Tree physiologyPub Date : 2025-06-05DOI: 10.1093/treephys/tpaf070
Santiago González-Carrera, Alfonso Escudero, Ignacio Martín, Montserrat Martínez-Ortega, Sonia Mediavilla
{"title":"Correspondence between genetic data and leaf morphological and anatomical traits in two Mediterranean Quercus and their hybrids along environmental gradients.","authors":"Santiago González-Carrera, Alfonso Escudero, Ignacio Martín, Montserrat Martínez-Ortega, Sonia Mediavilla","doi":"10.1093/treephys/tpaf070","DOIUrl":"https://doi.org/10.1093/treephys/tpaf070","url":null,"abstract":"<p><p>Oaks are known for their frequent hybridization, a trend that generates a wide phenotypic spectrum and produces taxonomic confusion within the genus. Different approaches are needed for hybrids characterization, such as a combination of leaf morphological and anatomical traits supported by molecular data. Here, we characterized some morphological and anatomical (veins and stomata) leaf traits and their changes across a temperature gradient of two closely related Mediterranean Quercus species (Q. faginea Lam. and Q. pyrenaica Willd.) and their hybrids, preliminarily identified from molecular markers. Q. faginea tended to exhibit more drought-adapted traits (smaller leaf size, larger vein and stomatal density, but lower stomatal index) than Q. pyrenaica. Q. faginea also tended to exhibit stronger responses to environmental changes between the climatic zones. Hybrids possessed intermediate stomatal and vein traits between the two parent species but they were similar to Q. faginea for most morphological traits. For a few leaf shape parameters, such as the length/maximum width ratio, hybrids tended to exhibit larger values than both parent species. Whether this transgressive character of the hybrids affects their fitness in the contact zones between the two parent species needs to be better investigated. For the three genetic groups there were consistent changes in morphological traits across the climatic gradient. By contrast, stomatal and vein traits did not show significant within-species changes across the gradient. Leaf size decreased with decreasing temperatures, mainly due to a strong reduction of maximum leaf width. It is known that a reduced leaf size leads to the reduction of the thickness of the air boundary layer at the leaf surface. We suggest that the smaller leaf sizes at the colder sites would constitute an adaptation to avoid frost damage, given the trend of large leaves with thick boundary layers to develop nighttime temperatures lower than air temperatures.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144226841","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":"Co-expression of SfGPX and SfGST in Nicotiana benthamiana and two Spiraea species further regulates their low-temperature tolerance mechanism.","authors":"Feng Qian, Hao Sun, Hui Zhang, Bingbing Lu, Ziyin Cheng, Zili Jin, Feifan Xu, Huimin Liu","doi":"10.1093/treephys/tpaf069","DOIUrl":"https://doi.org/10.1093/treephys/tpaf069","url":null,"abstract":"<p><p>Spiraea fritschiana (S. fritschiana) is widely cultivated in horticulture and exhibits strong cold tolerance. We identified both glutathione peroxidases (GPXs) and glutathione S-transferases (GSTs) as key proteins involved in the low-temperature response of S. fritschiana. Both enzymes are known to participate in reactive oxygen species (ROS) scavenging through the ascorbate-glutathione cycle. Previous experiments have demonstrated that both SfGPX and SfGST are localized in the cytoplasm and exhibit responsiveness to low-temperature induction. In this context, we hypothesize a potential functional interplay between these two genes in mediating Spiraea's cold tolerance. To elucidate the functional interplay between SfGPX and SfGST in cold stress adaptation, this study employed yeast two-hybrid (Y2H) and luciferase complementation assays (LCA) to validate their protein-protein interactions, providing a foundation for further mechanistic studies. Meanwhile, we constructed SfGPX, SfGST overexpressing and SfGPX/SfGST co-overexpressing lines of Nicotiana benthamiana (N. benthamiana). And monitored phenotypic alterations and quantified key physiological parameters related to cold tolerance, photosynthetic performance and Ca2+ signaling in all transgenic lines under low-temperature conditions. Transient overexpression of SfGPX, SfGST, and SfGPX/SfGST in Spiraea japonica 'Gold Mound' (S. japonica 'Gold Mound'), and transient editing of these genes in S. fritschiana were performed. The relative