Pub Date : 2024-09-03DOI: 10.1093/treephys/tpae095
Alexandra M Barry, Bean Bein, Yong-Jiang Zhang, Jay W Wason
Climate change is raising concerns about how forests will respond to extreme droughts, heat waves and their co-occurrence. In this greenhouse study, we tested how carbon and water relations relate to seedling growth and mortality of northeastern US trees during and after extreme drought, warming, and combined drought and warming. We compared the response of our focal species red spruce (Picea rubens Sarg.) with a common associate (paper birch, Betula papyrifera Marsh.) and a species expected to increase abundance in this region with climate change (northern red oak, Quercus rubra L.). We tracked growth and mortality, photosynthesis and water use of 216 seedlings of these species through a treatment and a recovery year. Each red spruce seedling was planted in containers either alone or with another seedling to simulate potential competition, and the seedlings were exposed to combinations of drought (irrigated, 15-d 'short' or 30-d 'long') and temperature (ambient or 16 days at +3.5 °C daily maximum) treatments. We found dominant effects of the drought reducing photosynthesis, midday water potential, and growth of spruce and birch, but that oak showed considerable resistance to drought stress. The effects of planting seedlings together were moderate and likely due to competition for limited water. Despite high temperatures reducing photosynthesis for all species, the warming imposed in this study minorly impacted growth only for oak in the recovery year. Overall, we found that the diverse water-use strategies employed by the species in our study related to their growth and recovery following drought stress. This study provides physiological evidence to support the prediction that native species to this region like red spruce and paper birch are susceptible to future climate extremes that may favor other species like northern red oak, leading to potential impacts on tree community dynamics under climate change.
{"title":"Linking physiological drought resistance traits to growth and mortality of three northeastern tree species.","authors":"Alexandra M Barry, Bean Bein, Yong-Jiang Zhang, Jay W Wason","doi":"10.1093/treephys/tpae095","DOIUrl":"10.1093/treephys/tpae095","url":null,"abstract":"<p><p>Climate change is raising concerns about how forests will respond to extreme droughts, heat waves and their co-occurrence. In this greenhouse study, we tested how carbon and water relations relate to seedling growth and mortality of northeastern US trees during and after extreme drought, warming, and combined drought and warming. We compared the response of our focal species red spruce (Picea rubens Sarg.) with a common associate (paper birch, Betula papyrifera Marsh.) and a species expected to increase abundance in this region with climate change (northern red oak, Quercus rubra L.). We tracked growth and mortality, photosynthesis and water use of 216 seedlings of these species through a treatment and a recovery year. Each red spruce seedling was planted in containers either alone or with another seedling to simulate potential competition, and the seedlings were exposed to combinations of drought (irrigated, 15-d 'short' or 30-d 'long') and temperature (ambient or 16 days at +3.5 °C daily maximum) treatments. We found dominant effects of the drought reducing photosynthesis, midday water potential, and growth of spruce and birch, but that oak showed considerable resistance to drought stress. The effects of planting seedlings together were moderate and likely due to competition for limited water. Despite high temperatures reducing photosynthesis for all species, the warming imposed in this study minorly impacted growth only for oak in the recovery year. Overall, we found that the diverse water-use strategies employed by the species in our study related to their growth and recovery following drought stress. This study provides physiological evidence to support the prediction that native species to this region like red spruce and paper birch are susceptible to future climate extremes that may favor other species like northern red oak, leading to potential impacts on tree community dynamics under climate change.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141793492","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}
Pub Date : 2024-09-03DOI: 10.1093/treephys/tpae105
Hongyan Su, Yingtian Guo, Liang Gu, Xiaomeng Shi, Yangyan Zhou, Fanlin Wu, Lei Wang
Drought is a significant global issue affecting agricultural production, and the utilization of beneficial rhizosphere microorganisms is one of the effective ways to increase the productivity of crops and forest under drought. In this study, we characterized a novel growth-promoting dark septate endophytes (DSE) fungus R16 (Dothideomycetes sp.) derived from blueberry roots. Hyphae or microsclerotia were visible within the epidermal or cortical cells of R16-colonized blueberry roots, which was consistent with the typical characteristics of DSE fungi. Inoculation with R16 promoted the growth of blueberry seedlings, and the advantage over the control group was more significant under PEG-induced drought. Comparison of physiological indicators related to drought resistance between the inoculated and