scholarly journals Hydraulic safety margin of 17 co-occurring woody plants in a seasonal rain forest in Guangxi’s Southwest karst landscape, China

2019 ◽  
Vol 43 (3) ◽  
pp. 227-237
Author(s):  
Feng-Sen TAN ◽  
Hui-Qing SONG ◽  
Zhong-Guo LI ◽  
Qi-Wei ZHANG ◽  
Shi-Dan ZHU ◽  
...  
Keyword(s):  
Rain Forest ◽  
Woody Plants ◽  
Safety Margin ◽  
Karst Landscape ◽  
Hydraulic Safety ◽  
Hydraulic Safety Margin

scholarly journals Leaf hydraulic safety margin and safety–efficiency trade-off across angiosperm woody species

2020 ◽  
Vol 16 (11) ◽  
pp. 20200456
Author(s):  
Chao-Long Yan ◽  
Ming-Yuan Ni ◽  
Kun-Fang Cao ◽  
Shi-Dan Zhu
Keyword(s):  
Water Potential ◽  
Global Analysis ◽  
Safety Margin ◽  
Woody Species ◽  
Hydraulic Conductance ◽  
Plant Distribution ◽  
Mean Annual Precipitation ◽  
Leaf Hydraulic Conductance ◽  
Hydraulic Safety ◽  
Hydraulic Safety Margin

Leaf hydraulic conductance and the vulnerability to water deficits have profound effects on plant distribution and mortality. In this study, we compiled a leaf hydraulic trait dataset with 311 species-at-site combinations from biomes worldwide. These traits included maximum leaf hydraulic conductance ( K leaf ), water potential at 50% loss of K leaf (P50 leaf ), and minimum leaf water potential ( Ψ min ). Leaf hydraulic safety margin (HSM leaf ) was calculated as the difference between Ψ min and P50 leaf . Our results indicated that 70% of the studied species had a narrow HSM leaf (less than 1 MPa), which was consistent with the global pattern of stem hydraulic safety margin. There was a positive relationship between HSM leaf and aridity index (the ratio of mean annual precipitation to potential evapotranspiration), as species from humid sites tended to have larger HSM leaf . We found a significant relationship between K leaf and P50 leaf across global angiosperm woody species and within each of the different plant groups. This global analysis of leaf hydraulic traits improves our understanding of plant hydraulic response to environmental change.

The legacy of water deficit on populations having experienced negative hydraulic safety margin

2017 ◽  
Vol 27 (3) ◽  
pp. 346-356 ◽  
Author(s):  
Marta Benito Garzón ◽  
Noelia González Muñoz ◽  
Jean-Pierre Wigneron ◽  
Christophe Moisy ◽  
Juan Fernández-Manjarrés ◽  
...  
Keyword(s):  
Water Deficit ◽  
Safety Margin ◽  
Hydraulic Safety ◽  
Hydraulic Safety Margin

Large scale assessment of post-drought climate sensitivity of tree-growth

2021 ◽  
Author(s):  
Christopher Leifsson ◽  
Allan Buras ◽  
Anja Rammig ◽  
Christian Zang
Keyword(s):  
Climate Sensitivity ◽  
Tree Growth ◽  
Secondary Growth ◽  
Safety Margin ◽  
Ring Width ◽  
High Plasticity ◽  
Legacy Effect ◽  
Tree Ring Data ◽  
Hydraulic Safety ◽  
Hydraulic Safety Margin

