Tree physiology最新文献

{"title":"Pines compensate for winter insect defoliation with longer and more photosynthetically efficient needles.","authors":"Hermine Houdas, José Miguel Olano, Beatriz Fernández-Marín, José Ignacio García-Plazaola, Gabriel Sangüesa-Barreda","doi":"10.1093/treephys/tpag062","DOIUrl":"https://doi.org/10.1093/treephys/tpag062","url":null,"abstract":"<p><p>Insect outbreaks are major biotic disturbances in forest ecosystems. Defoliating insects reduce leaf area, limiting photosynthetic capacity and resource availability for physiological functions and foliage regrowth. This is particularly critical in evergreen conifers that store resources in older foliage and have high leaf construction costs. Understanding structural and physiological adjustments in new foliage following defoliation is essential to assess tree resilience and ecosystem recovery. We examined the effects of pine processionary moth (PPM, Thaumetopoea pityocampa) defoliation on Pinus nigra leaf functional traits in two stands in north-central Spain. In 2023, we collected branches from a total of 38 trees with contrasting degrees of defoliation and measured needle length, width, number of stomatal rows, and stomatal density on needles formed following the defoliation event. We also recorded physiological traits, including the maximum quantum yield of PSII (Fv/Fm; July and September), stomatal conductance (gs) and net photosynthetic assimilation rate (An; September; n = 18 trees). Additionally, we measured needle length, width, and Fv/Fm of needles produced prior to the defoliation event (1-year-old needles). Linear mixed models and a structural equation model were employed to analyze both direct and indirect effects of defoliation on structural traits, while general and generalized linear models were used to assess physiological changes. Defoliated trees produced longer new needles, suggesting a strategic allocation of resources toward crown recovery. Stomatal rows and density did not vary with defoliation but were instead related to needle width. Fv/Fm was unaffected by defoliation. Finally, defoliated trees showed higher An values without concomitant changes in gs, indicating a mechanism of photosynthetic upregulation that is not hydraulically mediated but might be driven by greater resource allocation. Together, these results suggest that Pinus nigra can partially compensate for canopy loss through structural and physiological adjustments, although complete defoliation may compromise tree resilience.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147857386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transcriptomic and Metabolomic Joint Analysis to Explore the Molecular Mechanisms of Different Resistant Poplar Varieties in Response to the Feeding Damage of Anoplophora glabripennis.","authors":"Zhiyuan Niu, Yongliang Yuan, Shaofei Tong, Haiyan Cui, Hong He, Junfeng Fan, Kailang Yang","doi":"10.1093/treephys/tpag058","DOIUrl":"https://doi.org/10.1093/treephys/tpag058","url":null,"abstract":"<p><p>In China, Asian longhorned beetle (ALB) infestations severely threaten poplar resources, the primary species used for shelterbelt afforestation. Two fast-growing poplar hybrids, Populus alba × (P. alba × P. glandulosa) (QB3) and P. nigra × P. deltoids (Ta), exhibit contrasting ALB resistance: QB3 is resistant, while Ta is highly susceptible. To elucidate the underlying molecular mechanisms, we examined transcriptome and metabolome changes in QB3 and Ta after ALB feeding. Transcriptomic analysis revealed significantly differential expressions of MKK9, EBF1, and PRB1 genes between QB3 and Ta under both control and infested conditions, with enrichment in the plant MAPK signaling pathway. Following insect herbivory, QB3 upregulated LOX3.1, ACX3, AOS3, PED1, and JMT genes, enriched in α-linolenic acid metabolism. Metabolomic profiling showed significant variations in α-linolenic acid abundance. After ALB feeding, QB3 exhibited a marked increase in α-linolenic acid content compared to Ta, while γ-linolenic acid levels remained unchanged. Both genotypes showed elevated jasmonoyl-isoleucine (JA-Ile) concentrations, with QB3 displaying extremely significant increases versus moderately significant increases in Ta. These results offer insights into poplar tree responses to ALB feeding damage.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147843428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diameter-driven variation in wood CO₂ efflux across the stems and crowns of three temperate broadleaf tree species.","authors":"Kieran Walker, Alexander Shenkin, Yadvinder Malhi","doi":"10.1093/treephys/tpag060","DOIUrl":"https://doi.org/10.1093/treephys/tpag060","url":null,"abstract":"<p><p>A major constraint on modelling woody-tissue CO₂ efflux is the scarcity of datasets that adequately represent its variability and underlying drivers. We intensively sampled CO₂ efflux along the vertical profile of nine temperate broadleaf trees across three species and found substantial longitudinal variation. We partitioned the flux into growth and maintenance-associated components; accordingly we use 'efflux' for measurements and 'respiration' only for the derived components. Expressing efflux by wood volume, surface area, and sapwood volume each offered insight to the