electrical conductivity (REC) was detected in each line under low temperature. The results showed that both Y2H and LCA detected no direct SfGPX-SfGST interaction under our experimental conditions. Under low-temperature stress conditions, SfGPX/SfGST co-overexpressing N. benthamiana lines exhibited significantly improved cold tolerance compared to single-gene overexpression lines. Co-overexpression of SfGPX/SfGST in S. japonica 'Gold Mound' reduced REC under cold stress versus single-gene lines, while co-edited S. fritschiana showed increased REC. This result suggests that while SfGPX and SfGST do not exhibit a reciprocal relationship in regulating low-temperature tolerance in tobacco and the two Spiraea species, their co-expression demonstrates a synergistic effect.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144226840","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}
Tree physiologyPub Date : 2025-06-03DOI: 10.1093/treephys/tpaf063
Mauro Brum, Raimundo Cosme Oliveira-Junior, Luciana F Alves, Elizabeth Agee, Luciano Pereira, Deliane Penha, Carina Araujo, Juliana L S Mayer, Victor Hugo Moutinho, Rafael S Oliveira, Scott Stark, Scott R Saleska
{"title":"Unveiling the integration of above and below-ground tree carbon-hydraulic traits in Amazonian trees across hydrological niches.","authors":"Mauro Brum, Raimundo Cosme Oliveira-Junior, Luciana F Alves, Elizabeth Agee, Luciano Pereira, Deliane Penha, Carina Araujo, Juliana L S Mayer, Victor Hugo Moutinho, Rafael S Oliveira, Scott Stark, Scott R Saleska","doi":"10.1093/treephys/tpaf063","DOIUrl":"https://doi.org/10.1093/treephys/tpaf063","url":null,"abstract":"<p><p>Understanding trait coordination and trade-offs along the root-to-leaf hydraulic pathway is critical for assessing forest functioning, as these traits significantly impact ecosystem carbon allocation and water use. Here, we investigated the relationship between carbon and hydraulic traits in 11 Amazonian tree species distributed across vertically structured hydrological niches. Using a carbon-hydraulic framework, we tested the hypothesis that interspecific differences arise from the optimization of xylem hydraulic efficiency, reflecting how tropical trees balance water transport efficiency with the carbon costs of maintaining transport tissues across vertical canopy positions. Our results show that above-ground traits were largely explained by canopy position (vertical stratification), whereas below-ground carbon-hydraulic traits were predominantly influenced by interspecific differences. Overstory trees exhibited lower and less variable specific root length (SRL) than shallow-rooted understory trees, indicating divergent carbon allocation strategies. Thicker terminal roots had higher hydraulic conductivity (Ks) than finer roots, but Ks declined from roots to terminal branches in most species. Additionally, branch and leaf Ks increase with tree size, indicating greater hydraulic efficiency in larger canopy species. Below-ground, we presented evidence that an increase in SRL is linked to decreased hydraulic conductivity and is influenced by root diameter. Above-ground, branch and leaf hydraulic conductivity tend to be higher in species with higher wood density, which are also more prevalent in upper canopy layers. Together, our findings reveal a coordinated above- and belowground carbon-hydraulic trait framework across Amazonian trees, Species that occupy different vertical above-ground hydrological niches in lowland Amazon forests exhibit different carbon allocation strategies, which helps explain variation in species dominance and resource use throughout the vertical forest profile.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144209521","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}
Tree physiologyPub Date : 2025-06-03DOI: 10.1093/treephys/tpaf066
Andrea Ganthaler, Carlos Trujillo-Moya, Stefanie Burger, Juraj Hlavaty, Stefan Kummer, Waltraud Tschulenk, Ingrid Walter
