Pub Date : 2025-09-17DOI: 10.1016/j.envexpbot.2025.106242
Yunke Chen , Elias Kaiser , Ep Heuvelink , Kai Cao , Zhonghua Bian , Qichang Yang , Leo F.M. Marcelis
It is increasingly evident that green light (500–600 nm) affects plant growth, but the varying effects of different regions within this waveband remain unclear. We investigated how different regions of green light affect lettuce (Lactuca sativa) growth, morphology and physiology. Lettuce was grown in a climate chamber with red/blue light as a reference treatment. In three green light treatments, 28 % of the red/blue light was replaced by green light. A higher fraction of green light logically meant a lower fraction of red and blue light. The green light was provided either by narrowband green LEDs peaking at 515 nm or 550 nm, or by a broadband green LED. In all treatments, light intensity was 212 μmol m−2 s−1. After 21 days of growth, shoot biomass (+14–29 %) and height (+16–18 %) increased in all green light treatments compared to the reference, while leaf photosynthetic gas exchange and pigmentation remained unchanged. The largest biomass (+29 %) and leaf area (+18 %) were obtained in the narrowband green light treatment peaking at 550 nm. We conclude that the increase in lettuce biomass was not caused by a higher carbon assimilation per leaf area but may instead be explained by improved light distribution within the canopy. Our results suggest that specific regions in the green light waveband are more beneficial to lettuce growth than others.
{"title":"Palette of green: Exploring the effects of different wavelengths of green light on biomass and morphology in lettuce (Lactuca sativa)","authors":"Yunke Chen , Elias Kaiser , Ep Heuvelink , Kai Cao , Zhonghua Bian , Qichang Yang , Leo F.M. Marcelis","doi":"10.1016/j.envexpbot.2025.106242","DOIUrl":"10.1016/j.envexpbot.2025.106242","url":null,"abstract":"<div><div>It is increasingly evident that green light (500–600 nm) affects plant growth, but the varying effects of different regions within this waveband remain unclear. We investigated how different regions of green light affect lettuce (<em>Lactuca sativa</em>) growth, morphology and physiology. Lettuce was grown in a climate chamber with red/blue light as a reference treatment. In three green light treatments, 28 % of the red/blue light was replaced by green light. A higher fraction of green light logically meant a lower fraction of red and blue light. The green light was provided either by narrowband green LEDs peaking at 515 nm or 550 nm, or by a broadband green LED. In all treatments, light intensity was 212 μmol m<sup>−2</sup> s<sup>−1</sup>. After 21 days of growth, shoot biomass (+14–29 %) and height (+16–18 %) increased in all green light treatments compared to the reference, while leaf photosynthetic gas exchange and pigmentation remained unchanged. The largest biomass (+29 %) and leaf area (+18 %) were obtained in the narrowband green light treatment peaking at 550 nm. We conclude that the increase in lettuce biomass was not caused by a higher carbon assimilation per leaf area but may instead be explained by improved light distribution within the canopy. Our results suggest that specific regions in the green light waveband are more beneficial to lettuce growth than others.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"238 ","pages":"Article 106242"},"PeriodicalIF":4.7,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145118090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-13DOI: 10.1016/j.envexpbot.2025.106240
Natalia Krówczyńska, Małgorzata Pietrowska-Borek
Heavy metals (HMs), pollutants produced by humans, significantly impact crop yields. The contamination of soil and water by HMs poses a serious environmental challenge. Although HMs naturally occur in the soil as rare elements, agricultural practices, refuse dumping, metallurgy, and manufacturing contribute to their environmental spread in higher concentrations that lead to negative effects on crop plants and human health. Even at low concentrations, HMs, such as cadmium (Cd), lead (Pb), and aluminum (Al), adversely impact root uptake and transport to vegetative and reproductive organs, disrupting mineral nutrition and homeostasis, which in turn influence the growth and development of both plant shoots and roots. Plants absorb HMs from contaminated soil or water, which inhibits root growth, causes leaf chlorosis, hinders stomatal opening, and can lead to wilting or death. Additionally, it suppresses photosynthesis and transpiration, induces oxidative stress, alters enzyme activity, and modifies gene expression. Resource allocation between growth and defense is a key trade-off for plant survival and fitness. Under heavy metal exposure, stronger defense responses often coincide with reduced growth, even without visible damage. Plants have evolved complex signaling networks that respond to environmental stimuli through signaling proteins, such as plasma membrane receptors and ion transporters, as well as cascades of kinases and other enzymes, ultimately leading to the activation of effectors. In the plant response to HMs stress, the pivotal signaling role is played by hormones and many additional compounds, including second messengers such as cytosolic Ca2 + , reactive oxygen species (ROS), reactive nitrogen species (RNS), and cyclic nucleotides such as cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). Moreover, it has recently been demonstrated that nucleotides such as exogenous ATP (eATP) can also play signaling roles in plant cells. These are part of the regulatory network, involving MAP kinase, SnRK, and transcription factors, that leads to the synthesis of metabolites capable of mitigating plant stress caused by HMs. Their uptake triggers diverse epigenetic mechanisms that may either promote or hinder plant stress tolerance. In response to HMs exposure, plants adjust gene expression through DNA methylation, histone acetylation, and microRNA-mediated gene silencing. Recent findings also highlight the involvement of epigenetic mechanisms as important post-transcriptional regulators within this signaling network, further fine-tuning plant responses to HMs. However, more research is still needed to identify the signaling networks involved in this process. This review summarizes the current understanding of perception, signal transduction, and plant responses to Cd, Pb, and Al stress.
