Tree physiology最新文献

{"title":"Leaf physiological and endophytic microbial community characteristics and interactions of different scions grafted onto Malus sieversii.","authors":"Huanhuan Zhang, Dongdong Yao, Hossam S M Ali, Guangxin Zhang, Xujiao Li, Jingshan Xi, Yingchi Liang, Li Shao, Fengyun Zhao, Songlin Yu, Kun Yu","doi":"10.1093/treephys/tpaf042","DOIUrl":"10.1093/treephys/tpaf042","url":null,"abstract":"<p><p>Endophytic microbial communities in scion leaves substantially impact the growth efficiency of apple trees (Malus × domestica Borkh.); however, the underlying mechanisms remain underexplored. Herein, we grafted three varieties-Malus sieversii, Hanfu and Fuji-onto M. sieversii (Ledeb.) M. Roem rootstocks and employed high-throughput sequencing technology to investigate how physiological traits of scion leaves influence endophytic microbiota and apple tree growth. Compared with the M. sieversii scion, the aboveground (+49.28%) and root (+62.77%) biomass of juvenile trees grafted with the Hanfu scion significantly increased, with the net photosynthetic rate and stomatal conductance rising by 20.40% and 42.26%, respectively. Additionally, the leaves of the Hanfu scion exhibited a significant increase in sucrose synthase activity and carbon accumulation (CA) compared with the M. sieversii and Fuji scions, while the carbon content and carbon-to-nitrogen ratio (C/N) significantly decreased. Furthermore, through 16S rDNA and internal transcribed spacer high-throughput sequencing, we found that the diversity and abundance of endophytic bacteria and fungi in the leaves of the Hanfu scion were higher than in the M. sieversii and Fuji scions. Hanfu scion leaves were predominantly enriched with the phyla Firmicutes and Ascomycota and the genus Salinicoccus. A close association was observed between leaf endophytic bacterial and fungal communities and physiological traits, with particularly significant correlations in the fungal communities. Parameters such as leaf intercellular carbon dioxide concentration, chlorophyll b content, C/N and CA were implicated in enriching dominant endophytic microbial phyla and genera. Through partial least squares structural equation models, we confirmed that leaf photosynthetic properties and carbon and nitrogen metabolism significantly affect leaf carbon and nitrogen accumulation through the regulation of endophytic fungal diversity, thereby affecting apple tree growth. In conclusion, the interaction between leaf physiological properties of different scion varieties and the diversity and composition of endophytic microbial communities influences apple tree growth.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143796442","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":"Analysis of SRO gene family in Nitraria sibirica Pall. and the function of NsSRO1a in improving plant drought tolerance.","authors":"Rongfeng Duan, Hongxia Zhang, Yanqiu Zhao, Huilong Zhang, Rong Li, Xihong Wan, Shuaihui Zhang, Pengyu Ying, Huaxin Zhang, Xiuyan Yang","doi":"10.1093/treephys/tpaf050","DOIUrl":"10.1093/treephys/tpaf050","url":null,"abstract":"<p><p>The SIMILAR TO RCD ONE (SRO) protein family is an important regulatory protein in plants and plays a key role in growth and development and adaptation to environmental stress. Nitraria sibirica Pall. grows in extreme environments and has significant stress resistance, so it is regarded as an ideal material for mining stress resistance genes. However, the members and functions of the SRO gene family in N. sibirica have not been studied. In this study, three SRO genes were identified in N. sibirica, named NsSRO1a, NsSRO1b and NsSRO2. Phylogenetic analysis indicated that these genes could be divided into three groups (Group I, Group II and Group III) and showed high conservation in gene structure and conserved motifs. Promoter cis-acting element analysis revealed that the promoter regions of these genes contained a variety of stress response elements. After treatment with mannitol, it was found that the expression of NsSRO1a in N. sibirica was up-regulated, suggesting that it may be a key functional gene for drought resistance. NsSRO1a was overexpressed in poplar, a woody plant model, and overexpressed plants were verified. Overexpression of NsSRO1a significantly reduced the accumulation of reactive oxygen species (ROS) and cell damage by regulating stomatal aperture and increasing chlorophyll content, proline (Pro) content, antioxidant enzyme activity and related gene expression, thus significantly improving the drought resistance of transgenic plants. These results showed that NsSRO1a enhances the drought resistance of plants by regulating ROS metabolism under drought stress, which provides an important reference for improving plant stress resistance.