{"title":"Infection of Norway spruce by Chrysomyxa rhododendri: Ultrastructural insights into plant-pathogen interactions reveal differences between resistant and susceptible trees.","authors":"Andrea Ganthaler, Carlos Trujillo-Moya, Stefanie Burger, Juraj Hlavaty, Stefan Kummer, Waltraud Tschulenk, Ingrid Walter","doi":"10.1093/treephys/tpaf066","DOIUrl":"https://doi.org/10.1093/treephys/tpaf066","url":null,"abstract":"<p><p>Infection of Norway spruce (Picea abies L.) by the rust Chrysomyxa rhododendri is a major problem in European subalpine forests, causing severe defoliation and reduced growth. However, as with most pathogens from high elevation environments, little is known about the host-pathogen interaction, the associated plant cellular damage and responses, and their differential expression in susceptible and resistant host trees. Here we report on the development of the biotrophic pathogen in the host tissues, from infection by basidiospores to release of aeciospores, by analysing needles at different time points after infection by histology and transmission electron microscopy. Ultrastructural changes in the host cells, ranging from cell reorganisation and degradation to the accumulation of secondary compounds, were localized and characterized in both susceptible and a resistant genotype. C. rhododendri formed a dense mycelium in the intercellular spaces of the needle mesophyll of susceptible trees, followed by the formation of subepidermal spermogonia and aecia. Symptomatic needle yellowing corresponded to the spatial expansion of the mycelium and was caused by degradation, but not collapse, of the mesophyll cells with chloroplasts. In needles of the enhanced resistant genotype PRA-R, only few fungal hyphae appeared, but distinct modifications of the cell walls and an accumulation of electron dense material in the intercellular space appeared. In addition, large tannin droplets were observed around fungal structures, indicating an increased accumulation of polyphenols. The findings are consistent with observations on other heterocyclic rusts and with known physiological and molecular responses of infected trees, including a reduced photosynthetic activity, changes in the needle phenolic profile and a local hypersensitive response. Highly resistant trees may be able to limit fungal growth and associated damage by rapidly enhancing structural and chemical barriers in the needle mesophyll.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144209520","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":"https://doi.org/10.1093/treephys/tpaf068","url":null,"abstract":"<p><p>Phoebe bournei, 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 PEG treatment, ABA, and natural drought stress. Interestingly, 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":"2025-06-02","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}
Tree physiologyPub Date : 2025-06-02DOI: 10.1093/treephys/tpaf038
Lijuan Jiang, Hua Yang, Yunshuang Du, Zhaoliang Zheng, Shanshan Ding, Xinyan Zhang, Xingliang Yao, Gongfu Ye, Jun Su, Jian Li
{"title":"Phosphorus deficiency suppresses the trans-zeatin riboside accumulation by up-regulating CeIPT5, promoting root elongation and phosphorus absorption efficiency of Casuarina equisetifolia.","authors":"Lijuan Jiang, Hua Yang, Yunshuang Du, Zhaoliang Zheng, Shanshan Ding, Xinyan Zhang, Xingliang Yao, Gongfu Ye, Jun Su, Jian Li","doi":"10.1093/treephys/tpaf038","DOIUrl":"10.1093/treephys/tpaf038","url":null,"abstract":"<p><p>Phosphorus (P) deficiency is critical to the renewal barrier of she-oak (Casuarina equisetifolia), an important tree species used for coastal protection. However, the response of she-oak to P deficiency remains unclear. In this study, we compared the phenotypes of two she-oak cultivars, the P deficiency-sensitive 'Chihu219' and the insensitive 'Chihu397', and found that P deficiency significantly increased root growth, P concentration and phosphorus absorption efficiency (PAE) in Chihu219, but not in Chihu397. We also analyzed the transcriptome and metabolome of these cultivars under different P conditions and showed that trans-zeatin riboside (tZR) levels were highly suppressed by P deficiency in Chihu219, but not in Chihu397. Furthermore, exogenous tZR suppressed both root P concentration and PAE while promoting P-use efficiency. We also identified CeIPT5 (isopentenyltransferase 5) as a key regulatory gene of tZR biosynthesis and found that its expression was more highly induced by P deficiency in Chihu219 than in Chihu397. We also showed that overexpression of CeIPT5 in insensitive she-oak lines reduced tZR concentration and increased root P concentration compared with the vector control. Taken together, P deficiency can greatly reduce tZR accumulation in P deficiency-insensitive she-oak at least by activating the tZR accumulation regulatory gene, CeIPT5, thereby promoting root elongation and P concentration. This study not only provides a genetic basis for enhancing PAE in woody plants but also establishes a theoretical basis for optimizing root structure and improving nutrient utilization efficiency, thereby promoting sustainable forestry development.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143754518","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}