control groups was performed on the potted blueberry plants, including the chlorophyll content, net photosynthetic rate, root activities, malondialdehyde and H2O2 content, which indicated that R16 colonization mitigated drought injury in blueberry plants. We further analyzed the effects of R16 on phytohormones and non-structural carbohydrates (NSCs) to explore the mechanism of increased drought tolerance by R16 in blueberry seedlings. The results showed that except for the gibberellin content, indole-3-acetic acid, zeatin and abscisic acid varied significantly between the inoculated and control groups. Sucrose phosphate synthase and sorbitol-6-phosphate dehydrogenase activities in mature leaves, the key enzymes responsible for sucrose and sorbitol synthesis, respectively, as well as sorbitol dehydrogenase, sucrose synthase, cell wall invertase, hexokinase and fructokinase in roots, the key enzymes involved in the NSCs metabolism, showed significant differences between the inoculated and control groups before and after drought treatment. These results suggested that the positive effects of R16 colonization on the drought tolerance of blueberry seedlings are partially attributable to the regulation of phytohormone and sugar metabolism. This study provided valuable information for the research on the interaction between DSE fungi and host plants as well as the application of DSE preparations in agriculture.
{"title":"A novel growth-promoting dark septate endophytic fungus improved drought tolerance in blueberries by modulating phytohormones and non-structural carbohydrates.","authors":"Hongyan Su, Yingtian Guo, Liang Gu, Xiaomeng Shi, Yangyan Zhou, Fanlin Wu, Lei Wang","doi":"10.1093/treephys/tpae105","DOIUrl":"10.1093/treephys/tpae105","url":null,"abstract":"<p><p>Drought is a significant global issue affecting agricultural production, and the utilization of beneficial rhizosphere microorganisms is one of the effective ways to increase the productivity of crops and forest under drought. In this study, we characterized a novel growth-promoting dark septate endophytes (DSE) fungus R16 (Dothideomycetes sp.) derived from blueberry roots. Hyphae or microsclerotia were visible within the epidermal or cortical cells of R16-colonized blueberry roots, which was consistent with the typical characteristics of DSE fungi. Inoculation with R16 promoted the growth of blueberry seedlings, and the advantage over the control group was more significant under PEG-induced drought. Comparison of physiological indicators related to drought resistance between the inoculated and control groups was performed on the potted blueberry plants, including the chlorophyll content, net photosynthetic rate, root activities, malondialdehyde and H2O2 content, which indicated that R16 colonization mitigated drought injury in blueberry plants. We further analyzed the effects of R16 on phytohormones and non-structural carbohydrates (NSCs) to explore the mechanism of increased drought tolerance by R16 in blueberry seedlings. The results showed that except for the gibberellin content, indole-3-acetic acid, zeatin and abscisic acid varied significantly between the inoculated and control groups. Sucrose phosphate synthase and sorbitol-6-phosphate dehydrogenase activities in mature leaves, the key enzymes responsible for sucrose and sorbitol synthesis, respectively, as well as sorbitol dehydrogenase, sucrose synthase, cell wall invertase, hexokinase and fructokinase in roots, the key enzymes involved in the NSCs metabolism, showed significant differences between the inoculated and control groups before and after drought treatment. These results suggested that the positive effects of R16 colonization on the drought tolerance of blueberry seedlings are partially attributable to the regulation of phytohormone and sugar metabolism. This study provided valuable information for the research on the interaction between DSE fungi and host plants as well as the application of DSE preparations in agriculture.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142009518","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}
Tropical montane evergreen broad-leaved forests cover the majority of forest areas and have high carbon storage in Xishuangbanna, southwest China. However, stem radial growth dynamics and their correlations with climate factors have never been analyzed in this forest type. By combining bi-weekly microcoring and high-resolution dendrometer measurements, we monitored xylogenesis and stem radius variations of the deciduous species Betula alnoides Buch.-Ham. ex D. Don and the evergreen species Schima wallichii (DC.) Korth. We analyzed the relationships between weekly climate variables prior to sampling and the enlarging zone width or wall-thickening zone width, as well as weekly radial increments and climate factors during two consecutive years (2020 to 2021) showing contrasting hydrothermal conditions in the pre-monsoon season. In the year 2020, which was characterized by a warmer and drier pre-monsoon season, the onset of xylogenesis and radial increments of B. alnoides and S. wallichii were delayed by three months and one month, respectively, compared with the year 2021. In 2020, xylem formation and radial increments were significantly reduced for B. alnoides, but not for S. wallichii. The thickness of enlarging zone and wall-thickening zone in S. wallichii were positively correlated with relative humidity, and minimum and mean air temperature, but were negatively correlated with vapor pressure deficit during 2020 to 2021. The radial increments of both species showed significant positive correlations with precipitation and relative humidity, and negative correlations with vapor pressure deficit and maximum air temperature during two years. Our findings reveal that drier pre-monsoon conditions strongly delay growth initiation and reduce stem radial growth, providing deep insights to understand tree growth and carbon sequestration potential in tropical forests under a predicted increase in frequent drought events.
