The Experts below are selected from a list of 32139 Experts worldwide ranked by ideXlab platform
Markus Nolf - One of the best experts on this subject based on the ideXlab platform.
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stem and leaf hydraulic properties are finely coordinated in three tropical rain forest tree species
Plant Cell and Environment, 2015Co-Authors: Markus Nolf, Danielle Creek, Remko A Duursma, Joseph A M Holtum, Stefan Mayr, Brendan ChoatAbstract:Coordination of stem and leaf hydraulic traits allows terrestrial plants to maintain safe water status under limited water supply. Tropical rain forests, one of the world's most productive biomes, are vulnerable to drought and potentially threatened by increased aridity due to global climate change. However, the relationship of stem and leaf traits within the plant hydraulic continuum remains understudied, particularly in tropical species. We studied within-plant hydraulic coordination between stems and leaves in three tropical lowland rain forest tree species by analyses of hydraulic vulnerability [hydraulic methods and ultrasonic emission (UE) analysis], pressure-volume relations and in situ pre-dawn and midday water potentials (Ψ). We found finely coordinated stem and leaf hydraulic features, with a strategy of sacrificing leaves in favour of stems. Fifty percent of hydraulic conductivity (P50) was lost at −2.1 to −3.1 MPa in stems and at −1.7 to −2.2 MPa in leaves. UE analysis corresponded to hydraulic measurements. Safety margins (leaf P50 – stem P50) were very narrow at −0.4 to −1.4 MPa. Pressure-volume analysis and in situ Ψ indicated safe water status in stems but risk of hydraulic failure in leaves. Our study shows that stem and leaf Hydraulics were finely tuned to avoid embolism formation in the xylem.
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stem and leaf hydraulic properties are finely coordinated in three tropical rain forest tree species
Plant Cell and Environment, 2015Co-Authors: Markus Nolf, Danielle Creek, Remko A Duursma, Joseph A M Holtum, Stefan Mayr, Brendan ChoatAbstract:Coordination of stem and leaf hydraulic traits allows terrestrial plants to maintain safe water status under limited water supply. Tropical rain forests, one of the world's most productive biomes, are vulnerable to drought and potentially threatened by increased aridity due to global climate change. However, the relationship of stem and leaf traits within the plant hydraulic continuum remains understudied, particularly in tropical species. We studied within-plant hydraulic coordination between stems and leaves in three tropical lowland rain forest tree species by analyses of hydraulic vulnerability [hydraulic methods and ultrasonic emission (UE) analysis], pressure-volume relations and in situ pre-dawn and midday water potentials (Ψ). We found finely coordinated stem and leaf hydraulic features, with a strategy of sacrificing leaves in favour of stems. Fifty percent of hydraulic conductivity (P50) was lost at −2.1 to −3.1 MPa in stems and at −1.7 to −2.2 MPa in leaves. UE analysis corresponded to hydraulic measurements. Safety margins (leaf P50 – stem P50) were very narrow at −0.4 to −1.4 MPa. Pressure-volume analysis and in situ Ψ indicated safe water status in stems but risk of hydraulic failure in leaves. Our study shows that stem and leaf Hydraulics were finely tuned to avoid embolism formation in the xylem.
Brendan Choat - One of the best experts on this subject based on the ideXlab platform.
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stem and leaf hydraulic properties are finely coordinated in three tropical rain forest tree species
Plant Cell and Environment, 2015Co-Authors: Markus Nolf, Danielle Creek, Remko A Duursma, Joseph A M Holtum, Stefan Mayr, Brendan ChoatAbstract:Coordination of stem and leaf hydraulic traits allows terrestrial plants to maintain safe water status under limited water supply. Tropical rain forests, one of the world's most productive biomes, are vulnerable to drought and potentially threatened by increased aridity due to global climate change. However, the relationship of stem and leaf traits within the plant hydraulic continuum remains understudied, particularly in tropical species. We studied within-plant hydraulic coordination between stems and leaves in three tropical lowland rain forest tree species by analyses of hydraulic vulnerability [hydraulic methods and ultrasonic emission (UE) analysis], pressure-volume relations and in situ pre-dawn and midday water potentials (Ψ). We found finely coordinated stem and leaf hydraulic features, with a strategy of sacrificing leaves in favour of stems. Fifty percent of hydraulic conductivity (P50) was lost at −2.1 to −3.1 MPa in stems and at −1.7 to −2.2 MPa in leaves. UE analysis corresponded to hydraulic measurements. Safety margins (leaf P50 – stem P50) were very narrow at −0.4 to −1.4 MPa. Pressure-volume analysis and in situ Ψ indicated safe water status in stems but risk of hydraulic failure in leaves. Our study shows that stem and leaf Hydraulics were finely tuned to avoid embolism formation in the xylem.