{"title":"From signal perception to adaptive responses: A comprehensive review of plant mechanisms under cadmium, lead, and aluminum stress","authors":"Natalia Krówczyńska, Małgorzata Pietrowska-Borek","doi":"10.1016/j.envexpbot.2025.106240","DOIUrl":"10.1016/j.envexpbot.2025.106240","url":null,"abstract":"<div><div>Heavy metals (HMs), pollutants produced by humans, significantly impact crop yields. The contamination of soil and water by HMs poses a serious environmental challenge. Although HMs naturally occur in the soil as rare elements, agricultural practices, refuse dumping, metallurgy, and manufacturing contribute to their environmental spread in higher concentrations that lead to negative effects on crop plants and human health. Even at low concentrations, HMs, such as cadmium (Cd), lead (Pb), and aluminum (Al), adversely impact root uptake and transport to vegetative and reproductive organs, disrupting mineral nutrition and homeostasis, which in turn influence the growth and development of both plant shoots and roots. Plants absorb HMs from contaminated soil or water, which inhibits root growth, causes leaf chlorosis, hinders stomatal opening, and can lead to wilting or death. Additionally, it suppresses photosynthesis and transpiration, induces oxidative stress, alters enzyme activity, and modifies gene expression. Resource allocation between growth and defense is a key trade-off for plant survival and fitness. Under heavy metal exposure, stronger defense responses often coincide with reduced growth, even without visible damage. Plants have evolved complex signaling networks that respond to environmental stimuli through signaling proteins, such as plasma membrane receptors and ion transporters, as well as cascades of kinases and other enzymes, ultimately leading to the activation of effectors. In the plant response to HMs stress, the pivotal signaling role is played by hormones and many additional compounds, including second messengers such as cytosolic Ca<sup>2 +</sup> , reactive oxygen species (ROS), reactive nitrogen species (RNS), and cyclic nucleotides such as cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). Moreover, it has recently been demonstrated that nucleotides such as exogenous ATP (eATP) can also play signaling roles in plant cells. These are part of the regulatory network, involving MAP kinase, SnRK, and transcription factors, that leads to the synthesis of metabolites capable of mitigating plant stress caused by HMs. Their uptake triggers diverse epigenetic mechanisms that may either promote or hinder plant stress tolerance. In response to HMs exposure, plants adjust gene expression through DNA methylation, histone acetylation, and microRNA-mediated gene silencing. Recent findings also highlight the involvement of epigenetic mechanisms as important post-transcriptional regulators within this signaling network, further fine-tuning plant responses to HMs. However, more research is still needed to identify the signaling networks involved in this process. This review summarizes the current understanding of perception, signal transduction, and plant responses to Cd, Pb, and Al stress.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"238 ","pages":"Article 106240"},"PeriodicalIF":4.7,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145118187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-13DOI: 10.1016/j.envexpbot.2025.106241
Mingming Wang , Zihan Kan , Tingting Hui , Boyi Song , Huiliang Liu , Benfeng Yin , Ye Tao , Xiaoying Rong , Wei Hang , Yuanming Zhang , Xiaobing Zhou
Non-structural carbohydrates (NSC) are critical indicators of the carbon acquisition and consumption balance in vascular plants, and are equally important for biological soil crusts (BSCs), which serve as significant carbon sinks in arid regions. Nitrogen (N) deposition significantly alters NSC storage by affecting plant growth, photosynthesis, and the carbon-to-nitrogen ratio. However, the response of NSC to N deposition may vary across different developmental stages of BSCs due to differences in physiological structures and soil properties. We conducted a long-term field N addition experiment (2010–2021) in the Gurbantunggut Desert, with N rates from 0 to 3 g m⁻² yr⁻¹ and a 2:1 NH₄⁺-N to NO₃⁻-N ratio, to examine the effects of N on NSC and their components (fructose, sucrose, soluble sugars, and starch) in three BSC types: cyanobacterial, lichen, and moss crusts. Our results revealed that the development of BSCs from cyanobacterial to lichen and moss crusts significantly alters NSC allocation, with an increasing ratio of soluble sugars to starch (0.24–1–1.68). As N added levels rise, NSC content in all three BSC types exhibits a nonlinear trend, characterized by low promotion and high inhibition, with distinct threshold points (N1.5-N0.5-N0.5). This phenomenon arises from shifts in the NSC driving factors under N addition: transitioning from soil nutrient dependence (cyanobacteria) to regulation by plant antioxidant enzyme activity (lichen), and ultimately to a more complex physiological regulation involving photosynthetic pigments and antioxidant enzyme activities (Moss). This study reveals the transition of BSCs from “environmental adapters” to “ecological regulators” throughout their successional stages. These findings provide new insights into the C metabolism of BSCs and have important implications for ecological restoration in N-impacted arid regions.