underpinning of the flux. However, efflux was most strongly associated with surface area, particularly in medium and large branches, and across both growth and maintenance respiration. In small branches, where sapwood dominates, this surface-area scaling weakens, suggesting maintenance respiration shifts from surface-area to volume-based scaling, while growth respiration remains associated with surface-area. Sapwood depth, tree ring width, and the relative contributions of growth and maintenance respiration explained much of the variation in efflux, though additional biological and physical factors, such as CO₂ diffusion from sap and variation in sapwood parenchyma, likely also contribute. These findings represent an important step towards reducing uncertainty in the spatial scaling of woody-tissue CO₂ efflux by linking within tree variation in respiration to underlying anatomical and growth-related controls.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147843433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonlinear autumn phenology responses to compound drought and heatwave events: results from a manipulative experiment.","authors":"Shuxin Wang, Yufeng Gong, Zhaofei Wu, Yangjing Nie, Nan Wang, Yongshuo H Fu","doi":"10.1093/treephys/tpaf134","DOIUrl":"10.1093/treephys/tpaf134","url":null,"abstract":"<p><p>Climate change-induced shifts in plant phenology have substantially impacted terrestrial ecosystem structure and function. While the effects of drought and heatwaves on leaf senescence have been studied, the response of leaf senescence to compound drought and heatwave events remains poorly understood, especially due to a lack of experimental evidence. In this study, we investigated the responses of leaf senescence to varying durations (13, 28 and 43 days) of compound drought and heatwave stress in saplings of three temperate deciduous tree species. We found that prolonged drought and heatwave conditions delayed leaf senescence by 20.2 days in Koelreuteria paniculata Laxm. and 22.4 days in Hibiscus syriacus L., respectively, potentially as a compensation for stress-induced reductions in growth. However, leaf senescence in the low-tolerance Acer palmatum Thunb. shifted from delayed to advanced, indicating a nonlinear response. Total photosynthesis, relative height increment and basal diameter growth decreased in all three species, with the strongest reductions in A. palmatum, followed by H. syriacus and K. paniculata. Our findings demonstrate delayed effects of environmental stress on leaf senescence and highlight species-specific variation in response to compound drought-heatwave events, providing insights into how plants respond to climate change.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145347483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Organ-specific carbohydrate partitioning strategies in Pinus massoniana seedlings during drought approaching mortality.","authors":"Changchang Shao, Honglang Duan, Xianying Luo, Guijie Ding","doi":"10.1093/treephys/tpag036","DOIUrl":"10.1093/treephys/tpag036","url":null,"abstract":"<p><p>Carbohydrates (e.g., structural carbohydrates and non-structural carbohydrates) can enhance the drought resistance of plants through various mechanisms such as osmotic regulation, cellular protection, xylem reinforcement and energy supply. Although organ-specific carbohydrate allocation under drought has been explored in some species, little is known about the allocation strategies of both structural and nonstructural carbohydrates and their key components across different organs during drought-induced tree mortality. Here, potted Pinus massoniana Lamb. seedlings were treated with 80-day progressive drought stress until mortality, with samples collected every 10 days. The concentrations of total soluble sugars (hereafter referred to as sugars), glucose, sucrose, fructose, starch, structural carbohydrates (cellulose), lignin and key enzymes involved in carbon metabolism were quantified across various organs, including roots, stems (wood and bark) and needles. The results revealed that under progressive drought stress, not only starch but also sugars and their key components (i.e., sucrose, glucose and fructose) were significantly elevated in all plant organs examined, compared with the control conditions. Similarly, the concentration of lignin and cellulose in the roots, as well as lignin in the stems, was markedly elevated compared with the control. These parameters only declined when the seedlings approached mortality (70-80 days). At the end, the needles retained elevated sucrose concentration, while bark and wood exhibited persistently heightened sugar concentration (particularly glucose). Root cellulose concentration and stem lignin concentration remained significantly higher than the control. In summary, different organs of P. massoniana employed distinct carbon investment strategies under extreme drought: needles prioritize osmotic regulatory substances over structural components; stems (e.g., wood and bark) maintain stable structural carbohydrate levels; and roots implement a dual-defense strategy through enhanced physical protection (lignin reinforcement) combined with increased osmotic regulatory substances to strengthen physiological functions.