Tree physiology最新文献

{"title":"Effects of drought on carbon-nitrogen dynamics in root exudates of Qinghai spruce.","authors":"Weibin Li, Hongxia Zhang, Yingyi Pu, Fan Li","doi":"10.1093/treephys/tpaf085","DOIUrl":"10.1093/treephys/tpaf085","url":null,"abstract":"<p><p>Root exudates play a critical role in plant adaptation and the regulation of soil carbon and nutrient cycling, especially under climate change conditions. Despite their importance, the dynamics of root exudation under drought, particularly during drought-induced tree mortality, remain poorly understood. Here, we investigate how drought affects root exudation dynamics, root morphology traits and non-structural carbohydrate (NSC) concentrations in Qinghai spruce (Picea crassifolia Kom.) seedlings across the progression of drought-induced mortality. We conducted a two-stage drought manipulation experiment, beginning with moderate drought (50% irrigation reduction) followed by complete water cessation to induce lethal drought conditions. Our results reveal that drought significantly decreased the exudation rate of total organic carbon (C), while nitrogen (N) exudation rate remained unaffected, resulting in a lower C:N ratio in root exudates, indicative of a higher proportion of N-rich compounds. In addition, drought induced a shift in root morphological traits toward a more competitive strategy, marked by increased specific root length (SRL), specific root area (SRA) and branch intensity, and a reduction in root diameter (RD), root tissue density and root NSC concentrations. Notably, root exudation rates were negatively correlated with competitive root traits (higher SRL, SRA and branch intensity) and positively correlated with conservative traits (larger RD and root tissue density), suggesting that root exudation serves a more conservative function under drought conditions, prioritizing carbon storage and morphological adaptations over exudation. These findings provide valuable insights into the adaptive mechanisms of trees under drought stress, with implications for nutrient cycling, forest resilience and ecosystem productivity in water-limited environments.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144675739","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":"Stem water monitoring reveals an association with rainfall and leaf flush timing in a tropical dry forest of Zambia.","authors":"Emmanuel N Chidumayo","doi":"10.1093/treephys/tpaf084","DOIUrl":"10.1093/treephys/tpaf084","url":null,"abstract":"<p><p>Tropical dry forests (TDFs) occur in tropical regions that experience alternating dry and wet seasons, which might lead to stem water status being determined by seasonality in rainfall and leaf phenology. However, these relations may also vary between canopy and understorey trees. I tested whether relative and specific stem water content (SWC) are associated with climate factors, leaf phenology and rooting depths in 10 shrub and tree species in a TDF in Zambia. In addition, it was tested whether the pre-rain leaf flush of TDFs is sustained by stem water reserves and/or uptake of water from deep soil. At the end of the wet season, large trees contained over 65 L of water in aboveground biomass while small trees and shrubs contained <42 L, which were assumed to represent peak biomass stored water. Stem rehydration in large trees started during the hot-dry season, 2-3 months before the onset of the rainy season. In contrast, stem rehydration in small trees and shrubs only occurred after sufficient rainfall in the rainy season. Only large trees exhibited pre-rains leaf flush while small trees and shrubs did not, perhaps due to low biomass water reserves. The SWC was positively affected by cumulative rainfall prior to sampling date and leaf phenological status. High rainfall during 28 days preceding twig sample collection was associated with high SWC. The highest and lowest SWC values were recorded during the green-leaf and leafless phases, respectively. The association between SWC and taproot depth was negative. Apparently, deep-soil lateral roots of large trees play a more important role in sustaining pre-rains leaf display than taproots. These findings are useful in the assessment of soil-plant-atmosphere water transference in TDFs of East and southern Africa.