Water is one of the most limiting factors for terrestrial plant life. In dry conditions, hydraulic coordination of stems and leaves enables plants to maintain a safe water status and avoid hydraulic failure in the xylem. While such relationships have been shown for some tree species previously, little is known about hydraulic coordination in rainforest species which do not typically experience drought and represent a hydraulically understudied group of plants.

In our recent publication “Stem and leaf hydraulic properties are finely coordinated in three tropical rain forest tree species”, we studied plant hydraulics at the Daintree Rainforest Observatory in Far North Queensland and compared a number of hydraulic traits (including hydraulic vulnerability of stems and leaves, pressure-volume relations and in situ water potentials) in three tropical rain forest species.

We found that stems and leaves were finely coordinated towards embolism avoidance even in a wet rainforest environment. Despite narrow hydraulic safety margins between leaf and stem P₅₀, hydraulic failure in leaves would protect stems from extreme water potentials and embolism in case of drought.
Our findings provide evidence that even trees from humid environments operate near their hydraulic limits and may be threatened by increasing drought.

Citation: Nolf M., Creek D., Duursma R., Holtum J., Mayr S., Choat B. 2015. Stem and leaf hydraulic properties are finely coordinated in three tropical rain forest tree species. Plant, Cell and Environment. doi:10.1111/pce.12581

The full paper is available in Plant, Cell and Environment and can also be requested on Researchgate.