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stem and leaf hydraulic properties are finely coordinated in three tropical rain forest tree species
Plant Cell and Environment, 2015Co-Authors: Markus Nolf, Danielle Creek, Remko A Duursma, Joseph A M Holtum, Stefan Mayr, Brendan ChoatAbstract:Coordination of stem and leaf hydraulic traits allows terrestrial plants to maintain safe water status under limited water supply. Tropical rain forests, one of the world's most productive biomes, are vulnerable to drought and potentially threatened by increased aridity due to global climate change. However, the relationship of stem and leaf traits within the plant hydraulic continuum remains understudied, particularly in tropical species. We studied within-plant hydraulic coordination between stems and leaves in three tropical lowland rain forest tree species by analyses of hydraulic vulnerability [hydraulic methods and ultrasonic emission (UE) analysis], pressure-volume relations and in situ pre-dawn and midday water potentials (Ψ). We found finely coordinated stem and leaf hydraulic features, with a strategy of sacrificing leaves in favour of stems. Fifty percent of hydraulic conductivity (P50) was lost at −2.1 to −3.1 MPa in stems and at −1.7 to −2.2 MPa in leaves. UE analysis corresponded to hydraulic measurements. Safety margins (leaf P50 – stem P50) were very narrow at −0.4 to −1.4 MPa. Pressure-volume analysis and in situ Ψ indicated safe water status in stems but risk of hydraulic failure in leaves. Our study shows that stem and leaf Hydraulics were finely tuned to avoid embolism formation in the xylem.
Guangyou Hao - One of the best experts on this subject based on the ideXlab platform.
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contrasts in xylem Hydraulics and water use underlie the sorting of different sand fixing shrub species to early and late stages of dune stabilization
Forest Ecology and Management, 2020Co-Authors: Xuewei Gong, Guillermo Goldstein, Jingjing Guo, Deming Jiang, Fabian G Scholz, Sandra J Bucci, Guangyou HaoAbstract:Abstract Dominating sand-fixing shrubs play crucial roles in the stabilization and rehabilitation of sand dunes. Different sand-fixing shrub species often separate along the temporal-spatial environmental gradient during the sand dune stabilization process; however, the physiological mechanisms underlying such a separation remain poorly understood, which limits our ability to identify the causes of land desertification and the cruxes of rehabilitation. We investigated xylem Hydraulics and water use characteristics of four important shrub species used for sand dune fixation projects in northern China that show distinct preferences to different stages of dune stabilization, i.e. two species succeed in active dunes and the other two in fixed dunes. The major aim was to examine the roles of xylem Hydraulics, water use and the coordination of these two aspects in determining the habitat preferences of sand-fixing shrubs along the process of dune stabilization in water-limited environments. The two active-dune species consistently exhibited higher stem hydraulic conductivity but lower resistance to drought-induced xylem embolism than the two fixed-dune species, which reflects contrasting requirements to shrub hydraulic functionality in sand dunes of the two successional stages that differ substantially in soil water regimes. In coordination with contrasts in Hydraulics, they also diverged clearly in water use strategies with the fixed-dune shrubs showing more conservative water use. Our results highlight the critical roles that Hydraulics and water utilization play in determining the adaptation of dominating sand-fixing shrub species to their respective environments shaped by the plant-soil interactions during sand dune vegetation development.