{"title":"The development of biological soil crusts reshapes the strategies of non-structural carbohydrates in response to nitrogen deposition","authors":"Mingming Wang , Zihan Kan , Tingting Hui , Boyi Song , Huiliang Liu , Benfeng Yin , Ye Tao , Xiaoying Rong , Wei Hang , Yuanming Zhang , Xiaobing Zhou","doi":"10.1016/j.envexpbot.2025.106241","DOIUrl":"10.1016/j.envexpbot.2025.106241","url":null,"abstract":"<div><div>Non-structural carbohydrates (NSC) are critical indicators of the carbon acquisition and consumption balance in vascular plants, and are equally important for biological soil crusts (BSCs), which serve as significant carbon sinks in arid regions. Nitrogen (N) deposition significantly alters NSC storage by affecting plant growth, photosynthesis, and the carbon-to-nitrogen ratio. However, the response of NSC to N deposition may vary across different developmental stages of BSCs due to differences in physiological structures and soil properties. We conducted a long-term field N addition experiment (2010–2021) in the Gurbantunggut Desert, with N rates from 0 to 3 g m⁻² yr⁻¹ and a 2:1 NH₄⁺-N to NO₃⁻-N ratio, to examine the effects of N on NSC and their components (fructose, sucrose, soluble sugars, and starch) in three BSC types: cyanobacterial, lichen, and moss crusts. Our results revealed that the development of BSCs from cyanobacterial to lichen and moss crusts significantly alters NSC allocation, with an increasing ratio of soluble sugars to starch (0.24–1–1.68). As N added levels rise, NSC content in all three BSC types exhibits a nonlinear trend, characterized by low promotion and high inhibition, with distinct threshold points (N1.5-N0.5-N0.5). This phenomenon arises from shifts in the NSC driving factors under N addition: transitioning from soil nutrient dependence (cyanobacteria) to regulation by plant antioxidant enzyme activity (lichen), and ultimately to a more complex physiological regulation involving photosynthetic pigments and antioxidant enzyme activities (Moss). This study reveals the transition of BSCs from “environmental adapters” to “ecological regulators” throughout their successional stages. These findings provide new insights into the C metabolism of BSCs and have important implications for ecological restoration in N-impacted arid regions.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"238 ","pages":"Article 106241"},"PeriodicalIF":4.7,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-12DOI: 10.1016/j.envexpbot.2025.106238
L. Erik Daber , Philipp Nolte , Jürgen Kreuzwieser , Mirjam Meischner , Jonathan Williams , Christiane Werner
Chiral forms of monoterpenes and their enantiomeric composition are of ecological significance, e.g. for plant-insect interactions. However, biosynthetic pathways and drought-induced changes of enantiomeric monoterpene emissions are barely understood. We analyzed, for the first time, drought effects on the enantiomeric composition of de novo vs. storage emitted monoterpenes from Norway spruce saplings by position-specific 13C-pyruvate (13C2- and 13C1-labelled) feeding and 13CO2 fumigation. Drought reduced total monoterpene emissions already during its early stages, strongly linked to net photosynthesis, and lead to a decline in de novo synthesis of monoterpenes. However, it unevenly affected chiral monoterpenes, leading to compositional changes of emissions with increasing drought. At the onset of drought, the (-)-enantiomers of limonene, β-phellandrene, α- and β-pinene were emitted at higher rates than the (+)-enantiomers. Our results suggest that (-)-enantiomers were emitted mainly from storage pools while emissions of (+)-enantiomers rather depended on de novo biosynthesis. Even though biosynthesis of different monoterpenes derives from the same precursor pool, isotopic label incorporation revealed three groups among monoterpenes: storage derived, dominantly labelled via 13C2-pyruvate, and dominantly labelled via 13CO2-fumigation. Our results contribute to a growing amount of evidence of high flexibility in metabolic pathways of monoterpene biosynthesis in plant cells.