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144660364","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":"Cell wall thickness constrains photosynthesis of coexisting species in a subtropical plantation by reducing mesophyll conductance and maximum carboxylation rate.","authors":"Minru Liao, Jing Wang, Xuefa Wen","doi":"10.1093/treephys/tpaf078","DOIUrl":"10.1093/treephys/tpaf078","url":null,"abstract":"<p><p>The interspecific variation in the net photosynthetic rate (Anet) reflects coordination and trade-offs between biophysical and biochemical processes, yet the underlying morphophysiological mechanisms remain poorly understood. To address this, we quantified photosynthetic parameters as well as morphological, anatomical and nutrient traits of 12 coexisting needle and broadleaf species within a subtropical coniferous plantation of the East Asian monsoon region. Across species, Anet is primarily constrained by stomatal conductance (gs), secondarily by maximum carboxylation rate (Vcmax) and minimally by mesophyll conductance (gm). A negative correlation between gs/Anet and gm/Anet suggests that increases in gm partially compensate for stomatal limitations on Anet, while the negative correlation between gt/Anet (gt, total conductance) and Vcmax/Anet reflects CO2 supply-demand trade-off during photosynthesis. Variation in gm reflects the coordination between cell wall thickness (TCW) and the chloroplast surface area exposed to intercellular air spaces (Sc/S). Variation in Vcmax is negatively related to TCW, rather than to leaf nitrogen and phosphorus per unit area. Structural equation modeling further reveals that TCW indirectly regulates Anet through both Vcmax and gm, with its limiting effect on Vcmax being slightly stronger than on gm. Needle species exhibit gs and Vcmax comparable to those of broadleaf species; however, their lower gm results in a significantly reduced Anet. This reduction is attributed to greater TCW and lower Sc/S. Additionally, the higher TCW in needle species may lead to increased allocation of leaf nitrogen to non-photosynthetic tissues, as their significantly higher leaf nitrogen content compared with broadleaf species is not accompanied by a corresponding increase in Vcmax. Variation in Vcmax is driven by TCW rather than by leaf nutrient, underscoring the necessity of incorporating leaf anatomical traits into mechanistic and predictive models. Moreover, as water and nitrogen limitations increase during forest succession, needle species in subtropical plantations-characterized by low gm and high TCW-are likely to be replaced by broadleaf species.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12363393/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144584967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ontogenetic shift in biomass allocation and functional traits of leaves and seeds in a resprouting aridland shrub.","authors":"Guang-Qian Yao, Yu-Na Duan, Shun-Ping Han, Yan-Ru Li, Yi-Chen Li, Shi-Hua Qi, Feng-Ping Li, Min-Hui Bi, Xiang-Wen Fang","doi":"10.1093/treephys/tpaf086","DOIUrl":"10.1093/treephys/tpaf086","url":null,"abstract":"<p><p>Ontogeny-driven variation in plant functional traits is considered the core component of a plant's life-history strategy. However, how vegetative and reproductive traits covary to mediate growth and reproduction throughout the life history of resprouts is largely unknown. Here, the leaf and seed biomass allocation (SBA), nutrient contents and morphological and physiological traits of leaves and seeds were investigated during different life history stages of Caragana korshinskii Kom resprouts aged 1-13 years in a common garden. The findings indicated that with increasing age, leaf traits shifted from an acquisitive strategy-characterized by high photosynthesis (An), stomatal conductance (gs), leaf nitrogen content (LNC) and leaf phosphorus content (LPC), along with low leaf mass per area (LMA) and water-use efficiency (WUE)-to a conservative strategy characterized by low An, gs, LNC, LPC, high LMA and WUE, in combination with changes in leaf biomass allocation (LBA). Most notably, seed traits shifted from a K-strategy-characterized by high seed mass (SM), seed nitrogen content (SNC), seed phosphorus content (SPC) and seed germination rate (SGR), but low seed number (SN)-to an r-strategy with opposite traits, reflecting a trade-off with SBA. These ontogeny-driven strategies shift from an acquisitive strategy and K-strategy that favors faster growth and a quality-focused reproductive advantage in younger resprouts to a conservative strategy and r-strategy that improves vegetative adaptability and reproductive stability in older resprouts. Our results highlight that ontogeny-driven transitions in life history strategies and biomass allocation patterns jointly mediate vegetative and reproductive strategies in resprouts, providing new insights for understanding the dynamic balance between the growth and reproduction of resprouts.