Kinetics of shoot surface water uptake and its effects on leaf hydraulic conductance in Avicennia marina

There has been debate over the significance of shoot surface water uptake (SSWU) in plants. We hypothesized that this form of water uptake may lead to recovery of leaf hydraulic conductance lost through dehydration, and that dehydration itself may affect the conductance to SSWU.

We tested these hypotheses by tracking changes in leaf water potential through time in excised branches of the grey mangrove, Avicennia marina. Using pressure-volume data gathered from the same tree population, we estimated the volume of water absorbed through the leaf surface during SSWU, and the volume of water taken up through the petiole before and after SSWU. The method is a modified version of the rehydration-kinetics method (Brodribb and Holbrook, 2003). Full details are available at:

Fuenzalida, T.I., Bryant, C.J., Ovington, L.I., Yoon, H.‐J., Oliveira, R.S., Sack, L. and Ball, M.C. (2019), Shoot surface water uptake enables leaf hydraulic recovery in Avicennia marina. New Phytol, 224: 1504-1511. doi:10.1111/nph.16126

Results show a decline in the conductance to SSWU with rehydration time, but not with dehydration, and full recovery of leaf hydraulic conductance through SSWU.

This research was funded by the Australian Research Council through grant DP180102969: Top-down rehydration: the role of multiple water sources in maintaining hydraulic function of mangroves along gradients in salinity and aridity.