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147504987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tree-ring stable isotopes and growth trajectories reveal early warning signals of drought-induced Scots pine mortality.","authors":"Otmar Urban, Claudia Hartl, Christian Zang, Natálie Pernicová, Josef Čáslavský, Kerstin Treydte, Lea Schneider, Miroslav Trnka, Jan Esper, Ulf Büntgen","doi":"10.1093/treephys/tpag059","DOIUrl":"https://doi.org/10.1093/treephys/tpag059","url":null,"abstract":"<p><p>Summer droughts have affected tree growth in central Europe since at least the 1940s, yet the physiological mechanisms behind why some trees die while others survive remain poorly understood. Here, we present absolutely dated and annually resolved tree-ring width, carbon (δ13C), and oxygen (δ18O) stable isotope chronologies from 18 Scots pines (Pinus sylvestris L.) growing near the species' climatic and edaphic limit in one of Germany's driest regions (Rhine Hesse, near Mainz). Spanning the period 1930-2019, sampled trees were assigned to three post-2018 vitality classes based on crown transparency: vigorous, intermediate, and poor vigour (including dead individuals). We assessed long-term growth and isotopic trajectories in relation to climate variables, with a focus on pan-European summer drought extremes in 1947, 1976, 2003, and 2018. We found that trees with consistently higher growth rates and elevated long-term δ13C values were more susceptible to dieback, whereas surviving trees maintained lower δ13C values. This pattern suggests differences in long-term water-use strategies and/or drought exposure, while also partly reflecting canopy position and light-driven assimilation. In contrast, δ18O values sharply increased during drought events, especially in poor-vigour trees, indicating greater reliance on shallow, evaporatively enriched water sources and heightened hydraulic strain under extreme drought. These isotopic trajectories differentiated vitality classes well before visible canopy decline. Our findings indicate that the 2018 drought was not the sole trigger, but rather a tipping point in a long-term dieback process driven by repeated droughts and heatwaves. Tree-ring stable isotopes, particularly when interpreted alongside growth trajectories, provide valuable early-warning signals of physiological stress and drought vulnerability. Since trees with conservative growth strategies were more resilient, long-term physiological stability, rather than maximum productivity, may enhance forest resilience under an increasingly warm, dry, and variable future climate.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147782278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The photosynthetic rate dominates the seasonal variation of tree intrinsic water-use efficiency in humid East Asian Monsoon region.","authors":"Xinyu He, Yao Li, Ru Huang, Wenling An, Kerstin Treydte, Qingyu Zhao, Junbo Ren, Sainan Liu, Chenxi Xu","doi":"10.1093/treephys/tpag061","DOIUrl":"https://doi.org/10.1093/treephys/tpag061","url":null,"abstract":"<p><p>Intrinsic water-use efficiency (iWUE) in trees, defined as the ratio of photosynthetic rate (A) to stomatal conductance (gs), is a key indicator characterizing the carbon-water balance in trees. Previous studies have suggested that seasonal variation in iWUE is primarily controlled by gs in arid regions; however, the main driving factors in humid regions remain unclear. Therefore, this study utilized 8 years of high-resolution tree-ring δ13C and δ18O data from P. massoniana (coniferous) and S. tzumu (broadleaf) in the humid East Asian monsoon region to reconstruct the seasonal dynamics of iWUE. We estimated iWUE based on δ13C and derived the leaf water δ18O enrichment (Δ18Olw) from δ18O to represent gs, thereby distinguishing the relative contributions of A and gs to variations in iWUE. Both species exhibited synchronous seasonal iWUE patterns: decreasing from spring to summer before autumn recovery. Dual-isotope analysis revealed that iWUE seasonal variations were primarily driven by fluctuations in A, contrasting with gs-dominated mechanisms in arid regions. Summer iWUE declines resulted from reduced A, constrained by relatively low CO2 and high temperatures. This study reveals an A-dominated regulatory mechanism of iWUE in humid regions, providing a theoretical basis for more accurate predictions of forest carbon-water coupling under varying moisture conditions.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147782264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"FLIM-Based Detection of Early Wound-Response Signatures Suggesting Rooting Hotspots in Argania spinosa.","authors":"Alexander Klaus, Sela Yechezkel, Eduard Belausov, Einat Sadot","doi":"10.1093/treephys/tpag043","DOIUrl":"https://doi.org/10.1093/treephys/tpag043","url":null,"abstract":"<p><p>Root regeneration from stems requires cells to reprogram their developmental trajectories. This reprogramming becomes possible when multiple factors converge at specific sites, ultimately giving rise to adventitious roots in what often appears to be a random pattern. Here, we asked whether such rooting \"hotspots\" could be detected by fluorescence-lifetime imaging microscopy (FLIM). Using stem cuttings from a difficult to root Argania spinosa clone, we examined wounded tissues by microscopy. Upon 440 nm illumination, discrete and asymmetric regions emerged in which fluorescence events with lifetimes below 2 ns increased within 3 hours. Further, we show that similar lifetime signal appeared both around newly initiating root primordia and along what seemed to be their outward pathway through the stem tissues. These observations suggest that early, localized modifications in cell wall composition occur prior to visible root formation and may mark sites with the competence to initiate adventitious roots.