BEIJING, Dec 23 (Xinhua/APP): Researchers have disclosed that the photosynthesis of subtropical woody species is closely related to the water transport efficiency of the leaf vein system.
Leaf vein systems, or leaf xylem, contain vascular tissue that distributes water and nutrients to various parts of leaves.
Terrestrial plants need to consume massive amounts of water in order to absorb carbon dioxide through stomata. And the process of photosynthesis relies on the water transported to leaves.
Thus leaf gas exchange traits, like photosynthesis, are closely related to leaf water transport efficiency.
The researchers studied 33 woody species from subtropical monsoon evergreen broad-leaved forests, and measured plant leaf water transport efficiency and gas exchange traits, according to their recent study published in Tree Physiology.
In the study, leaf hydraulic conductance was divided into two components: leaf hydraulic conductance inside and outside the xylem.
The researchers found that the leaf hydraulic conductance inside the xylem was closely related to stomatal conductance and photosynthetic rate across species.
By contrast, the correlations between the leaf hydraulic conductance outside the xylem and stomatal conductance were substantially weaker.
This highlighted the possibility that water transport efficiency within leaf xylem, rather than that of leaf tissues outside the xylem, determined the stomatal conductance and photosynthetic capacity across species.