Tree physiologyPub Date : 2025-06-02DOI: 10.1093/treephys/tpaf057
Richard L Peters, Katrin Meusburger
{"title":"The challenge of unravelling tree water-use strategies-balancing deep root-water uptake vs water reserves.","authors":"Richard L Peters, Katrin Meusburger","doi":"10.1093/treephys/tpaf057","DOIUrl":"10.1093/treephys/tpaf057","url":null,"abstract":"","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144080647","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}
Tree physiologyPub Date : 2025-06-02DOI: 10.1093/treephys/tpaf058
Martijn van den Ende, Eléonore Oberlé, Thierry Améglio, Robin Ardito, Gildas Gâteblé
{"title":"Using fibre-optic sensing for non-invasive, continuous dendrometry of mature tree trunks.","authors":"Martijn van den Ende, Eléonore Oberlé, Thierry Améglio, Robin Ardito, Gildas Gâteblé","doi":"10.1093/treephys/tpaf058","DOIUrl":"10.1093/treephys/tpaf058","url":null,"abstract":"<p><p>Dendrometry is the main non-invasive macroscopic technique commonly used in plant physiology and ecophysysiology studies. Over the years several types of dendrometric techniques have been developed, each with their respective strengths and drawbacks. Automatic and continuous monitoring solutions are being developed, but are still limited, particularly for non-invasive monitoring of large-diameter trunks. In this study, we propose a new type of automated dendrometer based on distributed fibre-optic sensing that continuously measures the change in stem circumference, is non-invasive and has no upper limit on the trunk diameter on which it can be installed. We performed a 3-month validation experiment during which we deployed a fibre-optic cable at three localities around the trunks of two specimens of Brachychiton. We verified the accuracy of this new method through comparison with a conventional point-dendrometer, and we observed a consistent time lag between the various measurement locations that varies with the meteorological conditions. Finally, we discuss the feasibility of the fibre-based dendrometer in the context of existing dendrometric techniques and practical experimental considerations.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144112170","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}
Tree physiologyPub Date : 2025-06-02DOI: 10.1093/treephys/tpaf059
Jin Cheng, Muhammad Riaz, Saba Babar, Yu Liu, Siyun Xiao, Cuncang Jiang
{"title":"New insights into alleviation mechanism of boron on H+ toxicity in Poncirus trifoliate: evidence from the stabled intracellular pH to the repaired plasma membrane.","authors":"Jin Cheng, Muhammad Riaz, Saba Babar, Yu Liu, Siyun Xiao, Cuncang Jiang","doi":"10.1093/treephys/tpaf059","DOIUrl":"10.1093/treephys/tpaf059","url":null,"abstract":"<p><p>Inappropriate fertilization and poor management practices in citrus orchards can cause soil acidification, which may result in potential proton (H+) toxicity to citrus roots. It has been reported that boron (B) can mediate H+ detoxification in citrus; however, the mechanisms remain limited. Herein, a hydroponic experiment was employed to unravel the alleviation mechanism of B on H+ toxicity at pH 4 in trifoliate (Poncirus trifoliate (L.) Raf.) seedlings. H+ toxicity reduced cytoplasmic pH from 7.2 (control) to 6.9 and vacuolar pH from 5.6 (control) to 5.4. This severely damaged the plasma membrane (PM) and inhibited root activity by 35%. However, B supplementation restored cytoplasmic pH to 7.1 and vacuolar pH to 5.6, enhancing root activity by 52% and reducing membrane permeability (relative conductivity decreased by 28%). Mechanistically, B upregulated phosphorylated-type adenosine triphosphatase activity by 14%; conversely, it suppressed vacuolar-type adenosine triphosphatase hyperactivity by 9% to stabilize vacuolar pH. Furthermore, B restored PM integrity by increasing phospholipid (40%), glycolipid (50%) and sulfhydryl group (28%) content, critical for membrane structure and function. It is concluded that B can alleviate root growth inhibition induced by H+ toxicity via increasing the content of key components of PM, which not only repairs the damaged PM but also maintains cellular pH homeostasis through enzyme regulation. The improvement of citrus growth correspondingly safeguards the production capacity.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144080644","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}