{"title":"Position-specific isotope labelling gives new insights into chiral monoterpene synthesis of Norway spruce (Picea abies L.)","authors":"L. Erik Daber , Philipp Nolte , Jürgen Kreuzwieser , Mirjam Meischner , Jonathan Williams , Christiane Werner","doi":"10.1016/j.envexpbot.2025.106238","DOIUrl":"10.1016/j.envexpbot.2025.106238","url":null,"abstract":"<div><div>Chiral forms of monoterpenes and their enantiomeric composition are of ecological significance, e.g. for plant-insect interactions. However, biosynthetic pathways and drought-induced changes of enantiomeric monoterpene emissions are barely understood. We analyzed, for the first time, drought effects on the enantiomeric composition of <em>de novo</em> vs. storage emitted monoterpenes from Norway spruce saplings by position-specific <sup>13</sup>C-pyruvate (<sup>13</sup>C2- and <sup>13</sup>C1-labelled) feeding and <sup>13</sup>CO<sub>2</sub> fumigation. Drought reduced total monoterpene emissions already during its early stages, strongly linked to net photosynthesis, and lead to a decline in <em>de novo</em> synthesis of monoterpenes. However, it unevenly affected chiral monoterpenes, leading to compositional changes of emissions with increasing drought. At the onset of drought, the (-)-enantiomers of limonene, β-phellandrene, α- and β-pinene were emitted at higher rates than the (+)-enantiomers. Our results suggest that (-)-enantiomers were emitted mainly from storage pools while emissions of (+)-enantiomers rather depended on <em>de novo</em> biosynthesis. Even though biosynthesis of different monoterpenes derives from the same precursor pool, isotopic label incorporation revealed three groups among monoterpenes: storage derived, dominantly labelled via <sup>13</sup>C2-pyruvate, and dominantly labelled via <sup>13</sup>CO<sub>2</sub>-fumigation. Our results contribute to a growing amount of evidence of high flexibility in metabolic pathways of monoterpene biosynthesis in plant cells.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"238 ","pages":"Article 106238"},"PeriodicalIF":4.7,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-11DOI: 10.1016/j.envexpbot.2025.106239
Wuttisak Sarikhit , Yang Bi , Zhi-Yong Wang , Juthamas Chaiwanon
Silver nanoparticles (AgNP) are incorporated into numerous consumer products for their antimicrobial and conductive properties. Despite the widespread use, the environmental implications of AgNP leakage, particularly on plant growth, remain underexplored. This study examined the effects of AgNP on root growth. Arabidopsis seedlings grown on vertical agar plates supplemented with AgNP showed a wavy root phenotype, which is caused by asymmetric growth at the root tips. The results showed that AgNP inhibited primary root growth and induced root waving in a dose-dependent manner; such effects were absent in seedlings treated with equivalent concentrations of silver ions (Ag+), indicating the unique impact of AgNP. Using auxin signaling mutants, we demonstrated that AgNP-induced root waving depends on functional auxin signaling. Analysis of auxin reporter lines revealed that AgNP disrupted normal auxin distribution and induce asymmetric auxin accumulation by interfering with polar auxin transport, specifically through downregulation of auxin efflux and influx carrier expression in the root tip —except for PIN2, which was upregulated in the epidermis and cortex. Furthermore, inhibition of TAA1-mediated local auxin biosynthesis using kynurenine, as well as mutation of the TAA1 gene, exacerbated the root waving phenotype under AgNP treatment. Together, these findings reveal that AgNP modulates root growth and waving by interfering with auxin homeostasis and transport, highlighting a potential ecological risk posed by nanoparticle contamination in the environment.