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147782247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Similar water uptake depths in lianas and trees, but divergent functional trait coordination across organs in a seasonally dry tropical forest in Cambodia.","authors":"Katsuura Hiiragi, Thav Sopheak, Chea Sophors, Hiroki Hosokawa, Naoko Matsuo, Shuichiro Tagane, Michiko Nakagawa","doi":"10.1093/treephys/tpag057","DOIUrl":"https://doi.org/10.1093/treephys/tpag057","url":null,"abstract":"<p><p>Although previous studies have suggested that lianas exhibit superior growth compared to trees during dry seasons, their strategies for acquiring water remain poorly understood. This study investigated the water uptake depth and above-ground functional traits of 10 liana species and 11 tree species coexisting in a seasonally dry tropical evergreen forest in Cambodia. Using stable oxygen isotopes, we estimated dry-season water uptake depths and compared five functional traits, including specific leaf area (SLA), leaf nitrogen (LNC) and phosphorus content (LPC), stable carbon isotope ratio (δ13C) of leaves, and wood density (WD). Both lianas and trees absorbed water mainly from middle to deep soil layers, with no significant difference in water uptake depth. We found substantial variation in water uptake depth even within the same life-form, with some species relying on shallow soil water and others accessing much deeper sources, indicating diverse water acquisition strategies during the dry season. With slightly higher SLA and lower WD, lianas showed a relatively acquisitive carbon- and nutrient-use strategy compared to trees; however, there was no significant difference in water use efficiency, as represented by leaf δ13C. Patterns of trait coordination among multiple organs differed between lianas and trees. In lianas, deeper water uptake was positively correlated with less negative leaf δ13C, whereas in trees this relationship was negative as well as weak. This divergence highlights different functional strategies even under similar environmental pressures. Our findings underscore the fact that lianas did not consistently use deeper water or show higher water use efficiency than trees in this ecosystem. Instead, trait variations and the coordination between above- and below-ground traits may help explain the success of lianas in seasonally dry environments.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147782318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Mechanistic Framework for Order-Specific Fine-Root Turnover and Carbon Dynamics: Application to the Duke Forest FACE Experiment.","authors":"Daniel Poll, Luke Vaughan, Seth Pritchard, Katilyn V Beidler, Benton Taylor, Allan Strand","doi":"10.1093/treephys/tpag040","DOIUrl":"https://doi.org/10.1093/treephys/tpag040","url":null,"abstract":"<p><p>Accurate quantification of fine-root turnover, a pathway representing a large and uncertain flux of carbon into soils, is critical for improving terrestrial ecosystem models. Efforts to model this carbon flux directly have relied on tracing stable carbon isotopes through root systems, and these studies reveal complex dynamics in sampled fine-roots, best described to date by two-rate models. The rates derived from these models have been traditionally interpreted either as two distinct turnover rates (fast and slow), or as movement through two distinct biochemical pools (labile, recently fixed carbon, and recalcitrant carbon consisting of complex polymers like lignin). However, a competing, mechanistic explanation exists, the observed two-rate dynamics may reflect the demography of the root system, where roots of different functional classes (e.g., defined by root order) inherently possess differential lifespans and turnover rates. Here we introduce a new model, the Demographic Carbon Distribution Model (DCDM) that models both the carbon flux into root systems and the demography of fine roots. We then fit each of these models to $delta ^{13}$C values obtained from loblolly (Pinus taeda) fine roots. The DCDM model predicts that root turnover is substantially faster than has been previously reported. Pairing this model with data on fine roots assayed by root order, we were able to obtain estimates of fine-root turnover for different functional groups of roots. Furthermore, sampling individual roots highlights the importance of variation in root turnover estimates, indicating that mean behavior alone is insufficient to capture complex root dynamics. Because terrestrial carbon models depend on estimates of root turnover, we demonstrate how the estimates obtained here could impact predictions from ecosystem models.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147782170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}