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the interaction between nonstructural carbohydrate reserves and xylem Hydraulics in korean pine trees across an altitudinal gradient
Tree Physiology, 2018Co-Authors: Aiying Wang, Miao Wang, Shijie Han, Junhui Zhang, Xiaohan Yin, Lidong Fang, Da Yang, Guangyou HaoAbstract:Nonstructural carbohydrates (NSC) have been proposed to play an important role in maintaining the hydraulic integrity of trees, particularly in environments with high risks of embolism formation, but knowledge about the interaction between NSC reserves and xylem Hydraulics is still very limited. We studied the variation of NSC reserves and hydraulic traits in Pinus koraiensis Sieb. et Zucc. (Korean pine) in March and June across a relatively large altitudinal gradient in Changbai Mountain of Northeast China. One of the major aims was to investigate the potential role NSC plays in maintaining hydraulic integrity of overwintering stems in facing freezing-induced embolism. Consistent with our hypotheses, substantial variations in both NSC contents and hydraulic traits were observed across altitudes and between the two seasons. In March, when relatively high degrees of winter embolism exist, the percentage loss of conductivity (PLC) showed an exponential increase with altitude. Most notably, positive correlations between branch and trunk soluble sugar content and PLC (P = 0.053 and 0.006) were observed across altitudes during this period. These correlations could indicate that more soluble sugars are required for maintaining stem hydraulic integrity over the winter by resisting or refilling freezing-induced embolism in harsher environments, although more work is needed to establish a direct causal relationship between NSC dynamics and xylem Hydraulics. If the correlation is indeed directly associated with varying demands for maintaining hydraulic integrity across environmental gradients, greater carbon demands may compromise tree growth under conditions of higher risk of winter embolism leading to a trade-off between competitiveness and stress resistance, which may be at least partially responsible for the lower dominance of Korean pine trees at higher altitudes.
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coordinated responses of plant hydraulic architecture with the reduction of stomatal conductance under elevated co2 concentration
Tree Physiology, 2018Co-Authors: Michele N Holbrook, Guangyou Hao, Maciej A Zwieniecki, Vincent P Gutschick, Hormoz BassiriradAbstract:Stomatal conductance (gs) generally decreases under elevated CO2 concentration (eCO2) and its sensitivity varies widely among species, yet the underlying mechanisms for these observed patterns are not totally clear. Understanding these underlying mechanisms, however, is critical for addressing problems regarding plant-environment interactions in a changing climate. We examined gs, water transport efficiency of different components along the whole-plant hydraulic system and allometric scaling in seedlings of six tree species grown under ambient and eCO2 treatments (400 and 600 ppm, respectively). Growth under eCO2 caused gs to decrease in all species but to highly variable extents, ranging from 13% (Populus tremuloides Michx.) to 46% (Gymnocladus dioicus (L.)). Accompanying this significant decrease in gs, substantial changes in plant hydraulic architecture occurred, with root hydraulic conductance expressed both on leaf area and root mass bases overall exhibiting significant decreases, while stem and leaf hydraulic efficiency either increased or showed no consistent pattern of change. Moreover, significant changes in allometry in response to eCO2 affected the whole-plant water supply and demand relations. The interspecific variation in gs response among species was not correlated with relative changes in stem and leaf hydraulic conductance but was most strongly correlated with the relative change in the allometric scaling between roots and leaves, and to a lesser extent with the intrinsic root hydraulic conductance of the species. The results underscore that allometric adjustments between root and leaf play a key role in determining the interspecific sensitivity of gs responses to eCO2. Plant Hydraulics and their associated allometric scaling are important changes accompanying gs responses to eCO2 and may play important roles in mediating the interspecific variations of leaf gas exchange responses, which suggests that mechanistic investigations regarding plant responses to eCO2 need to integrate characteristics of Hydraulics and allometric scaling in the future.