{"title":"Silver nanoparticles inhibit root growth and promote root waving by inhibiting polar auxin transport and local auxin biosynthesis in Arabidopsis root tips","authors":"Wuttisak Sarikhit , Yang Bi , Zhi-Yong Wang , Juthamas Chaiwanon","doi":"10.1016/j.envexpbot.2025.106239","DOIUrl":"10.1016/j.envexpbot.2025.106239","url":null,"abstract":"<div><div>Silver nanoparticles (AgNP) are incorporated into numerous consumer products for their antimicrobial and conductive properties. Despite the widespread use, the environmental implications of AgNP leakage, particularly on plant growth, remain underexplored. This study examined the effects of AgNP on root growth. Arabidopsis seedlings grown on vertical agar plates supplemented with AgNP showed a wavy root phenotype, which is caused by asymmetric growth at the root tips. The results showed that AgNP inhibited primary root growth and induced root waving in a dose-dependent manner; such effects were absent in seedlings treated with equivalent concentrations of silver ions (Ag<sup>+</sup>), indicating the unique impact of AgNP. Using auxin signaling mutants, we demonstrated that AgNP-induced root waving depends on functional auxin signaling. Analysis of auxin reporter lines revealed that AgNP disrupted normal auxin distribution and induce asymmetric auxin accumulation by interfering with polar auxin transport, specifically through downregulation of auxin efflux and influx carrier expression in the root tip —except for <em>PIN2</em>, which was upregulated in the epidermis and cortex. Furthermore, inhibition of TAA1-mediated local auxin biosynthesis using kynurenine, as well as mutation of the <em>TAA1</em> gene, exacerbated the root waving phenotype under AgNP treatment. Together, these findings reveal that AgNP modulates root growth and waving by interfering with auxin homeostasis and transport, highlighting a potential ecological risk posed by nanoparticle contamination in the environment.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"238 ","pages":"Article 106239"},"PeriodicalIF":4.7,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145045675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-09DOI: 10.1016/j.envexpbot.2025.106237
Lei Ouyang , Longwei Lu , Jingyi Wang , Ping Zhao
Chronic acid deposition has induced severe soil acidification, leading to the depletion of calcium (Ca) and the accumulation of phytotoxic aluminum (Al). Ca is essential for sensing water stress, strengthening cellular structures, and enhancing plant water use efficiency (WUE), while Al impairs root function. Consequently, the altered soil Ca and Al dynamics are likely to produce divergent impacts on plant water use and WUE, yet the underlying mechanisms remain poorly understood. To investigate this, we conducted a manipulative field experiment simulating soil acidification (Acid) and calcium amendment (Ca) in a secondary evergreen broadleaved forest in South China from 2022 to 2024. We continuously monitored sap flow-based transpiration and analyzed the δ¹ ³C-derived intrinsic WUE (WUEi) in four dominant species: Pyrenaria macrocarpa, Quercus myrsinifolia, Aporosa dioica, and Castanopsis fissa. Additionally, we conducted periodic ecophysiological measurements, including soil and leaf stoichiometry, leaf water potential, and stomatal conductance. The results showed that species-specific responses to Acid and Ca treatments. P. macrocarpa exhibited no significant change in transpiration under the Acid treatment in 2022 and 2023 but showed a significant decline in 2024, suggesting a delayed toxicity effect from accumulated Al. In contrast, A. dioica consistently showed increased transpiration under the Acid treatment, potentially reflecting an adaptive strategy to maintain nutrient uptake and support photosynthesis in acidic soils. Both species showed a significant increase in WUEi with Ca amendment, positively correlating with soil Ca content and leaf Ca/Al ratio. In comparison, Q. myrsinifolia and C. fissa displayed no significant physiological responses to either treatment. These findings highlight the divergent strategies adopted by co-occurring dominant species in response to acid deposition and Ca amendment. Prolonged acid deposition may threaten species like P. macrocarpa, while species with high photosynthetic and water demands, such as A. dioica and C. fissa, may face increased risk of hydraulic failure under the combined stressors of acidification and drought.