{"title":"Impact of extreme pre-monsoon drought on xylogenesis and intra-annual radial increments of two tree species in a tropical montane evergreen broad-leaved forest, southwest China.","authors":"Ya-Nan Liu, Ze-Xin Fan, You-Xing Lin, Arisa Kaewmano, Xiao-Lian Wei, Pei-Li Fu, Jussi Grießinger, Achim Bräuning","doi":"10.1093/treephys/tpae086","DOIUrl":"10.1093/treephys/tpae086","url":null,"abstract":"<p><p>Tropical montane evergreen broad-leaved forests cover the majority of forest areas and have high carbon storage in Xishuangbanna, southwest China. However, stem radial growth dynamics and their correlations with climate factors have never been analyzed in this forest type. By combining bi-weekly microcoring and high-resolution dendrometer measurements, we monitored xylogenesis and stem radius variations of the deciduous species Betula alnoides Buch.-Ham. ex D. Don and the evergreen species Schima wallichii (DC.) Korth. We analyzed the relationships between weekly climate variables prior to sampling and the enlarging zone width or wall-thickening zone width, as well as weekly radial increments and climate factors during two consecutive years (2020 to 2021) showing contrasting hydrothermal conditions in the pre-monsoon season. In the year 2020, which was characterized by a warmer and drier pre-monsoon season, the onset of xylogenesis and radial increments of B. alnoides and S. wallichii were delayed by three months and one month, respectively, compared with the year 2021. In 2020, xylem formation and radial increments were significantly reduced for B. alnoides, but not for S. wallichii. The thickness of enlarging zone and wall-thickening zone in S. wallichii were positively correlated with relative humidity, and minimum and mean air temperature, but were negatively correlated with vapor pressure deficit during 2020 to 2021. The radial increments of both species showed significant positive correlations with precipitation and relative humidity, and negative correlations with vapor pressure deficit and maximum air temperature during two years. Our findings reveal that drier pre-monsoon conditions strongly delay growth initiation and reduce stem radial growth, providing deep insights to understand tree growth and carbon sequestration potential in tropical forests under a predicted increase in frequent drought events.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11387012/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141727893","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}
Increases in temperatures and atmospheric CO2 concentration influence the growth performance of trees worldwide. The direction and intensity of tree growth and physiological responses to changing climate do, however, vary according to environmental conditions. Here we present complex, long-term, tree-physiological responses to unprecedented temperature increase in East Asia. For this purpose, we studied radial growth and isotopic (δ13C and δ18O) variations using tree-ring data for the past 100 yr of dominant Quercus mongolica trees from the cool-temperate forests from Hallasan, South Korea. Overall, we found that tree stem basal area increment, intercellular CO2 concentration and intrinsic water-use efficiency significantly increased over the last century. We observed, however, short-term variability in the trends of these variables among four periods identified by change point analysis. In comparison, δ18O did not show significant changes over time, suggesting no major hydrological changes in this precipitation-rich area. The strength and direction of growth-climate relationships also varied during the past 100 yr. Basal area increment (BAI) did not show significant relationships with the climate over the 1924-1949 and 1975-1999 periods. However, over 1950-1974, BAI was negatively affected by both temperature and precipitation, while after 2000, a temperature stimulus was observed. Finally, over the past two decades, the increase in Q. mongolica tree growth accelerated and was associated with high spring-summer temperatures and atmospheric CO2 concentrations and decreasing intrinsic water-use efficiency, δ18O and vapour pressure deficit, suggesting that the photosynthetic rate continued increasing under no water limitations. Our results indicate that the performance of dominant trees of one of the most widely distributed species in East Asia has benefited from recent global changes, mainly over the past two decades. Such findings are essential for projections of forest dynamics and carbon sequestration under climate change.
