea pes-caprae to crude oil, and determined its plasticity in response to crude oil. Four concentrations of crude oil (1%, 2%, 3%, and 4% v/w) were applied to experimental plants and then compared with control plants over the next 120 days. Crude oil meaningfully impacted 4 out of 5 physiological characters (survival time, leaf length, leaf width, and chlorophyll content) and 4 out of 19 anatomical characters (leaf blade thickness, leaf spongy layer height, leaf adaxial cutin thickness, and leaf abaxial cutin thickness). These results demonstrate that I. pes-caprae exhibits low anatomical plasticity in response to crude oil, resulting in reduced survival and physiological performance. Our findings highlight the importance of understanding how anthropogenic actions affect relatively immobile plants, which are not always able to cope with such stressors. [ABSTRACT FROM AUTHOR]

Strigolactones (SLs) are important ex‐planta signalling molecules in the rhizosphere, promoting the association with beneficial microorganisms, but also affecting plant interactions with harmful organisms. They are also plant hormones in‐planta, acting as modulators of plant responses under nutrient‐deficient conditions, mainly phosphate (Pi) starvation. In the present work, we investigate the potential role of SLs as regulators of early Pi starvation signalling in plants. A short‐term pulse of the synthetic SL analogue 2′‐epi‐GR24 promoted SL accumulation and the expression of Pi starvation markers in tomato and wheat under Pi deprivation. 2′‐epi‐GR24 application also increased SL production and the expression of Pi starvation markers under normal Pi conditions, being its effect dependent on the endogenous SL levels. Remarkably, 2′‐epi‐GR24 also impacted the root metabolic profile under these conditions, promoting the levels of metabolites associated to plant responses to Pi limitation, thus partially mimicking the pattern observed under Pi deprivation. The results suggest an endogenous role for SLs as Pi starvation signals. In agreement with this idea, SL‐deficient plants were less sensitive to this stress. Based on the results, we propose that SLs may act as early modulators of plant responses to P starvation. The current work provides evidences supporting that the phytohormone strigolactones are early modulators of plant responses to low Pi availability and that they impact metabolic profiles in the roots. This knowledge may help to develop new strategies to optimize plant Pi acquisition efficiency and use. [ABSTRACT FROM AUTHOR]

The functional root traits of Pyrus pyraster (L.) Burgsd. and Sorbus domestica L. during early growth stages were evaluated. The aim of the study was to identify the functional traits of root systems that determine the adaptability of these woody species to drought conditions. The experiment was carried out under the controlled environment of a growth chamber. The root systems were analyzed using WinRhizo software. Several functional root traits were identified, including specific root length, root surface area, root length, root volume, root-to-shoot mass ratio (R:S), fine root (ϕ ˂ 2 mm) volume, coarse root (ϕ > 2 mm) volume, and fine-to-coarse root volume ratio (F/C). In drought, P. pyraster maintained the absorptive root surface unchanged, when increased the volume of the fine root fraction. The different strategy of adaptation to drought has been confirmed for S. domestica, which accumulated more dry mass in the root system in comparison to aboveground organs (significant increase of R:S ratio). The functional root traits analyzed here were species-dependent. The key functional traits that indicate the responses of studied tree taxa to drought conditions include root thickening, F/C, and R:S. Increased values of these parameters indicate the investment of the plant towards root extension. A higher proportion of fine roots increases the absorbing surface of the root system, thereby promoting water uptake from the soil. [ABSTRACT FROM AUTHOR]

Expeditious industrialization and anthropogenic activities have resulted in large amounts of heavy metals (HMs) being released into the environment. These HMs affect crop yields and directly threaten global food security. Therefore, significant efforts have been made to control the toxic effects of HMs on crops. When HMs are taken up by plants, various mechanisms are stimulated to alleviate HM stress, including the biosynthesis and transport of auxin in the plant. Interestingly, researchers have noted the significant potential of auxin in mediating resistance to HM stress, primarily by reducing uptake of metals, promoting chelation and sequestration in plant tissues, and mitigating oxidative damage. Both exogenous administration of auxin and manipulation of intrinsic auxin status are effective strategies to protect plants from the negative consequences of HMs stress. Regulation of genes and transcription factors related to auxin homeostasis has been shown to be related to varying degrees to the type and concentration of HMs. Therefore, to derive the maximum benefit from auxin-mediated mechanisms to attenuate HM toxicities, it is essential to gain a comprehensive understanding of signaling pathways involved in regulatory actions. This review primarily emphases on the auxin-mediated mechanisms participating in the injurious effects of HMs in plants. Thus, it will pave the way to understanding the mechanism of auxin homeostasis in regulating HM tolerance in plants and become a tool for developing sustainable strategies for agricultural growth in the future. • Auxin homeostasis orchestrates plant tolerance to HMs through different mechanisms. • HM stress alters auxin level through regulating signaling and biosynthesis network. • Auxin mediated phytohormonal tuning involved in defense against HM stress. [ABSTRACT FROM AUTHOR]