{"title":"Divergent responses to acid deposition and calcium addition in a subtropical secondary evergreen broadleaved forest: Experimental evidence from transpiration and water use efficiency dynamics","authors":"Lei Ouyang , Longwei Lu , Jingyi Wang , Ping Zhao","doi":"10.1016/j.envexpbot.2025.106237","DOIUrl":"10.1016/j.envexpbot.2025.106237","url":null,"abstract":"<div><div>Chronic acid deposition has induced severe soil acidification, leading to the depletion of calcium (Ca) and the accumulation of phytotoxic aluminum (Al). Ca is essential for sensing water stress, strengthening cellular structures, and enhancing plant water use efficiency (WUE), while Al impairs root function. Consequently, the altered soil Ca and Al dynamics are likely to produce divergent impacts on plant water use and WUE, yet the underlying mechanisms remain poorly understood. To investigate this, we conducted a manipulative field experiment simulating soil acidification (Acid) and calcium amendment (Ca) in a secondary evergreen broadleaved forest in South China from 2022 to 2024. We continuously monitored sap flow-based transpiration and analyzed the <em>δ</em>¹ ³C-derived intrinsic WUE (WUEi) in four dominant species: <em>Pyrenaria macrocarpa</em>, <em>Quercus myrsinifolia</em>, <em>Aporosa dioica</em>, and <em>Castanopsis fissa</em>. Additionally, we conducted periodic ecophysiological measurements, including soil and leaf stoichiometry, leaf water potential, and stomatal conductance. The results showed that species-specific responses to Acid and Ca treatments. <em>P. macrocarpa</em> exhibited no significant change in transpiration under the Acid treatment in 2022 and 2023 but showed a significant decline in 2024, suggesting a delayed toxicity effect from accumulated Al. In contrast, <em>A. dioica</em> consistently showed increased transpiration under the Acid treatment, potentially reflecting an adaptive strategy to maintain nutrient uptake and support photosynthesis in acidic soils. Both species showed a significant increase in WUEi with Ca amendment, positively correlating with soil Ca content and leaf Ca/Al ratio. In comparison, <em>Q. myrsinifolia</em> and <em>C. fissa</em> displayed no significant physiological responses to either treatment. These findings highlight the divergent strategies adopted by co-occurring dominant species in response to acid deposition and Ca amendment. Prolonged acid deposition may threaten species like <em>P. macrocarpa</em>, while species with high photosynthetic and water demands, such as <em>A. dioica</em> and <em>C. fissa</em>, may face increased risk of hydraulic failure under the combined stressors of acidification and drought.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"238 ","pages":"Article 106237"},"PeriodicalIF":4.7,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-08DOI: 10.1016/j.envexpbot.2025.106235
Yuta Miyoshi , Shota Teramoto , Fumiyuki Soma , Yong-Gen Yin , Nobuo Suzui , Yusaku Noda , Kazuyuki Enomoto , Naoki Kawachi , Joseph Peller , Eiji Yoshida , Hideaki Tashima , Taiga Yamaya , Yusaku Uga
This study investigated the dynamics of 11C-labeled photosynthate translocation in nodulated and non-nodulated soybean plants across three time windows: during the low water condition, and at 0–3 h and 4–7 h after the recover water content. Advanced imaging techniques, including positron emission tomography (PET) and X-ray computed tomography (X-ray CT), enabled three-dimensional visualization of root structures and carbon allocation patterns. Under low water condition, nodulated soybeans prioritized carbon translocation to taproots and nodules. Using logistic modeling of ¹¹C accumulation, Vmax (steepest slope; maximum translocation rate) and Kmax (asymptote; accumulation capacity) were calculated. In nodulated plants, Vmax at lateral root tips increased by 56 % during 0–3 h after rewatering relative to the low-water condition; during 4–7 h, Vmax and Kmax at middle-layer nodules increased by 55 % and 49 %, respectively. Collectively, these results indicate a temporal reorganization of sink activity after rewatering—from lateral root tips early to middle-layer nodules later. These observations are consistent with a role for nodules as prominent sinks that may facilitate the redistribution of photosynthates after rewatering, whereas non-nodulated plants showed decreases in Vmax and Kmax across root regions under low-water conditions and exhibited little recovery during 0–3 and 4–7 h after rewatering. These patterns are consistent with a role for nodules in facilitating the reactivation and redistribution of carbon sinks under changing water availability. This study clarifies how water status modulates belowground carbon allocation in soybean and provides a basis for evaluating nodule-associated sink behavior under fluctuating moisture. These insights may inform crop management and guide breeding strategies aimed at improving resilience to water variability.