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144015940","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":"Suppressed water availability in winter buds delays the bud burst of broad-leaved trees in a heavy snow forest.","authors":"Shin Shoji, Kenichi Yoshimura","doi":"10.1093/treephys/tpaf048","DOIUrl":"10.1093/treephys/tpaf048","url":null,"abstract":"<p><p>Early snowmelt is known to accelerate budburst. Budburst and leaf expansion require water absorption, and current-year vessels, which function as water pathways, begin to mature in early spring. However, whether the limitation of xylem reactivation by snow affects budburst and leaf expansion remains unclear. The response of winter buds to seasonal changes in both air and soil temperatures under snow cover, as buds transition from dormancy to budburst, requires clarification. The aim of this study was to clarify how snow affects budburst and leaf expansion. We focused on whether limitations in xylem reactivation and the restrictions on water use in stems, twigs and buds due to snow affect budburst. We established two distinct sites with different snow depths in Japan. From winter to summer, we observed leaf phenology, current-year xylem reactivation and measured bud-water content in response to ambient temperatures in canopy trees of Quercus crispula and Fagus crenata. Water absorption in winter buds towards bud burst may not be suppressed by the limitation of xylem reactivation, because the maturation of current-year vessels is likely important for water use for new leaf expansion after budburst in both tree species and sites. We suggest that current-year vessels matured for water use for new leaf expansion and transpiration because vessel maturation timing was linked to the leaf growth period during early spring. From the results of water absorption rate in winter buds towards budburst, we elucidated that budburst timing was delayed because winter buds require substantial time to absorb water in a forest with a deep snow cover during spring than in a forest with less snow cover. This study concluded that soil temperature influences water absorption in winter buds towards budburst.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144055282","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":"Red maple tree root water uptake depths are influenced by neighboring tree species composition.","authors":"Matthew Sobota, Kevin Li, James Knighton","doi":"10.1093/treephys/tpaf049","DOIUrl":"10.1093/treephys/tpaf049","url":null,"abstract":"<p><p>Understanding how mixed-species forests uptake subsurface water sources is critical to projecting future forest water use and stress. Variation in root water uptake (RWU) depths and volumes is common among trees but it is unclear how it is affected by species identity, local water availability or neighboring tree species compositions. We evaluated the hypothesis that RWU depths and the age of water (i.e., time since water entered soils as precipitation) taken up by red maples (Acer rubrum) varied significantly between two forested plots, both containing red maples, similar soils, topography and hydrologic conditions, but having different neighboring tree species. We measured soil moisture contents as well as stable isotopes (δ2H, δ18O) in plant xylem water and soil moisture across two years. These data were used to calibrate process-based stand-level ecohydrological models for each plot to estimate species-level RWU depths. Model calibration suggested significant differences in red maple tree RWU depths, transpiration rates and the ages of water taken up by maples across the two stands. Maple trees growing with ash and white spruce relied on significantly deeper and older water from the soil profile than maple trees growing with birch and oak. The drought risk profile experienced by maple trees differed between the plots as demonstrated by strong correlations between precipitation and model simulated transpiration on a weekly time scale for maples taking up shallow soil moisture and a monthly time scale for maples reliant on deeper soil moisture. These findings carry significant implications for our understanding of water competition in mixed-species forests and for the representation of forest rooting strategies in hydrologic and earth systems models.