{"title":"Recent warming and increasing CO2 stimulate growth of dominant trees under no water limitation in South Korea.","authors":"Julieta Gabriela Arco Molina, Matthias Saurer, Nela Altmanova, Kerstin Treydte, Jiri Dolezal, Jong-Suk Song, Jan Altman","doi":"10.1093/treephys/tpae103","DOIUrl":"10.1093/treephys/tpae103","url":null,"abstract":"<p><p>Increases in temperatures and atmospheric CO2 concentration influence the growth performance of trees worldwide. The direction and intensity of tree growth and physiological responses to changing climate do, however, vary according to environmental conditions. Here we present complex, long-term, tree-physiological responses to unprecedented temperature increase in East Asia. For this purpose, we studied radial growth and isotopic (δ13C and δ18O) variations using tree-ring data for the past 100 yr of dominant Quercus mongolica trees from the cool-temperate forests from Hallasan, South Korea. Overall, we found that tree stem basal area increment, intercellular CO2 concentration and intrinsic water-use efficiency significantly increased over the last century. We observed, however, short-term variability in the trends of these variables among four periods identified by change point analysis. In comparison, δ18O did not show significant changes over time, suggesting no major hydrological changes in this precipitation-rich area. The strength and direction of growth-climate relationships also varied during the past 100 yr. Basal area increment (BAI) did not show significant relationships with the climate over the 1924-1949 and 1975-1999 periods. However, over 1950-1974, BAI was negatively affected by both temperature and precipitation, while after 2000, a temperature stimulus was observed. Finally, over the past two decades, the increase in Q. mongolica tree growth accelerated and was associated with high spring-summer temperatures and atmospheric CO2 concentrations and decreasing intrinsic water-use efficiency, δ18O and vapour pressure deficit, suggesting that the photosynthetic rate continued increasing under no water limitations. Our results indicate that the performance of dominant trees of one of the most widely distributed species in East Asia has benefited from recent global changes, mainly over the past two decades. Such findings are essential for projections of forest dynamics and carbon sequestration under climate change.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141992488","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}
Pub Date : 2024-08-13DOI: 10.1093/treephys/tpae100
Maurizio Mencuccini
{"title":"Scales and scaling in Tree Physiology.","authors":"Maurizio Mencuccini","doi":"10.1093/treephys/tpae100","DOIUrl":"https://doi.org/10.1093/treephys/tpae100","url":null,"abstract":"","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141971894","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}
Pub Date : 2024-08-03DOI: 10.1093/treephys/tpae081
Tatiana V Tarelkina, Aleksandra A Serkova, Natalia A Galibina, Elena V Novichonok, Sergei A Moshnikov, Diana S Ivanova, Ludmila I Semenova
In forests, a significant proportion of the carbon fixed by trees during photosynthesis is transported belowground along the conducting phloem, so variations in phloem anatomy can lead to variations in transport capacity. Phloem conductance at tree level (Ktree) is also affected by tree height. Both the phloem anatomy and the tree size change during ontogeny, and also differ under different environmental conditions. The goal of our work was to identify the main drivers of variation in Ktree in Scots pine trees growing in natural boreal forests. We conducted a phloem anatomical study and calculated Ktree in trees of three age groups growing in different climatic conditions along a latitudinal gradient from south to north. We found that Ktree was maintained at the same level in actively growing pine trees (25-80-years-old) but increased in old-aged trees (180-190-years-old), possibly reflecting the shift in source-sink relationships of aboveground and belowground parts of trees. Trees of the same age group growing in different climatic conditions demonstrated similar values of Ktree due to coordinated changes in the phloem anatomy and the tree height. In general, the negative influence of tree height on Ktree is offset by the positive influence of phloem width (or trunk diameter) and sieve cell diameter. The exception was young trees growing in the transition zone of the northern taiga subzone to the tundra, where Ktree was the highest in its age group and even exceeded Ktree of middle-aged trees.