{"title":"Root nodule presence alters the dynamics of photosynthate translocation under varying soil moisture conditions","authors":"Yuta Miyoshi , Shota Teramoto , Fumiyuki Soma , Yong-Gen Yin , Nobuo Suzui , Yusaku Noda , Kazuyuki Enomoto , Naoki Kawachi , Joseph Peller , Eiji Yoshida , Hideaki Tashima , Taiga Yamaya , Yusaku Uga","doi":"10.1016/j.envexpbot.2025.106235","DOIUrl":"10.1016/j.envexpbot.2025.106235","url":null,"abstract":"<div><div>This study investigated the dynamics of <sup>11</sup>C-labeled photosynthate translocation in nodulated and non-nodulated soybean plants across three time windows: during the low water condition, and at 0–3 h and 4–7 h after the recover water content. Advanced imaging techniques, including positron emission tomography (PET) and X-ray computed tomography (X-ray CT), enabled three-dimensional visualization of root structures and carbon allocation patterns. Under low water condition, nodulated soybeans prioritized carbon translocation to taproots and nodules. Using logistic modeling of ¹¹C accumulation, <em>Vmax</em> (steepest slope; maximum translocation rate) and <em>Kmax</em> (asymptote; accumulation capacity) were calculated. In nodulated plants, <em>Vmax</em> at lateral root tips increased by 56 % during 0–3 h after rewatering relative to the low-water condition; during 4–7 h, <em>Vmax</em> and <em>Kmax</em> at middle-layer nodules increased by 55 % and 49 %, respectively. Collectively, these results indicate a temporal reorganization of sink activity after rewatering—from lateral root tips early to middle-layer nodules later. These observations are consistent with a role for nodules as prominent sinks that may facilitate the redistribution of photosynthates after rewatering, whereas non-nodulated plants showed decreases in <em>Vmax</em> and <em>Kmax</em> across root regions under low-water conditions and exhibited little recovery during 0–3 and 4–7 h after rewatering. These patterns are consistent with a role for nodules in facilitating the reactivation and redistribution of carbon sinks under changing water availability. This study clarifies how water status modulates belowground carbon allocation in soybean and provides a basis for evaluating nodule-associated sink behavior under fluctuating moisture. These insights may inform crop management and guide breeding strategies aimed at improving resilience to water variability.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"238 ","pages":"Article 106235"},"PeriodicalIF":4.7,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-04DOI: 10.1016/j.envexpbot.2025.106234
Dadong Li , Mengjie Tian , Wei Ding , El-Hadji Malick Cisse , Lingfeng Miao , Bingbing Ye , Mengqi Li , Yifan Long , Fan Yang
The leaves of mangroves are a key component of the plant biomass, and they have a prominent function in heavy metal accumulation from contaminated sediments, which modulates their functional traits. However, it remains unclear how mangrove leaf heavy metals coordinate with leaf traits at different tidal levels. Thus, two species, exotic Sonneratia apetala and native Bruguiera sexangula, were selected to perform a qualitative study that shed light on the mechanisms underlying mangrove leaf functional traits and heavy metal dynamics (As, Pb, Cd, Cr, and Cu) across different tidal levels. The results showed that with increasing tidal levels individual leaf weight and individual leaf area increased in B. sexangula but decreased in S. apetala. The B. sexangula showed a markedly higher capacity for heavy metal accumulation, sequestering metals in the spongy mesophyll, contrasting with S. apetala, which concentrated metals in the palisade mesophyll. Both species peaked in leaf heavy metal concentrations at mid-tidal levels, a phenomenon linked to specialized leaf structural adjustments, increased phytohormone levels (ZR, JA-Me, IAA and ABA), and amplified detoxification mechanisms, including reduced glutathione, non-protein thiols, glutathione-S-transferase, flavonoids, tannins, and anthocyanins, which were facilitated by acidic pH and Fe plaque deposition on roots. Partial least squares path modeling further suggested that phytohormones influenced metal accumulation indirectly by altering leaf anatomical features and boosting detoxification. These results highlight the importance of phytohormones' regulatory role in determining the variation of heavy metals in both species, which has significant implications for applications in using and selecting mangrove plants for phytoremediation.