<p>Hotter droughts will have an increasingly influential role in shaping forest ecosystems in the future. Risks include decreases in species richness, altered species distributions, forest dieback and changed function as carbon sink. A common method to study the impacts of droughts on forests is the quantification of reductions in biomass productivity via secondary growth – approximated by ring-width measurements –, including duration until growth rates return to pre-drought levels, so-called legacy periods. However, while these metrics are practical and relatively easy to measure, the underlying governing mechanisms are not, and thus poorly understood. Consequently, it is uncertain if drought-induced reductions in secondary growth are due to corresponding decreases in total physiological function or high plasticity, and if recovery times are due to lasting damage or adaptation with more carbon allocated to drought-mitigating structures.</p><p>The principle of the most limiting factor for tree-growth can be used to track temporal variations in climate-growth relationships. Similarly, the considerable strain hotter drought constitutes for tree-growth, and the need to repair damaged structures or alter carbon allocation, may imply temporary climate sensitivity deviations during legacy periods. Identifying their existence and quantifying subsequent differences in these deviations can help to shed light on strategies used by trees to respond to droughts.</p><p>Here, we detect and quantify deviations in climate-growth relationships during hotter drought legacy periods and assess how they differ according to clade (angiosperms – gymnosperms), site aridity and hydraulic safety margin. We do this by applying a linear mixed model on all ring-width indices (RWI) in the global-scale International Tree-Ring Data Bank (ITRDB) which exhibit a positive correlation with Standardized Precipitation-Evapotranspiration Index (SPEI). We apply a combined climatological and ecological definition for drought events and use site-dependent SPEI time-scales to allow for specific climate dependencies.</p><p>Results show heterogeneous post-drought climate sensitivity deviations, which are broadly categorized in three groups: 1) angiosperms growing in arid sites become increasingly sensitive to climate for 2 – 4 years; 2) angiosperms in mesic sites and or with high hydraulic safety margin show abrupt and complete disruption of the climate-growth relationship for the first year after droughts, which turn into a decrease in climate sensitivity for an additional 1 – 3 years; 3) gymnosperms in arid sites become less sensitive to climate for 2 – 4 years, although without the abrupt disruption seen in group 2. We discuss these results and their implications in an ecophysiological context, including future research avenues.</p><p>In conclusion, the results clearly show a functional legacy effect that is not detected through measurements of reductions in biomass accumulation alone, hinting at differential strategies employed by trees to cope with hotter droughts. This is a first step towards a better understanding of the mechanisms underlying hotter drought legacies which may help to improve ecosystem models and better predict how trees will respond to drought in a warming future climate.</p>

Coordination between leaf biomechanical resistance and hydraulic safety across 30 subtropical woody species

2021 ◽  
Author(s):  
Yong-Qiang Wang ◽  
Ming-Yuan Ni ◽  
Wen-Hao Zeng ◽  
Dong-Liu Huang ◽  
Wei Xiang ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Linear Regression Analysis ◽  
Safety Margin ◽  
Woody Species ◽  
Hydraulic Conductance ◽  
Evergreen Broadleaved Forest ◽  
Functional Correlation ◽  
Hydraulic Safety ◽  
Hydraulic Safety Margin

Abstract Background and Aims Leaf biomechanical resistance protects leaves from biotic and abiotic damage. Previous studies have revealed that enhancing leaf biomechanical resistance is costly for plant species and leads to an increase in leaf drought tolerance. We thus predicted that there is a functional correlation between leaf hydraulic safety and biomechanical characteristics. Methods We measured leaf morphological and anatomical traits, pressure–volume parameters, maximum leaf hydraulic conductance (Kleaf-max), leaf water potential at 50% loss of hydraulic conductance (P50leaf), leaf hydraulic safety margin (SMleaf), and leaf force to tear (Ft) and punch (Fp) of 30 co-occurring woody species in a subtropical evergreen broadleaved forest. Linear regression analysis was performed to examine the relationships between biomechanical resistance and other leaf hydraulic traits. Key Results We found that higher Ft and Fp values were significantly associated with a lower (more negative) P50leaf and a larger SMleaf, thereby confirming the correlation between leaf biomechanical resistance and hydraulic safety. However, leaf biomechanical resistance showed no correlation with Kleaf-max, although it was significantly and negatively correlated with leaf outside-xylem hydraulic conductance. In addition, we also found that there was a significant correlation between biomechanical resistance and the modulus of elasticity by excluding an outlier. Conclusions The findings of this study reveal leaf biomechanical-hydraulic safety correlation in subtropical woody species.