{"title":"Estimation of phloem conductance at tree level in young, middle-aged and old-aged Scots pine trees growing in different climatic conditions in boreal forests.","authors":"Tatiana V Tarelkina, Aleksandra A Serkova, Natalia A Galibina, Elena V Novichonok, Sergei A Moshnikov, Diana S Ivanova, Ludmila I Semenova","doi":"10.1093/treephys/tpae081","DOIUrl":"10.1093/treephys/tpae081","url":null,"abstract":"<p><p>In forests, a significant proportion of the carbon fixed by trees during photosynthesis is transported belowground along the conducting phloem, so variations in phloem anatomy can lead to variations in transport capacity. Phloem conductance at tree level (Ktree) is also affected by tree height. Both the phloem anatomy and the tree size change during ontogeny, and also differ under different environmental conditions. The goal of our work was to identify the main drivers of variation in Ktree in Scots pine trees growing in natural boreal forests. We conducted a phloem anatomical study and calculated Ktree in trees of three age groups growing in different climatic conditions along a latitudinal gradient from south to north. We found that Ktree was maintained at the same level in actively growing pine trees (25-80-years-old) but increased in old-aged trees (180-190-years-old), possibly reflecting the shift in source-sink relationships of aboveground and belowground parts of trees. Trees of the same age group growing in different climatic conditions demonstrated similar values of Ktree due to coordinated changes in the phloem anatomy and the tree height. In general, the negative influence of tree height on Ktree is offset by the positive influence of phloem width (or trunk diameter) and sieve cell diameter. The exception was young trees growing in the transition zone of the northern taiga subzone to the tundra, where Ktree was the highest in its age group and even exceeded Ktree of middle-aged trees.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141555566","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}
Pub Date : 2024-08-03DOI: 10.1093/treephys/tpae101
{"title":"Correction to: Balance between carbon gain and loss in warmer environments: impacts on photosynthesis and leaf respiration in four temperate tree species.","authors":"","doi":"10.1093/treephys/tpae101","DOIUrl":"https://doi.org/10.1093/treephys/tpae101","url":null,"abstract":"","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142018713","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}
Olive (Olea europaea L.), an economically important oil-producing crop, is sensitive to low temperature, which severely limits its productivity and geographical distribution. However, the underlying mechanism of cold tolerance in olive remains elusive. In this study, a chilling experiment (4 °C) on the living saplings of two olive cultivars revealed that O. europaea cv. Arbequina showed stronger cold tolerance with greater photosynthetic activity compared with O. europaea cv. Leccino. Transcriptome analyses revealed that early light-inducible protein 1 (ELIP1), the main regulator for chlorophyll synthesis, is dramatically induced to protect the photosynthesis at low temperatures. Furthermore, weighted gene co-expression network analysis, yeast one-hybrid and luciferase assays demonstrated that transcription factor bHLH66 serves as an important regulator of ELIP1 transcription by binding to the G-box motif in the promoter. Taken together, our research revealed a novel transcriptional module consisting of bHLH66-ELIP1 in the adaptation of olive trees to cold stress.