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12100743/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144014671","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":"Moderately and severely defoliated Quercus ilex L. trees exhibit hydraulic dysfunction and carbon depletion: physiological implications for Mediterranean forest monitoring.","authors":"Francesca Alderotti, Filippo Bussotti, Antonella Gori, Francesco Ferrini, Mauro Centritto, Martina Pollastrini, Cassandra Detti, Ermes Lo Piccolo, Diana Vanacore, Cecilia Brunetti","doi":"10.1093/treephys/tpaf033","DOIUrl":"10.1093/treephys/tpaf033","url":null,"abstract":"<p><p>The increase in drought occurrence and intensity is contributing to rising rates of Quercus ilex L. (holm oak) mortality. Key physiological traits involved include hydraulic dysfunction and carbohydrate depletion. This study monitored xylem embolism and non-structural carbohydrates (NSCs) availability in adult holm oaks under harsh environmental conditions to identify thresholds of physiological impairment associated with increased mortality risk. Seasonal measurements of percentage loss of hydraulic conductivity (PLC), xylem water potential (Ψx) and NSCs were conducted over two years in trees categorized by defoliation severity: non-defoliated (CL1), moderately defoliated (CL2) and severely defoliated (CL3). Increased crown defoliation correlated with higher PLC and reduced NSC availability, with significant differences observed primarily in summer and autumn. Xylem embolism and carbon uptake (inferred from NSC content) showed asynchronous patterns across seasons. In summer and autumn, CL2 and CL3 trees experienced 40-50% PLC, coinciding with reduced carbon uptake. Over the two years, the physiology of CL2 trees deteriorated to a similar level to that of CL3 trees. PLC remained stable in non-defoliated CL1 trees, while decreased seasonally in CL2 and CL3 trees during winter and spring. Interestingly, CL2 and CL3 trees showed delayed starch reserve recovery, which occurred in winter rather than autumn, as observed in CL1 trees. This delayed recovery suggests the absence of autumn NSC replenishment as a potential early warning sign of physiological impairment leading to holm oak decline. Our findings suggest that moderate crown defoliation may conceal severe physiological damage, leading to PLC, Ψx and NSC values comparable to those of severely defoliated trees in later stages.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143721604","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":"Increasing air-filled vessels has little influence on vulnerability to drought-induced embolism in two species with long maximum xylem vessel length but low vessel connectivity.","authors":"Chris M Smith-Martin, Kate M Johnson, Shelley Urquhart, Madeline R Carins-Murphy, Celia M Rodriguez-Dominguez, Christopher Lucani, Déborah Corso, Brendan Choat, Alice Gauthey, Laura Victoria Perez-Martinez, Scott A M McAdam, Leland K Werden, Timothy J Brodribb","doi":"10.1093/treephys/tpaf041","DOIUrl":"10.1093/treephys/tpaf041","url":null,"abstract":"<p><p>Perennial woody plants accumulate native xylem embolisms over time. However, whether this makes the water transport system more vulnerable to drought-induced dysfunction as the percentage of gas-filled vessels increases is unclear. We tested whether increasing the proportion of open (air-filled) vessels changes the overall embolism vulnerability in stems of angiosperm species with long maximum vessel lengths but relatively low vessel connectivity. Using optical vulnerability curves, we measured xylem vulnerability of 57 branches ranging in length from ~ 10 to over 300 cm, from two adult trees (Acacia mearnsii De Wild. and Eucalyptus globulus Labill.) known to have long maximum vessel length (>75 cm) but low vessel connectivity. The fraction of open vessels at different branch lengths was estimated by staining open vessels under suction and with X-ray micro-computed tomography (μCT). To relate this to native field conditions, the percentage of pre-existing native embolisms was measured with μCT on a different set of branches. Our results show that even when a large proportion (> 25%) of open (air-filled) vessels are present, the xylem-embolism thresholds (water potential at 12% (P12), 50% (P50) and 88% (P88) embolized xylem area) resemble those of branches with no open vessels. Scanning of native embolism with μCT revealed 10% (E. globulus) and 20% (A. mearnsii) native embolism under natural conditions. We conclude that even when approximately one-quarter of vessels are air-filled, there is no discernable effect on the overall xylem vulnerability of stem segments with long vessels and low vessel connectivity. Xylem vulnerability to embolism among all the branches measured from each of the two trees was relatively homogeneous with a ~10-20% variation. Our findings also suggest that the presence of pre-existing native embolisms, at the percentages observed in the field (<25%), would not increase vulnerability to xylem embolism in these species with largely isolated individual xylem vessels.