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divergences in hydraulic architecture form an important basis for niche differentiation between diploid and polyploid betula species in ne china
Tree Physiology, 2017Co-Authors: Weiwei Zhang, Yongjiang Zhang, Jia Song, Miao Wang, Yanyan Liu, Michele N Holbrook, Guangyou HaoAbstract:Habitat differentiation between polyploid and diploid plants are frequently observed, with polyploids usually occupying more stressed environments. In woody plants, polyploidization can greatly affect wood characteristics but knowledge of its influences on xylem Hydraulics is scarce. The four Betula species in NE China, representing two diploids and two polyploids with obvious habitat differentiation, provide an exceptional study system for investigating the impact of polyploidization on environmental adaptation of trees from the point view of xylem Hydraulics. To test the hypothesis that changes in hydraulic architecture play an important role in determining their niche differentiation, we measured wood structural traits at both the tissue and pit levels and quantified xylem water transport efficiency and safety in these species. The two polyploids had significantly larger hydraulic weighted mean vessel diameters than the two diploids (45.1 and 45.5 vs 25.9 and 24.5 μm) although the polyploids are occupying more stressed environments. As indicated by more negative water potentials corresponding to 50% loss of stem hydraulic conductivities, the two polyploids exhibited significantly higher resistance to drought-induced embolism than the two diploids (-5.23 and -5.05 vs -3.86 and -3.13 MPa) despite their larger vessel diameters. This seeming discrepancy is reconciled by distinct characteristics favoring greater embolism resistance at the pit level in the two polyploid species. Our results showed clearly that the two polyploid species have remarkably different pit-level anatomical traits favoring greater hydraulic safety than their congeneric diploid species, which have likely contributed to the abundance of polyploid birches in more stressed habitats; however, less porous inter-conduit pits together with a reduced leaf to sapwood area may have compromised their competitiveness under more favorable conditions. Contrasts in hydraulic architecture between diploid and polyploid Betula species suggest an important functional basis for their clear habitat differentiation along environmental gradients in Changbai Mountain of NE China.
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ecology of hemiepiphytism in fig species is based on evolutionary correlation of Hydraulics and carbon economy
Ecology, 2011Co-Authors: Guillermo Goldstein, Michele N Holbrook, Guangyou Hao, Aiying Wang, Lawren Sack, Zhihui Liu, Rhett D HarrisonAbstract:Woody hemiepiphytic species (Hs) are important components of tropical rain forests, and they have been hypothesized to differ from non-hemiepiphytic tree species (NHs) in adaptations relating to water relations and carbon economy; but few studies have been conducted comparing ecophysiological traits between the two growth forms especially in an evolutionary context. Using common-garden plants of the genus Ficus, functional traits related to plant Hydraulics and carbon economy were compared for seven NHs and seven Hs in their adult terrestrial ''tree-like'' growth phase. We used phylogenetically independent contrasts to test the hypothesis that differences in water availability selected for contrasting suites of traits in Hs and NHs, driving evolutionary correlations among functional traits including hydraulic conductivity and photosynthetic traits. Species of the two growth forms differed in functional traits; Hs had substantially lower xylem hydraulic conductivity and stomatal conductance, and higher instantaneous photosynthetic water use efficiency. Leaf morphological and structural traits also differed strikingly between the two growth forms. The Hs had significantly smaller leaves, higher leaf mass per area (LMA), and smaller xylem vessel lumen diameters. Across all the species, hydraulic conductivity was positively correlated with leaf gas exchange indicating high degrees of hydraulic-photosynthetic coordination. More importantly, these correlations were supported by correlations implemented on phylogenetic independent contrasts, suggesting that most trait correlations arose through repeated convergent evolution rather than as a result of chance events in the deep nodes of the lineage. Variation in xylem hydraulic conductivity was also centrally associated with a suite of other functional traits related to carbon economy and growth, such as LMA, water use efficiency, leaf nutrient concentration, and photosynthetic nutrient use efficiency, indicating important physiological constraints or trade-offs among functional traits. Shifts in this trait cluster apparently related to the adaptation to drought-prone canopy growth during the early life cycle of Hs and clearly affected ecophysiology of the later terrestrial stage of these species. Evolutionary flexibility in Hydraulics and associated traits might be one basis for the hyper- diversification of Ficus species in tropical rain forests.
Guillermo Goldstein - One of the best experts on this subject based on the ideXlab platform.