Abiotic stresses are major constraints to crop production and food security worldwide, the increasing trend and projection under climate change pose further challenge and warrants close attention of researchers and policy makers. Heat and drought are judged as most common stresses having adverse impact on growth and productivity of the crops. Understanding of the physiological, biochemical, and ecological responses of these stresses is prerequisite to develop management practices. The plant responses to these stresses can be categorized into morphological, physiological, and biochemical responses quantified to assess their impact. Though plants have capability to modify their growth pattern and physiological process to cope with heat and drought stresses but it costs dearly in terms of overall performance and yield, therefore it is a must to understand plant response to various stresses in order to develop suitable adaptation strategies. This review focuses on the plant responses towards heat and drought stresses pointing on the commonalities and differences. Due to physical damages, physiological disruptions, and biochemical changes under limited water supply and elevated temperatures there is negative impact on crop growth and yields. Both conventional and modern approaches are desired to deal with heat and drought stresses. A holistic approach including short term strategy comprising management practices promoting in-situ moisture conservation, water harvesting, micro environment modification etc, and long term strategies including developing heat and drought tolerant varieties, developing irrigation infrastructure, permanent change in land configuration, etc are required. The recent government. initiative like PMKSY aiming irrigation to each field (Har Khet Ko Pani) through water harvesting, conveyance, drip irrigation in the back drop of time bound target of doubling farmers income will be a big boost to cope heat and drought stress and to induce climatic resilience.

The effects of climate warming on boreal wetland plant structure and carbon (C) sequestration on local scale may be overestimated. An in situ passive warming experiment manipulated by open-top chambers and artificial nitrogen (N) addition was deployed in a lacustrine wetland of Xingkai Lake for 3 consecutive years. The annual changes and allocations of the aboveground biomass of Glyceria spiculosa , and decomposition dynamics of the total litter and cotton strips as standard references were observed. Results showed that the aboveground biomass was significantly affected by warming and increased from 99.43 ± 10.59 g m−2 (ambient) to 112.02 ± 8.08 g m−2 (ca. +1 °C) and 117.21 ± 9.92 g m−2 (ca. +2 °C). N addition had a more positive effect on the annual aboveground biomass accumulations than warming, for the relative importance weights of N addition were 2.60 and 1.49 times greater than warming in 2011 and 2013 respectively. Their main effects on the allocations had significant interannual variations, and their interaction effects were dependent on organ and year. The decomposition constant (k-value) of the litter and cotton strips were 0.747 yr−1 and 2.057 yr−1, respectively. Compared to warming and N addition, the internal quality characterized by Lignocellulose index and soil organisms reflected by litterbag size played overwhelming role in decomposition dynamics, with 2 orders greater of relative importance weights in 2011 and 2012. Our results highlight the importance of interannual variation for differentiating the contributions of external and internal factors to boreal wetland plant biomass accumulation and decomposition. Given the asymmetric responses of accumulation and decomposition, the C storage in the litter would increase in long term. Unlabelled Image • In situ warming and N addition were set to test biomass and litter dynamics. • N addition had a more positive effect on biomass accumulations than warming. • N addition and warming were too small to affect litter decomposition dynamics. • Their effects were time-dependent with interannual variations. • C storage in litter compartment would increase for asymmetric responses. [ABSTRACT FROM AUTHOR]

Highlights from the article: This Research Topic provides an update on recent advances in the plant molecular and physiological mechanisms associated with phytophagous mite/thrips-plant interactions, and provides an overview of different approaches for improving crop resistance sustainably, either through repellence, feeding disruption or prevention of feeding damage. It is expected that KTI impact mite gut cysteine-proteases involved in the hydrolysis of dietary proteins and can thus be used as a potential tool to engineer plant resistance/tolerance to I T. urticae i . Schausberger discussed the abundance and diversity of bacteria associated with spider mites and thrips, and argued that these can have a profound impact on herbivore-induced plant defense responses. Plant-herbivore interactions: a case of an extreme generalist, the Two-Spotted Spider Mite Tetranychus urticae.