{"title":"Comparative transcriptome provides new insights into the molecular regulation of olive trees to chilling stress.","authors":"Wenjun Wu, Chengying Jiang, Qianqian Wei, Ling He, Gaoming Jin, Yuming Zheng, Jianli Qi, Rong Zhang, Yufang Yao, Dongshi Wan, Jiaojiao Lv","doi":"10.1093/treephys/tpae075","DOIUrl":"10.1093/treephys/tpae075","url":null,"abstract":"<p><p>Olive (Olea europaea L.), an economically important oil-producing crop, is sensitive to low temperature, which severely limits its productivity and geographical distribution. However, the underlying mechanism of cold tolerance in olive remains elusive. In this study, a chilling experiment (4 °C) on the living saplings of two olive cultivars revealed that O. europaea cv. Arbequina showed stronger cold tolerance with greater photosynthetic activity compared with O. europaea cv. Leccino. Transcriptome analyses revealed that early light-inducible protein 1 (ELIP1), the main regulator for chlorophyll synthesis, is dramatically induced to protect the photosynthesis at low temperatures. Furthermore, weighted gene co-expression network analysis, yeast one-hybrid and luciferase assays demonstrated that transcription factor bHLH66 serves as an important regulator of ELIP1 transcription by binding to the G-box motif in the promoter. Taken together, our research revealed a novel transcriptional module consisting of bHLH66-ELIP1 in the adaptation of olive trees to cold stress.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141535397","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}
Pub Date : 2024-08-03DOI: 10.1093/treephys/tpae087
Horacio E Bown, John E Hunt, Margaret M Barbour, Graeme N D Rogers, David Whitehead
We tested an approach to estimate daily canopy net photosynthesis, A, based on estimates of transpiration, E, using measurements of sap flow and water-use efficiency, ω, by measuring δ13C in CO2 respired from shoots in the canopies of two conifers (Podocarpaceae) native to New Zealand. The trees were planted in adjacent 20-year-old stands with the same soil and environmental conditions. Leaf area index was lower for Dacrycarpus dacrydioides D.Don in Lamb (1.34 m2 m-2) than for Podocarpus totara G.Benn. ex D.Don var. totara (2.01 m2 m-2), but mean (± standard error) stem diameters were the same at 152 ± 21 mm for D. dacrydioides and 154 ± 25 mm for P. totara. Over a 28-day period, daily A (per unit ground area) ranged almost five-fold but there were no significant differences between species (mean 2.73 ± 1.02 gC m-2 day-1). This was attributable to higher daily values of E (2.63 ± 0.83 mm day-1) and lower ω (1.35 ± 0.53 gC kg H2O-1) for D. dacrydioides compared with lower E (1.82 ± 0.72 mm day-1) and higher ω (1.90 ± 0.77 gC kg H2O-1) for P. totara. We attributed this to higher nitrogen availability and nitrogen concentration per unit foliage area, Na, and greater exposure to irradiance in the D. dacrydioides canopy compared with P. totara. Our findings support earlier observations that D. dacrydioides is more adapted to sites with poor drainage. In contrast, the high retention of leaf area and maintaining low rates of transpiration by P. totara, resulting in higher water-use efficiency, is an adaptive response to survival in dry conditions. Our findings show that physiological adjustments for two species adapted to different environments led to similar canopy photosynthesis rates when the trees were grown in the same conditions. We demonstrated consistency between whole-tree and more intensive shoot-scale measurements, confirming that integrated approaches are appropriate for comparative estimates of carbon uptake in stands with different species.