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144699645","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":"Leaf transpiration decreases similarly among five pine species as height increases over stand development.","authors":"Chainey A Boroski, Jean-Christophe Domec, Christopher Maier, Sari Palmroth, Yi Wang, Ram Oren","doi":"10.1093/treephys/tpaf093","DOIUrl":"https://doi.org/10.1093/treephys/tpaf093","url":null,"abstract":"<p><p>With increasing tree height, leaf transpiration (EL) is increasingly restricted by path-length resistance and gravity's discount to the driving force of xylem water flow. The effect of height on leaf transpiration is nearly always assessed using chronosequence data; however, in this long-term, dynamic study, we assessed increasing height's effects on EL using continuous monitoring of sap-flux for five Pinus species growing in a common-garden and experiencing a wide range of environmental conditions. We assessed how three drivers of EL-path-length (h), water-potential gradient (ΔΨ), and sapwood-to-leaf area ratio (AS:AL)-affect transpiration of the five Pinus species ranging five-fold in needle length by performing gas-exchange and water potential measurements, and monitoring tree biometrics, sap-flux, and soil and atmospheric conditions over five years at the Duke Forest, NC. With our methods controlling for all but the effect of tree hydraulics on transpiration, we found that EL, derived early in the study based on gas-exchange and later based on sap-flux measurements, were similar among species under both wet and dry soil moisture conditions. When soil moisture was not limiting, ΔΨ decreased across species with increasing needle length while whole-plant conductance (kplant) increased, leading to similar EL among species. Under soil drought, the trends with needle length of both variables became weaker as shorter-needle species showed a greater decrease in ΔΨ, while longer-needle species had a greater decline in kplant, again resulting in similar EL among species. Increasing h over time reduced EL similarly in all species, in part owing to similar annual minima of AS:AL among species and its invariance over a four-fold range in h. Controlling for non-hydraulic sources of variation showed that EL decreased with h similarly in five Pinus spp. of a wide range in leaf and crown characteristics.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144733393","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":"An updated sulfate transporter phylogeny uncovers a perennial-specific subgroup associated with lignification.","authors":"Samantha M Surber, Chen Hsieh, Lan Na, Scott A Harding, Chung-Jui Tsai","doi":"10.1093/treephys/tpaf080","DOIUrl":"https://doi.org/10.1093/treephys/tpaf080","url":null,"abstract":"<p><p>Sulfate-proton co-transporters (SULTRs) mediate sulfate uptake, transport, storage, and assimilation in plants. The SULTR family has historically been classified into four groups (SULTR1-SULTR4), with well-characterized roles for SULTR groups 1, 2, and 4. However, the functions of the large and diverse SULTR3 group remain poorly understood. Here, we present an updated phylogenetic analysis of SULTRs across angiosperms, including multiple early-divergent lineages. Our results suggest that the enigmatic SULTR3 group comprises four distinct subfamilies that predate the emergence of angiosperms, providing a basis for reclassifying the SULTR family into seven subfamilies. This expanded classification is supported by subfamily-specific gene structures and amino acid substitutions in the substrate-binding pocket. Structural modeling identified three serine residues uniquely lining the substrate-binding pocket of SULTR3.4, enabling three hydrogen bonds with the phosphate ion. The data support the proposed neofunctionalization of this subfamily for phosphate allocation within vascular tissues. Transcriptome analysis of Populus tremula × alba revealed divergent tissue expression preferences among SULTR subfamilies and between genome duplicates. We observed partitioned expression in vascular tissues among the four SULTR3 subfamilies, with PtaSULTR3.4a and PtaSULTR3.2a preferentially expressed in primary and secondary xylem, respectively. Gene coexpression analysis revealed coordinated expression of PtaSULTR3.4a with genes involved in phosphate starvation responses and nutrient transport, consistent with a potential role in phosphate homeostasis. In contrast, PtaSULTR3.2a was strongly coexpressed with lignification and one-carbon metabolism genes and their upstream transcription regulators. PtaSULTR3.2a belongs to a eudicot-specific branch of the SULTR3.1 subfamily found only in perennial species, suggesting a specialized role in lignifying tissues. Together, our findings provide a refined phylogenetic framework for the SULTR family and suggest that the expanded SULTR3 subfamilies have undergone neofunctionalization during the evolution of vascular and perennial plants.