scholarly journals Diversity of functional traits of fleshy fruits in a species-rich Atlantic rain forest

2011 ◽  
Vol 11 (1) ◽  
pp. 181-193 ◽  
Author(s):  
Mauro Galetti ◽  
Marco Aurélio Pizo ◽  
Leonor Patrícia Cerdeira Morellato
Keyword(s):  
Rain Forest ◽  
Woody Plants ◽  
Atlantic Rain Forest ◽  
Fruit Traits ◽  
Fruit Morphology ◽  
Se Brazil ◽  
Common Strategy ◽  
Tropical Woody Plants ◽  
Plant Families ◽  
Chemical Traits

Production of vertebrate-dispersed fruits is the most common strategy of tropical woody plants to disperse their seeds. Few studies have documented community-wide variation of fruit morphology and chemistry of vertebrate-dispersed fruits in species-rich tropical communities. We examined the functional diversity of fruit morphological and chemical traits of 186 species representing 57 plant families in an undisturbed lowland plant community in the Atlantic rain forest of SE, Brazil. We were particularly interested in associating morphological and chemical fruit traits to their main seed dispersers, either birds, mammals or 'mixed' (i.e. fruits eaten by birds and mammals). The morphological and chemical traits of fruits at the study site generally resemble the patterns observed in fruits worldwide. Bird fruits tend to be smaller than mammal fruits, being colored black or red, whereas mammal fruits are often yellow or green. Mammal fruits are more variable than bird fruits in relation to morphological traits, while the reverse is true for chemical traits. Mixed fruits resemble bird fruits in the patterns of variation of morphological and chemical traits, suggesting that they are primarily bird-dispersed fruits that are also exploited by mammals. Mixed fruits are common in tropical forests, and represent an excellent opportunity to contrast the effectiveness of different functional groups of frugivores dispersing the same plant species.

The hydraulic architecture of Eucalyptus trees growing across a gradient of depth-to-groundwater

2015 ◽  
Vol 42 (9) ◽  
pp. 888 ◽  
Author(s):  
Sepideh Zolfaghar ◽  
Randol Villalobos-Vega ◽  
Melanie Zeppel ◽  
Derek Eamus
Keyword(s):  
Hydraulic Conductivity ◽  
Leaf Area ◽  
Water Availability ◽  
Safety Margin ◽  
Hydraulic Architecture ◽  
Sapwood Area ◽  
Huber Value ◽  
Xylem Vulnerability ◽  
Safety Margins ◽  
Hydraulic Safety

Heterogeneity in water availability acts as an important driver of variation in plant structure and function. Changes in hydraulic architecture represent a key mechanism by which adaptation to changes in water availability can be expressed in plants. The aim of this study was to investigate whether differences in depth-to-groundwater influence the hydraulic architecture of Eucalyptus trees in remnant woodlands within mesic environments. Hydraulic architecture of trees was examined in winter and summer by measuring the following traits: Huber value (HV: the ratio between sapwood area and leaf area), branch hydraulic conductivity (leaf and sapwood area specific), sapwood density, xylem vulnerability (P50 and Pe) and hydraulic safety margins across four sites where depth-to-groundwater ranged from 2.4 to 37.5 m. Huber value increased significantly as depth-to-groundwater increased. Neither sapwood density nor branch hydraulic conductivity (sapwood and leaf area specific) varied significantly across sites. Xylem vulnerability to embolism (represented by P50 and Pe) in both seasons was significantly and negatively correlated with depth-to-groundwater. Hydraulic safety margins increased with increasing depth-to-groundwater and therefore trees growing at sites with deeper water tables were less sensitive to drought induced embolism. These results showed plasticity in some, but not all, hydraulic traits (as reflected in HV, P50, Pe and hydraulic safety margin) in response to increase in depth-to-groundwater in a mesic environment.

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