Heavy metals such as Fe, Mn, Cu, Ni, Co, Cd, Zn, Hg and arsenic are for long being accumulated in soils through industrial waste and sewage disposal. Although some of these metals are essential micronutrients responsible for many regular processes in plants, their excess, however, can have detrimental effects and can directly influence the plant growth, metabolism, physiology and senescence. Plants have different mechanisms to fight stress, and they are responsible to maintain homeostasis of essential metals required by plants. These mechanisms also focus on prevention of plants exposure to heavy metals present in the soil or providing tolerance to the plant by detoxifying the metals. Other mechanisms are specific and are initiated when the respective stress is encountered. The first line of defense provided by a plant is to reduce the uptake of metals when stimulated with toxicity of heavy metals and includes the help offered by cellular and root exudates that restricts metals from entering the cell. Many plants have exclusive mechanisms for individual metal ions and are involved in sequestering these ions in compartments avoiding their exposure to sensitive components of the cells. As a second line of defense, other mechanisms for detoxification of these metals are introduced that chelates, transports, sequesters and detoxifies these metal ions in the plant's vacuole. During the time of metal toxicity, oxidative stress is pronounced in the cells and production of stress-related proteins and hormones, antioxidants, signaling molecules including heat-shock proteins synthesis is initiated. [ABSTRACT FROM AUTHOR]

Plants face a combination of different abiotic stresses under field conditions which are lethal to plant growth and production. Simultaneous occurrence of chilling and drought stresses in plants due to the drastic and rapid global climate changes, can alter the morphological, physiological and molecular responses. Both these stresses adversely affect the plant growth and yields due to physical damages, physiological and biochemical disruptions, and molecular changes. In general, the co-occurrence of chilling and drought combination is even worse for crop production rather than an individual stress condition. Plants attain various common and different physiological and molecular protective approaches for tolerance under chilling and drought stresses. Nevertheless, plant responses to a combination of chilling and drought stresses are unique from those to individual stress. In the present review, we summarized the recent evidence on plant responses to chilling and drought stresses on shared as well as unique basis and tried to find a common thread potentially underlying these responses. We addressed the possible cross talk between plant responses to these stresses and discussed the potential management strategies for regulating the mechanisms of plant tolerance to drought and/or chilling stresses. To date, various novel approaches have been tested in minimizing the negative effects of combine stresses. Despite of the main improvements there is still a big room for improvement in combination of drought and chilling tolerance. Thus, future researches particularly using biotechnological and molecular approaches should be carried out to develop genetically engineered plants with enhanced tolerance against these stress factors.

Plants face a combination of different abiotic stresses under field conditions which are lethal to plant growth and production. Simultaneous occurrence of chilling and drought stresses in plants due to the drastic and rapid global climate changes, can alter the morphological, physiological and molecular responses. Both these stresses adversely affect the plant growth and yields due to physical damages, physiological and biochemical disruptions, and molecular changes. In general, the co-occurrence of chilling and drought combination is even worse for crop production rather than an individual stress condition. Plants attain various common and different physiological and molecular protective approaches for tolerance under chilling and drought stresses. Nevertheless, plant responses to a combination of chilling and drought stresses are unique from those to individual stress. In the present review, we summarized the recent evidence on plant responses to chilling and drought stresses on shared as well as unique basis and tried to find a common thread potentially underlying these responses. We addressed the possible cross talk between plant responses to these stresses and discussed the potential management strategies for regulating the mechanisms of plant tolerance to drought and/or chilling stresses. To date, various novel approaches have been tested in minimizing the negative effects of combine stresses. Despite of the main improvements there is still a big room for improvement in combination of drought and chilling tolerance. Thus, future researches particularly using biotechnological and molecular approaches should be carried out to develop genetically engineered plants with enhanced tolerance against these stress factors. [ABSTRACT FROM AUTHOR]