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143796438","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":"Mixed hydraulic responses to drought in six common woody species from a dry evergreen sclerophyll forest in South Africa.","authors":"Robert P Skelton, Daniel Buttner, Alastair J Potts","doi":"10.1093/treephys/tpaf045","DOIUrl":"10.1093/treephys/tpaf045","url":null,"abstract":"<p><p>Despite the emergence of a general conceptual framework for woody tree response to drought, few studies link variation in functional traits of coexisting species to drought outcomes in diverse plant communities. We use a natural drought event to test an ecological prediction from the embolism avoidance hypothesis: that co-existing species of a single growth form (woody trees) will converge upon traits that avoid embolism during all but the most severe droughts. We evaluated hydraulic traits and drought responses of six common woody tree species from South Africa's Albany Subtropical Thicket. For each species, we measured laboratory-based xylem vulnerability and Pressure-Volume curves, and in situ minimum water potentials and four metrics of drought canopy damage during a dry period as well as a subsequent wetter period. We also quantified leaf construction and plant architecture traits, including tree height, Huber value and leaf mass per area (LMA). Species varied in the water potential associated with 50% loss of xylem function (P50), and turgor loss point, leading to between-species variation in stomatal and hydraulic safety margins. All species were shown to withstand leaf xylem water potentials more negative than -4.5 MPa before experiencing embolism. Predicted percent embolism during the dry period was associated with whole-plant drought damage but only following recovery. The LMA, modulus of elasticity, Huber value and tree height were also associated with drought damage, albeit less predictably so. Our results provide support for the embolism avoidance hypothesis and demonstrate how knowledge of species' hydraulic traits can predict canopy dieback during drought events. However, our study also reveals mixed functional responses to drought within a single major growth form (i.e., woody trees) within a community that is composed of multiple growth forms, highlighting the complexity of predicting drought outcomes in diverse communities.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12106281/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143988241","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":"Transcriptomic profiling reveals bud dormancy stage dynamics in Japanese cedar (Cryptomeria japonica) throughout the nongrowing period.","authors":"Mine Nose, Yuichiro Hiraoka, Masahiro Miura","doi":"10.1093/treephys/tpaf017","DOIUrl":"https://doi.org/10.1093/treephys/tpaf017","url":null,"abstract":"<p><p>This study aimed to characterize the vegetative bud status of Japanese cedar (Cryptomeria japonica [L.f.] D. Don) throughout the nongrowing period (October-March). Based on the results of twig experiments and transcriptome analysis, we divided the nongrowing period into four stages. Buds were estimated to form between October and November (stage 1), with bud hardening continuing until December (stage 2). Endodormancy was released and transitioned into ecodormancy in mid-to-late December, with the timing varying by genotype. Buds endured harsh winter conditions during January and February (stage 3) and prepared for subsequent growth in March (stage 4). The number of days to bud burst (DBB) under forcing conditions gradually decreased after the transition to ecodormancy, culminating in bud burst in the field in late April. Transcriptome analysis identified key genes presumed to regulate these stages, such as CONSTANS-like and core clock genes. Furthermore, analysis of three genotypes with differing dormancy characteristics revealed DBB-associated genes, indicating the potential involvement of phytohormone cytokinins in regulating bud burst. Additionally, the PEBP- and SVP-like genes, known for their roles in dormancy regulation in other tree species, exhibited distinct expression patterns in Japanese cedar, highlighting variations in dormancy control mechanisms. This study is the first to categorize bud dormancy stages in conifers during the nongrowing period based on molecular data, and the results provide foundational insights for future investigations into conifer dormancy.