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144609694","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":"Populus VariantDB v3.2 facilitates CRISPR and Functional Genomics Research.","authors":"Ran Zhou, Sakshi R Seth, Jacob Reeves, Andrew H Burns, Chen Hsieh, Thomas W Horn, Liang-Jiao Xue, Chung-Jui Tsai","doi":"10.1093/treephys/tpaf081","DOIUrl":"https://doi.org/10.1093/treephys/tpaf081","url":null,"abstract":"<p><p>The success of CRISPR genome editing studies depends critically on the precision of guide RNA (gRNA) design. Sequence polymorphisms in outcrossing tree species pose design hazards that can render CRISPR genome editing ineffective. Despite recent advances in tree genome sequencing with haplotype resolution, sequence polymorphism information remains largely inaccessible to various functional genomics research efforts. The Populus VariantDB v3.2 addresses these challenges by providing a user-friendly search engine to query sequence polymorphisms of heterozygous genomes. The database accepts short sequences, such as gRNAs and primers, as input for searching against multiple poplar genomes, including hybrids, with customizable parameters. We provide examples to showcase the utilities of VariantDB in improving the precision of gRNA or primer design. The platform-agnostic nature of the probe search design makes Populus VariantDB v3.2 a versatile tool for the rapidly evolving CRISPR field and other sequence-sensitive functional genomics applications. The database schema is expandable and can accommodate additional tree genomes to broaden its user base.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144609695","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":"An ectopic xylem cell induction system to unravel the molecular mechanisms of secondary cell wall formation in the coniferous tree, Cryptomeria japonica.","authors":"Ryosuke Sato, Soichiro Nagano, Yoshihiko Nanasato, Ken-Ichi Konagaya, Toru Taniguchi, Naoki Takata","doi":"10.1093/treephys/tpaf077","DOIUrl":"https://doi.org/10.1093/treephys/tpaf077","url":null,"abstract":"<p><p>Wood is a vital renewable resource for energy, construction, and pulp production. Understanding the molecular mechanisms governing wood formation is therefore crucial for both basic research and applied forestry. The xylem, a major component of wood, plays a crucial role in water transport and mechanical support in trees, requiring a robust secondary cell wall to endure water pressure and support the tree's weight. Gaining deeper insight into xylem cell differentiation is therefore important for both fundamental biological research and industrial applications. In vitro systems for inducing xylem cell differentiation have been developed in various plants, including Arabidopsis thaliana where key regulators such as the VASCULAR-RELATED NAC DOMAIN (VND) transcription factor (TF) have been identified. However, research on coniferous trees remain limited, with most studies focusing on morphological aspects with limited molecular analysis. In this study, we developed an efficient xylem cell induction system for Cryptomeria japonica using bikinin, a glycogen synthase kinase 3 (GSK3) inhibitor, in combination with cytokinin, auxin, and brassinolide. This system induced ectopic xylem cells in the somatic embryos and cotyledons of seedlings within 2 weeks, significantly faster than methods reported in previous studies. We conducted a comprehensive time-series transcriptome analysis during xylem cell induction in somatic embryos and identified genes expressed throughout the course of xylem cell formation. Our analysis revealed a sequential upregulation of key regulatory genes, including VND- and MYB-like TFs, followed by genes involved in cellulose biosynthesis, suggesting their role in tracheary element formation. These findings suggest that the molecular mechanisms regulating xylem cell formation in the gymnosperm C. japonica are fundamentally conserved with the NAC-MYB transcriptional network known in angiosperms.