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contrasts in xylem Hydraulics and water use underlie the sorting of different sand fixing shrub species to early and late stages of dune stabilization
Forest Ecology and Management, 2020Co-Authors: Xuewei Gong, Guillermo Goldstein, Jingjing Guo, Deming Jiang, Fabian G Scholz, Sandra J Bucci, Guangyou HaoAbstract:Abstract Dominating sand-fixing shrubs play crucial roles in the stabilization and rehabilitation of sand dunes. Different sand-fixing shrub species often separate along the temporal-spatial environmental gradient during the sand dune stabilization process; however, the physiological mechanisms underlying such a separation remain poorly understood, which limits our ability to identify the causes of land desertification and the cruxes of rehabilitation. We investigated xylem Hydraulics and water use characteristics of four important shrub species used for sand dune fixation projects in northern China that show distinct preferences to different stages of dune stabilization, i.e. two species succeed in active dunes and the other two in fixed dunes. The major aim was to examine the roles of xylem Hydraulics, water use and the coordination of these two aspects in determining the habitat preferences of sand-fixing shrubs along the process of dune stabilization in water-limited environments. The two active-dune species consistently exhibited higher stem hydraulic conductivity but lower resistance to drought-induced xylem embolism than the two fixed-dune species, which reflects contrasting requirements to shrub hydraulic functionality in sand dunes of the two successional stages that differ substantially in soil water regimes. In coordination with contrasts in Hydraulics, they also diverged clearly in water use strategies with the fixed-dune shrubs showing more conservative water use. Our results highlight the critical roles that Hydraulics and water utilization play in determining the adaptation of dominating sand-fixing shrub species to their respective environments shaped by the plant-soil interactions during sand dune vegetation development.
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midday stomatal conductance is more related to stem rather than leaf water status in subtropical deciduous and evergreen broadleaf trees
Plant Cell and Environment, 2013Co-Authors: Yongjiang Zhang, Frederick C. Meinzer, Jinhua Qi, Guillermo GoldsteinAbstract:Midday depressions in stomatal conductance (gs) and pho- tosynthesis are common in plants.The aim of this study was to understand the hydraulic determinants of midday gs, the coordination between leaf and stem Hydraulics and whether regulation of midday gs differed between deciduous and evergreen broadleaf tree species in a subtropical cloud forest of Southwest (SW) China. We investigated leaf and stem Hydraulics, midday leaf and stem water potentials, as well as midday gs of co-occurring deciduous and ever- green tree species. Midday gs was correlated positively with midday stem water potential across both groups of species, but not with midday leaf water potential. Species with higher stem hydraulic conductivity and greater daily reliance on stem hydraulic capacitance were able to main- tain higher stem water potential and higher gs at midday. Deciduous species exhibited significantly higher stem hydraulic conductivity, greater reliance on stem capaci- tance, higher stem water potential and gs at midday than evergreen species. Our results suggest that midday gs is more associated with midday stem than with leaf water status, and that the functional significance of stomatal regulation in these broadleaf tree species is probably for preventing stem xylem dysfunction.
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ecology of hemiepiphytism in fig species is based on evolutionary correlation of Hydraulics and carbon economy
Ecology, 2011Co-Authors: Guillermo Goldstein, Michele N Holbrook, Guangyou Hao, Aiying Wang, Lawren Sack, Zhihui Liu, Rhett D HarrisonAbstract:Woody hemiepiphytic species (Hs) are important components of tropical rain forests, and they have been hypothesized to differ from non-hemiepiphytic tree species (NHs) in adaptations relating to water relations and carbon economy; but few studies have been conducted comparing ecophysiological traits between the two growth forms especially in an evolutionary context. Using common-garden plants of the genus Ficus, functional traits related to plant Hydraulics and carbon economy were compared for seven NHs and seven Hs in their adult terrestrial ''tree-like'' growth phase. We used phylogenetically independent contrasts to test the hypothesis that differences in water availability selected for contrasting suites of traits in Hs and NHs, driving evolutionary correlations among functional traits including hydraulic conductivity and photosynthetic traits. Species of the two growth forms differed in functional traits; Hs had substantially lower xylem hydraulic conductivity and stomatal conductance, and higher instantaneous photosynthetic water use efficiency. Leaf morphological and structural traits also differed strikingly between the two growth forms. The Hs had significantly smaller leaves, higher leaf mass per area (LMA), and smaller xylem vessel lumen diameters. Across all the species, hydraulic conductivity was positively correlated with leaf gas exchange indicating high degrees of hydraulic-photosynthetic coordination. More importantly, these correlations were supported by correlations implemented on phylogenetic independent contrasts, suggesting that most trait correlations arose through repeated convergent evolution rather than as a result of chance events in the deep nodes of the lineage. Variation in xylem hydraulic conductivity was also centrally associated with a suite of other functional traits related to carbon economy and growth, such as LMA, water use efficiency, leaf nutrient concentration, and photosynthetic nutrient use efficiency, indicating important physiological constraints or trade-offs among functional traits. Shifts in this trait cluster apparently related to the adaptation to drought-prone canopy growth during the early life cycle of Hs and clearly affected ecophysiology of the later terrestrial stage of these species. Evolutionary flexibility in Hydraulics and associated traits might be one basis for the hyper- diversification of Ficus species in tropical rain forests.