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":"45 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143982949","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":"Physiological symptoms induced by drought stress outweigh vascular pathogen infection in walnut.","authors":"Israel Jiménez Luna, Louis Santiago, Exequiel Ezcurra, MengYuan Xi, Vanessa E T M Ashworth, Eugene Nothnagel, Philippe E Rolshausen","doi":"10.1093/treephys/tpaf034","DOIUrl":"10.1093/treephys/tpaf034","url":null,"abstract":"<p><p>Drought stress can affect the success of xylem-dwelling pathogens due to modifications of the xylem environment as water potential declines. However, the interaction between these abiotic and biotic stresses on plants is complex and requires specific experiments to distinguish between multiple effects. This is especially important in agroecosystems, where monocultures of individuals facilitate disease transmission and water scarcity can lead to deficit irrigation practices to optimize water management, control canopy size and maintain crop productivity. We measured photosynthetic gas exchange, stem xylem water potential, non-structural carbohydrates (NSC), morphology and growth of walnut trees in response to two imposed stress treatments. One was the inoculation with the two cosmopolitan vascular fungal pathogens Diplodia mutila and Neofusicoccum parvum. The other was a manipulation of water availability with well-watered controls compared to deficit irrigation treatments representing 75% and 25% of well-watered controls. We found that deficit irrigation significantly reduced all measures of gas exchange and stem xylem water potential, and most morphological, growth and NSC variables. Signs of severe drought with leaf yellowing and senescing occurred at the end of the experiment when leaf water potential reached -1.6 MPa. In contrast, responses to pathogen inoculation were limited to reduced stem xylem water potential, total plant leaf area and leaf area ratio. There was no reduction in photosynthetic rate per leaf area with pathogen inoculation, but the reduction in whole plant leaf area led to an overall reduction in whole plant photosynthesis. Pathogen-induced effects were independent of the plant water status, yet they were only visible in fully irrigated trees suggesting that drought minimizes the scope of measurable symptoms. Biotic damage was not enhanced under drought stress perhaps indicating that the host had not reached a critical water stress status conducive to pathogen virulence.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12062578/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143721623","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":"Needle age-dependent defence of Scots pine against insect herbivory.","authors":"Asifur Rahman-Soad, Sophie Krause, Laura Hagemann, Monika Hilker","doi":"10.1093/treephys/tpaf046","DOIUrl":"10.1093/treephys/tpaf046","url":null,"abstract":"<p><p>Plant defence responses to herbivory vary with foliage age, which in angiosperms lasts a few months, but may be several years in conifers. While age-dependent leaf responses of angiosperms to insect herbivory are well studied, much less is known about anti-herbivore responses of conifer needles that differ in age by a year or more. Similarly, insect responses to conifer foliage that differs in age by years have rarely been studied. Here, we used Pinus sylvestris L. (Scots pine) and the herbivorous sawfly Diprion pini to elucidate (i) the responses of this herbivore to pine needles of different age and (ii) needle age-dependent differences in two anti-herbivore plant defence traits, rarely studied in interactions of conifers and phyllophagous insects, i.e., phytohormones and proteinase inhibitor (PI) activity. The sawfly D. pini preferred old (previous year) over young (current year) pine needles for oviposition and feeding by late larval instars. The insect benefited from these preferences through higher egg survival rates on old needles and more larval weight when feeding upon old needles. Scots pine needles showed needle-age dependent differences in their phytohormonal responses to D. pini larval feeding. Feeding-induced concentrations of salicylic acid and abscisic acid were higher in young than old needles. No such age dependency was detected for herbivory-induced changes in levels of jasmonic acid, in contrast to known, age-dependent jasmonic acid responses to damage in angiosperms. Contrary to angiosperms, PI activities of pine were not induced by sawfly feeding upon young or old needles. However, old needles showed constitutively significantly lower PI activities, which are discussed with respect to the benefits that D. pini gains when preferring old needles. Our results highlight the developmental plasticity of defence traits of conifer foliage as well as the adaptation of a pine herbivore specialist to these defences.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144036459","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}