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144584966","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":"Uncovering the mechanisms of heartwood formation and wood resistance to fungal degradation in the tropical Lauraceae tree Sextonia rubra (Mez.) van der Werff.","authors":"Marceau Levasseur, Ambre Senelis, Flavien Zannini, Muriel Barbier, Elsa Van Elslande, Nadine Amusant, Yannick Estevez, Véronique Eparvier, Éric Gelhaye, David Touboul, Emeline Houël","doi":"10.1093/treephys/tpaf079","DOIUrl":"https://doi.org/10.1093/treephys/tpaf079","url":null,"abstract":"<p><p>Heartwood formation is a complex process that contributes to ensuring the integrity of trunks and the longevity of trees. We examined this mechanism in the tropical angiosperm Sextonia rubra in relation to the spatial distribution of specialised metabolites and their functional role at the scale of a mature individual. Heartwood formation was analysed starting from the examination of one of its properties, namely the decay resistance, of the different S. rubra wood tissues (sapwood, heartwood, and pith) using soil bed tests. Annotation and identification of the metabolites present in ethyl acetate extracts were carried out by reverse-phase liquid chromatography coupled to a tandem mass spectrometer (RPLC-ESI-MS/MS) and molecular networks. Following the application of supervised statistical analyses and the use of Glutathione S-transferases enzymatic assays, the specialised metabolites of interest were quantified radially and longitudinally in the different tissues using RPLC-ESI-HRMS system. Heartwood and pith were shown to resist degradation after a ten-months exposure to forest soil, with no effect of the heartwood cambial age. Molecular diversity was specific to each tissue type, with flavonoids and butanolides detected in bark and sapwood, while alkaloids and butyrolactones were identified in heartwood and pith. Supervised analyses and enzyme assays suggested that alkaloids and butyrolactones play a role in the resistance of internal tissues to degradation. Butyrolactone concentrations peaked in the middle heartwood but remained homogeneous longitudinally, while alkaloid concentrations were uniform longitudinally and radially in the heartwood. In conclusion, the resistance of heartwood and pith to fungal degradation was correlated with the accumulation of lactones and alkaloids. While butanolide precursors of butyrolactones have been detected in the sapwood, alkaloids appear to be directly biosynthesised in the heartwood. This suggests that the biosynthesis and accumulation of specialised metabolites during heartwood formation is specific to each molecular family.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144584968","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":"PbHDZ35, an HD-ZIP transcription factor, regulates the trade-off between growth and drought stress in Phoebe bournei.","authors":"Yan Liu, Xiao Li, Mingyang Ni, Yuting Zhang, Wenjun Ma, Yandong Song, Zaikang Tong, Junhong Zhang","doi":"10.1093/treephys/tpaf068","DOIUrl":"10.1093/treephys/tpaf068","url":null,"abstract":"<p><p>Phoebe bournei (Hemsl.) Yang, a valuable afforestation species in subtropical China, is highly sensitive to water availability, thus the growth and distribution significantly impacted by recurrent extreme drought events. Previous studies showed that homeodomain-leucine zipper (HD-ZIP) transcription factors play crucial roles in plant development and abiotic stress responses. However, there has been no thorough investigation of the HD-ZIP gene family in P. bournei, and their regulatory roles under drought stress remain unknown. In the present study, we identified and characterized 42 HD-ZIP genes in P. bournei. Weighted gene co-expression network analysis (WGCNA) of PEG-induced transcriptomic data revealed an ABA-associated gene, PbHDZ35 (homologous to AtHB7/12), which displayed strong sensitivity to Polyethylene glycol (PEG) treatment, abscisic acid (ABA) and natural drought stress. Interestingly, there are two opposite phenotypes of PbHDZ35-overexpressing plants between normal and drought condition, showing enhanced growth in transgenic plants under normal condition, but reduced drought tolerance. To illuminate the regulatory mechanism of PbHDZ35, a DAP-seq was conducted to identify the potential downstream genes of PbHDZ35. Based on the quantitative results from transient transformation in P. bournei leaves and stable transformation in hairy roots, PbHDZ35 was identified as a potential regulator of the ABA receptor PbPYL5 and the auxin response factor PbARF8. Yeast one-hybrid and dual-luciferase assays confirmed the involvement of PbHDZ35 in both ABA feedback regulation and auxin signaling pathways. Our findings demonstrate that PbHDZ35 orchestrates the trade-off between growth and drought tolerance in P. bournei by dual regulation of ABA signaling (via PbPYL5) and auxin responses (via PbARF8), highlighting its pivotal role in balancing stress adaptation with developmental plasticity under water-limited environments.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144200097","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}