{"title":"Dissecting possible correlations between leaf functional traits and heavy metal accumulation in two contrasting mangrove species across tidal gradients","authors":"Dadong Li , Mengjie Tian , Wei Ding , El-Hadji Malick Cisse , Lingfeng Miao , Bingbing Ye , Mengqi Li , Yifan Long , Fan Yang","doi":"10.1016/j.envexpbot.2025.106234","DOIUrl":"10.1016/j.envexpbot.2025.106234","url":null,"abstract":"<div><div>The leaves of mangroves are a key component of the plant biomass, and they have a prominent function in heavy metal accumulation from contaminated sediments, which modulates their functional traits. However, it remains unclear how mangrove leaf heavy metals coordinate with leaf traits at different tidal levels. Thus, two species, exotic <em>Sonneratia apetala</em> and native <em>Bruguiera sexangula</em>, were selected to perform a qualitative study that shed light on the mechanisms underlying mangrove leaf functional traits and heavy metal dynamics (As, Pb, Cd, Cr, and Cu) across different tidal levels. The results showed that with increasing tidal levels individual leaf weight and individual leaf area increased in <em>B. sexangula</em> but decreased in <em>S. apetala</em>. The <em>B. sexangula</em> showed a markedly higher capacity for heavy metal accumulation, sequestering metals in the spongy mesophyll, contrasting with <em>S. apetala</em>, which concentrated metals in the palisade mesophyll. Both species peaked in leaf heavy metal concentrations at mid-tidal levels, a phenomenon linked to specialized leaf structural adjustments, increased phytohormone levels (ZR, JA-Me, IAA and ABA), and amplified detoxification mechanisms, including reduced glutathione, non-protein thiols, glutathione-S-transferase, flavonoids, tannins, and anthocyanins, which were facilitated by acidic pH and Fe plaque deposition on roots. Partial least squares path modeling further suggested that phytohormones influenced metal accumulation indirectly by altering leaf anatomical features and boosting detoxification. These results highlight the importance of phytohormones' regulatory role in determining the variation of heavy metals in both species, which has significant implications for applications in using and selecting mangrove plants for phytoremediation.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"238 ","pages":"Article 106234"},"PeriodicalIF":4.7,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-03DOI: 10.1016/j.envexpbot.2025.106231
Grzegorz Wałpuski , Andrzej Rafalski , Marta Galas , Zygmunt Szefliński , Maksymilian Zienkiewicz
Ionizing radiation is one of the key physicochemical factors affecting living organisms, but its impact on unicellular algae remains poorly understood. Cyanidiophyceae are a class of extremophilic microalgae capable of thriving under the highly inhospitable conditions of volcanic hot springs. Among them, Galdieria sulphuraria is a unique species capable of mixotrophy, sexual reproduction, and exists in both haploid and diploid stages depending on environmental conditions. This study investigates, for the first time, the effects of ionizing radiation (2–6 kGy) on a representative extremophilic Cyanidiophyceae, focusing on radiation-induced damage and recovery in relation to ploidy. Our findings reveal that Galdieria sulphuraria in the diploid state exhibits extraordinary radiation resistance, surviving exposure to enormous doses as high as 6 kGy, making it one of the most radiation-tolerant photoautotrophic organisms known. Furthermore, diploids exhibit significantly higher tolerance than haploids, as evidenced by their superior survival, shorter duration of radiation sickness, enhanced synthesis of protective carotenoids, reduced oxidative damage, and high photosynthetic efficiency during recovery. These results provide novel insights into the role of ploidy in radiation resistance in algae and contribute to a broader understanding of extremophile adaptations. Given the relevance of ionizing radiation in astrobiology and space exploration, Galdieria sulphuraria emerges as a promising model for studying eukaryotic survival in extraterrestrial environments.
{"title":"Influence of ploidy on radiation resilience in extremophilic alga Galdieria sulphuraria under extreme ionizing conditions","authors":"Grzegorz Wałpuski , Andrzej Rafalski , Marta Galas , Zygmunt Szefliński , Maksymilian Zienkiewicz","doi":"10.1016/j.envexpbot.2025.106231","DOIUrl":"10.1016/j.envexpbot.2025.106231","url":null,"abstract":"<div><div>Ionizing radiation is one of the key physicochemical factors affecting living organisms, but its impact on unicellular algae remains poorly understood. <em>Cyanidiophyceae</em> are a class of extremophilic microalgae capable of thriving under the highly inhospitable conditions of volcanic hot springs. Among them, <em>Galdieria sulphuraria</em> is a unique species capable of mixotrophy, sexual reproduction, and exists in both haploid and diploid stages depending on environmental conditions. This study investigates, for the first time, the effects of ionizing radiation (2–6 kGy) on a representative extremophilic <em>Cyanidiophyceae,</em> focusing on radiation-induced damage and recovery in relation to ploidy. Our findings reveal that <em>Galdieria sulphuraria</em> in the diploid state exhibits extraordinary radiation resistance, surviving exposure to enormous doses as high as 6 kGy, making it one of the most radiation-tolerant photoautotrophic organisms known. Furthermore, diploids exhibit significantly higher tolerance than haploids, as evidenced by their superior survival, shorter duration of radiation sickness, enhanced synthesis of protective carotenoids, reduced oxidative damage, and high photosynthetic efficiency during recovery. These results provide novel insights into the role of ploidy in radiation resistance in algae and contribute to a broader understanding of extremophile adaptations. Given the relevance of ionizing radiation in astrobiology and space exploration, <em>Galdieria sulphuraria</em> emerges as a promising model for studying eukaryotic survival in extraterrestrial environments.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":"240 ","pages":"Article 106231"},"PeriodicalIF":4.7,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145476005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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