Leaf turgor loss point is correlated with drought tolerance and leaf carbon economics traits

Leaf turgor loss point (pi(tlp)) indicates the capacity of a plant to maintain cell turgor pressure during dehydration, which has been proven to be strongly predictive of the plant response to drought. In this study, we compiled a data set of a pi(tlp) for 1752 woody plant individuals belonging to 389 species from nine major woody biomes in China, along with reduced sample size of hydraulic and leaf carbon economics data. We aimed to investigate the variation of pi(tlp) across biomes varying in water availability. We also tested two hypotheses: (i) pi(tlp) predicts leaf hydraulic safety margins and (ii) it is correlated with leaf carbon economics traits. Our results showed that there was a positive relationship between pi(tlp )and aridity index: biomes from humid regions had less negative values than those from arid regions. This supports the idea that pi(tlp )may reflect drought tolerance at the scale of woody biomes. As expected, pi(tlp) was significantly positively correlated with leaf hydraulic safety margins that varied significantly across biomes, indicating that this trait may be useful in modelling changes of forest components in response to increasing drought. Moreover, pi(tlp) was correlated with a suite of coordinated hydraulic and economics traits; therefore, it can be used to predict the position of a given species along the 'fast-slow' whole-plant economics spectrum. This study expands our understanding of the biological significance of pi(tlp )not only in drought tolerance, but also in the plant economics spectrum.