The present experiment was aimed at determining the influence of the grape erineum strain of Colomerus vitis (GEM) (Acari: Eriophyidae) on responses of local grapevine cultivars. GEM was applied at five density levels to each of five cultivars, i.e. Shahani, Sahebi Uroomie, Khalili Bovanat, Rishbaba and Sezdang Ghalat (listed from early to late grape ripening). The experiment was performed in a full factorial design (12 replicates each) and effects of the mite on the relative content of leaf chlorophyll, internode and cane length, leaf area and weight, number and size of the erinea, and percentage of leaves with erinea were investigated. Also mite density on leaves and in buds was assessed. Data were analyzed with a two-way ANOVA followed by Tukey’s test to separate means among treatment levels and cultivars. The relative content of chlorophyll (expressed in Spad units) in infested leaves was reduced along with an increase in mite density and it was shown to be highly significant at the two higher mite density levels for Khalili Bovanat, Rishbaba and Sezdang Ghalat; Shahani and Sahebi Uroomie leaves appeared to be less affected by mite infestation. The highest mite density treatment displayed a strong correlation with weight (positive correlation) and size (negative correlation) of the leaves of four cultivars; leaves of Sahebi Uroomie appeared to be less affected. The reduced internode length was weak in infested plants. Most infested plants produced shorter canes and their lengths appeared to have a strong negative correlation with the highest mite density in four cultivars; canes of Sahebi Uroomie did not appear affected. At the highest mite density, canes of Khalili Bovanat and Sahebi Uroomie displayed the most and the least shortening effects, respectively. The percentage of leaves with erinea, as well as the number of erinea per leaves and the diameter of erinea increased along with the mite population density. The mite densities in buds (April 2014) and on leaves with erinea (in November 2013) were higher at the highest treatment level in the medium-late (Rishbaba) and late ripening (Sezdang Ghalat) cultivars, than in the early and early-medium ripening ones. Almost all data collected in the current experiment allowed the conclusion that Sahebi Uroomie and Shahani were less affected than the other cultivars (Khalili Bovanat, Rishbaba and Sezdang Ghalat). [ABSTRACT FROM AUTHOR]

The erineum strain of Colomerus vitis (GEM) is the most destructive pest of vineyards in western Iran and sometimes causes considerable damages to the grapevine. Little information is available on the susceptibility of the grapevine to this pest and its knowledge can be useful for a sustainable management of GEM. The present study was aimed at evaluating the responses of the plants to the infestation of GEM in order to compare the resistance/susceptibility of some native cultivars to this pest. Also, the profiling of JA, SA and IAA in leaves of infested plants of Sezdang was studied. The experiment was carried out on eighteen native cultivars and the non-native Muscat Gordo which were selected amongst the most common in southern and western Iran. Potted plants were cultivated under greenhouse conditions at a temperature of 32 ± 3.8°C, 75 ± 5% R.H. and a photoperiod of L16: D8 h. The impact of GEM was evaluated on the basis of the leaf area and weight, number and size of the erinea, and percentage of leaves with erinea three months after the infestation. The cane length was measured, too. Mite density on galled leaves (three months after the infestation) and in buds (at the bud breaking) was assessed. Cluster analysis based on the leaf damage index induced by GEM allowed to distinguish highly affected (Sezdang, Khalili, Ghalati and Rishbaba), moderately affected (Neyshaboori, Gazne, Muscat, Lale, Shahani Sefid, Ahmad, Monagha and Sia) and scarcely affected (Yaghuti, Rotabi, White Thompson, Atabaki, Koladari and Sahebi and Shahani Gerd) cultivars. The mite density into the buds and on the galled leaves was higher in the medium-late (Rishbaba and Khalili) and late ripening (Sezdang and Ghalati) cultivars rather than in the early (Sahebi and Shahani Gerd) and early-medium (Atabaki) ripening ones. The leaf damaged area, the leaf weight, the shoot length and the erineum development were correlated to the mite density and were the highest on Sezdang, Khalili, Ghalati and Rishbaba and the lowest on Atabaki, Koladari, Sahebi and Shahani Gerd. The highest density of the overwintering population was detected in proximal buds of all treated cultivars. The plant responses and the mite density were investigated also in the second and third year after the first mite infestation on highly affected (Sezdang, Khalili, Ghalati, Rishbaba), a few of the moderately affected (Neyshaboori, Gazne, Muscat) and the scarcely affected cultivars (White Thompson, Atabaki, Koladari, Sahebi, Shahani Gerd). The leaf damaged area, the percentage of galled leaves, the percentage of cane length reduction and the mite density strongly decreased during all three years of observations on the highly affected Sezdang, Khalili and Gazne. On the contrary, Ghalati and Rishbaba displayed an increase of the leaf damaged area, leaf damaged index and mite density on galled leaves during the same period in comparison to the first year of observation. The percentage of the leaves with erinea, the leaf damaged area and the mite density of Sezdang were highly and positively correlated with IAA while a negative correlation was found between the leaf damaged area and the mite density with SA and JA in the assayed years. Almost all data currently collected allowed a recognition of White Thompson, Atabaki, Koladari, Sahebi and Shahani Gerd as the least affected cultivars. [ABSTRACT FROM AUTHOR]