Remko A Duursma - One of the best experts on this subject based on the ideXlab platform.
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stem and leaf hydraulic properties are finely coordinated in three tropical rain forest tree species
Plant Cell and Environment, 2015Co-Authors: Markus Nolf, Danielle Creek, Remko A Duursma, Joseph A M Holtum, Stefan Mayr, Brendan ChoatAbstract:Coordination of stem and leaf hydraulic traits allows terrestrial plants to maintain safe water status under limited water supply. Tropical rain forests, one of the world's most productive biomes, are vulnerable to drought and potentially threatened by increased aridity due to global climate change. However, the relationship of stem and leaf traits within the plant hydraulic continuum remains understudied, particularly in tropical species. We studied within-plant hydraulic coordination between stems and leaves in three tropical lowland rain forest tree species by analyses of hydraulic vulnerability [hydraulic methods and ultrasonic emission (UE) analysis], pressure-volume relations and in situ pre-dawn and midday water potentials (Ψ). We found finely coordinated stem and leaf hydraulic features, with a strategy of sacrificing leaves in favour of stems. Fifty percent of hydraulic conductivity (P50) was lost at −2.1 to −3.1 MPa in stems and at −1.7 to −2.2 MPa in leaves. UE analysis corresponded to hydraulic measurements. Safety margins (leaf P50 – stem P50) were very narrow at −0.4 to −1.4 MPa. Pressure-volume analysis and in situ Ψ indicated safe water status in stems but risk of hydraulic failure in leaves. Our study shows that stem and leaf Hydraulics were finely tuned to avoid embolism formation in the xylem.
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stem and leaf hydraulic properties are finely coordinated in three tropical rain forest tree species
Plant Cell and Environment, 2015Co-Authors: Markus Nolf, Danielle Creek, Remko A Duursma, Joseph A M Holtum, Stefan Mayr, Brendan ChoatAbstract:Coordination of stem and leaf hydraulic traits allows terrestrial plants to maintain safe water status under limited water supply. Tropical rain forests, one of the world's most productive biomes, are vulnerable to drought and potentially threatened by increased aridity due to global climate change. However, the relationship of stem and leaf traits within the plant hydraulic continuum remains understudied, particularly in tropical species. We studied within-plant hydraulic coordination between stems and leaves in three tropical lowland rain forest tree species by analyses of hydraulic vulnerability [hydraulic methods and ultrasonic emission (UE) analysis], pressure-volume relations and in situ pre-dawn and midday water potentials (Ψ). We found finely coordinated stem and leaf hydraulic features, with a strategy of sacrificing leaves in favour of stems. Fifty percent of hydraulic conductivity (P50) was lost at −2.1 to −3.1 MPa in stems and at −1.7 to −2.2 MPa in leaves. UE analysis corresponded to hydraulic measurements. Safety margins (leaf P50 – stem P50) were very narrow at −0.4 to −1.4 MPa. Pressure-volume analysis and in situ Ψ indicated safe water status in stems but risk of hydraulic failure in leaves. Our study shows that stem and leaf Hydraulics were finely tuned to avoid embolism formation in the xylem.