我们通过测量新西兰原产的两种针叶树(荚果科)树冠中嫩枝呼吸的 CO2 中的δ13C,测试了一种基于蒸腾作用估算值 E 来估算树冠每日净光合作用 A 的方法。这些树木种植在相邻的 20 年树龄的林地中,土壤和环境条件相同。Dacrycarpus dacrydioides(1.34 m2 m-2)的叶面积指数低于 Podocarpus totara(2.01 m2 m-2),但平均(± 标准误差)茎直径相同,D. dacrydioides 为 152 ± 21 毫米,P. totara 为 154 ± 25 毫米。在 28 天的时间里,日 A(单位地面面积)几乎变化了五倍,但物种之间没有显著差异(平均 2.73 ± 1.02 gC m-2 d-1)。这是因为 D. dacrydioides 的日 E 值(2.63 ± 0.83 mm d-1)较高,ω 值(1.35 ± 0.53 gC kg H2O-1)较低,而 P. totara 的日 E 值(1.82 ± 0.72 mm d-1)较低,ω 值(1.90 ± 0.77 gC kg H2O-1)较高。我们认为这是由于 D. dacrydioides 树冠比 P. totara 更高的氮可用性和单位叶面积的氮浓度(Na)以及更高的辐照度造成的。我们的研究结果支持了之前的观察,即 D. dacrydioides 更适应排水不良的地点。相比之下,图腾草保持较高的叶面积和较低的蒸腾速率,从而提高了水分利用效率,这是一种在干旱条件下生存的适应性反应。我们的研究结果表明,两种适应不同环境的树种在相同条件下生长时,其生理调整会导致相似的树冠光合作用率。我们证明了整棵树和更密集的嫩枝尺度测量之间的一致性,从而证实了综合方法适用于比较估算不同树种林木的碳吸收量。
{"title":"Adaptation of stomatal conductance, photosynthesis and water-use efficiency at shoot and canopy scales in adjacent stands of Dacrycarpus dacrydioides and Podocarpus totara.","authors":"Horacio E Bown, John E Hunt, Margaret M Barbour, Graeme N D Rogers, David Whitehead","doi":"10.1093/treephys/tpae087","DOIUrl":"10.1093/treephys/tpae087","url":null,"abstract":"<p><p>We tested an approach to estimate daily canopy net photosynthesis, A, based on estimates of transpiration, E, using measurements of sap flow and water-use efficiency, ω, by measuring δ13C in CO2 respired from shoots in the canopies of two conifers (Podocarpaceae) native to New Zealand. The trees were planted in adjacent 20-year-old stands with the same soil and environmental conditions. Leaf area index was lower for Dacrycarpus dacrydioides D.Don in Lamb (1.34 m2 m-2) than for Podocarpus totara G.Benn. ex D.Don var. totara (2.01 m2 m-2), but mean (± standard error) stem diameters were the same at 152 ± 21 mm for D. dacrydioides and 154 ± 25 mm for P. totara. Over a 28-day period, daily A (per unit ground area) ranged almost five-fold but there were no significant differences between species (mean 2.73 ± 1.02 gC m-2 day-1). This was attributable to higher daily values of E (2.63 ± 0.83 mm day-1) and lower ω (1.35 ± 0.53 gC kg H2O-1) for D. dacrydioides compared with lower E (1.82 ± 0.72 mm day-1) and higher ω (1.90 ± 0.77 gC kg H2O-1) for P. totara. We attributed this to higher nitrogen availability and nitrogen concentration per unit foliage area, Na, and greater exposure to irradiance in the D. dacrydioides canopy compared with P. totara. Our findings support earlier observations that D. dacrydioides is more adapted to sites with poor drainage. In contrast, the high retention of leaf area and maintaining low rates of transpiration by P. totara, resulting in higher water-use efficiency, is an adaptive response to survival in dry conditions. Our findings show that physiological adjustments for two species adapted to different environments led to similar canopy photosynthesis rates when the trees were grown in the same conditions. We demonstrated consistency between whole-tree and more intensive shoot-scale measurements, confirming that integrated approaches are appropriate for comparative estimates of carbon uptake in stands with different species.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141727892","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}
Pub Date : 2024-08-03DOI: 10.1093/treephys/tpae088
Deliane Penha, Mauro Brum, Luciana F Alves, Tomas F Domingues, Anderson Meneses, Rardiles Branches, Natalia Restrepo-Coupe, Rafael S Oliveira, José Mauro S Moura, Pedro A C L Aurélio Pequeno, Neill Prohaska, Scott R Saleska
Increases in hydrological extremes, including drought, are expected for Amazon forests. A fundamental challenge for predicting forest responses lies in identifying ecological strategies which underlie such responses. Characterization of species-specific hydraulic strategies for regulating water-use, thought to be arrayed along an 'isohydric-anisohydric' spectrum, is a widely used approach. However, recent studies have questioned the usefulness of this classification scheme, because its metrics are strongly influenced by environments, and hence can lead to divergent classifications even within the same species. Here, we propose an alternative approach positing that individual hydraulic regulation strategies emerge from the interaction of environments with traits. Specifically, we hypothesize that the vertical forest profile represents