In southern Brazil, the recent increase in tropospheric ozone (O 3 ) concentrations poses an additional threat to the biodiverse but endangered and fragmented remnants of the Atlantic Forest. Given the mostly unknown sensitivity of tropical species to oxidative stress, the principal objective of this study was to determine whether the current O 3 levels in the Metropolitan Region of Campinas (MRC), downwind of São Paulo, affect the native vegetation of forest remnants. Foliar responses to O 3 of three tree species typical of the MRC forests were investigated using indoor chamber exposure experiments under controlled conditions and a field survey. Exposure to 70 ppb O 3 reduced assimilation and leaf conductance but increased respiration in Astronium graveolens while gas exchange in Croton floribundus was little affected. Both A. graveolens and Piptadenia gonoacantha developed characteristic O 3 -induced injury in the foliage, similar to visible symptoms observed in > 30% of trees assessed in the MRC, while C. floribundus remained asymptomatic. The underlying structural symptoms in both O 3 -exposed and field samples were indicative of oxidative burst, hypersensitive responses, accelerated cell senescence and, primarily in field samples, interaction with photo-oxidative stress. The markers of O 3 stress were thus mostly similar to those observed in other regions of the world. Further research is needed, to estimate the proportion of sensitive forest species, the O 3 impact on tree growth and stand stability and to detect O 3 hot spots where woody species in the Atlantic Forest are mostly affected. [ABSTRACT FROM AUTHOR]

There is growing interest in sugarcane straw removal from the field to use as raw material for bioenergy production. In contrast, sugarcane straw removal may have negative implications for many soil ecosystem services and subsequent plant growth. A two-year experiment was conducted at Bom Retiro and Univalem mills within the dry and wet seasons for assessing the impact of straw rates removal on plant production. The experimental design was randomized blocks with five treatments proportional to 0, 25, 50, 75 and 100% of straw removal. Plant parameters evaluated included: tillering, phytomass accumulation, stalk yield and stalk industrial quality. Straw removal increased plant tillering at Bom Retiro mill in both seasons and within dry season at Univalem mill, however the plant population at the end of each ratoon cycle was not affected by straw management. Phytomass yield across each ratoon cycle was fit to a sigmoidal model (R 2 ≥ 0.92, p < 0.05). Time necessary for plant completes its lag-phase is higher at the treatments applied in the dry season, whereas there was no time-pattern for plants to complete the linear and stationary growth phases. Moderate amounts of straw: 4–9 Mg ha −1 (dry base) on soil surface enhanced stalk yield. Different rates of straw removal did not affect stalk industrial quality. Overall, partial straw removal, at least in the short-term, could be a win–win situation, sustaining sugarcane yields and providing feedstock for bioelectricity cogeneration and/or 2G-ethanol production. [ABSTRACT FROM AUTHOR]

Environmental stresses pose a significant threat to plant growth and ecosystem productivity, particularly in arid lands that are more susceptible to climate change. Strigolactones (SLs), carotenoid-derived plant hormones, have emerged as a potential tool for mitigating environmental stresses. This review aimed to gather information on SLs' role in enhancing plant tolerance to ecological stresses and their possible use in improving the resistance mechanisms of arid land plant species to intense aridity in the face of climate change. Roots exude SLs under different environmental stresses, including macronutrient deficiency, especially phosphorus (P), which facilitates a symbiotic association with arbuscular mycorrhiza fungi (AMF). SLs, in association with AMF, improve root system architecture, nutrient acquisition, water uptake, stomatal conductance, antioxidant mechanisms, morphological traits, and overall stress tolerance in plants. Transcriptomic analysis revealed that SL-mediated acclimatization to abiotic stresses involves multiple hormonal pathways, including abscisic acid (ABA), cytokinins (CK), gibberellic acid (GA), and auxin. However, most of the experiments have been conducted on crops, and little attention has been paid to the dominant vegetation in arid lands that plays a crucial role in reducing soil erosion, desertification, and land degradation. All the environmental gradients (nutrient starvation, drought, salinity, and temperature) that trigger SL biosynthesis/exudation prevail in arid regions. The above-mentioned functions of SLs can potentially be used to improve vegetation restoration and sustainable agriculture. Present review concluded that knowledge on SL-mediated tolerance in plants is developed, but still in-depth research is needed on downstream signaling components in plants, SL molecular mechanisms and physiological interactions, efficient methods of synthetic SLs production, and their effective application in field conditions. This review also invites researchers to explore the possible application of SLs in improving the survival rate of indigenous vegetation in arid lands, which can potentially help combat land degradation problems. [ABSTRACT FROM AUTHOR]