a key gradient in drought-related environments (atmospheric vapor pressure deficit, soil water availability) that drives divergent tree water-use strategies for coordinated regulation of stomatal conductance (gs) and leaf water potentials (ΨL) with tree rooting depth, a proxy for water availability. Testing this hypothesis in a seasonal eastern Amazon forest in Brazil, we found that hydraulic strategies indeed depend on height-associated environments. Upper canopy trees, experiencing high vapor pressure deficit (VPD), but stable soil water access through deep rooting, exhibited isohydric strategies, defined by little seasonal change in the diurnal pattern of gs and steady seasonal minimum ΨL. In contrast, understory trees, exposed to less variable VPD but highly variable soil water availability, exhibited anisohydric strategies, with fluctuations in diurnal gs that increased in the dry season along with increasing variation in ΨL. Our finding that canopy height structures the coordination between drought-related environmental stressors and hydraulic traits provides a basis for preserving the applicability of the isohydric-to-anisohydric spectrum, which we show here may consistently emerge from environmental context. Our work highlights the importance of understanding how environmental heterogeneity structures forest responses to climate change, providing a mechanistic basis for improving models of tropical ecosystems.
{"title":"Preserving isohydricity: vertical environmental variability explains Amazon forest water-use strategies.","authors":"Deliane Penha, Mauro Brum, Luciana F Alves, Tomas F Domingues, Anderson Meneses, Rardiles Branches, Natalia Restrepo-Coupe, Rafael S Oliveira, José Mauro S Moura, Pedro A C L Aurélio Pequeno, Neill Prohaska, Scott R Saleska","doi":"10.1093/treephys/tpae088","DOIUrl":"10.1093/treephys/tpae088","url":null,"abstract":"<p><p>Increases in hydrological extremes, including drought, are expected for Amazon forests. A fundamental challenge for predicting forest responses lies in identifying ecological strategies which underlie such responses. Characterization of species-specific hydraulic strategies for regulating water-use, thought to be arrayed along an 'isohydric-anisohydric' spectrum, is a widely used approach. However, recent studies have questioned the usefulness of this classification scheme, because its metrics are strongly influenced by environments, and hence can lead to divergent classifications even within the same species. Here, we propose an alternative approach positing that individual hydraulic regulation strategies emerge from the interaction of environments with traits. Specifically, we hypothesize that the vertical forest profile represents a key gradient in drought-related environments (atmospheric vapor pressure deficit, soil water availability) that drives divergent tree water-use strategies for coordinated regulation of stomatal conductance (gs) and leaf water potentials (ΨL) with tree rooting depth, a proxy for water availability. Testing this hypothesis in a seasonal eastern Amazon forest in Brazil, we found that hydraulic strategies indeed depend on height-associated environments. Upper canopy trees, experiencing high vapor pressure deficit (VPD), but stable soil water access through deep rooting, exhibited isohydric strategies, defined by little seasonal change in the diurnal pattern of gs and steady seasonal minimum ΨL. In contrast, understory trees, exposed to less variable VPD but highly variable soil water availability, exhibited anisohydric strategies, with fluctuations in diurnal gs that increased in the dry season along with increasing variation in ΨL. Our finding that canopy height structures the coordination between drought-related environmental stressors and hydraulic traits provides a basis for preserving the applicability of the isohydric-to-anisohydric spectrum, which we show here may consistently emerge from environmental context. Our work highlights the importance of understanding how environmental heterogeneity structures forest responses to climate change, providing a mechanistic basis for improving models of tropical ecosystems.</p>","PeriodicalId":23286,"journal":{"name":"Tree physiology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141749142","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}