Branch water potential; a useful indicator of plant water potential in comparison to leaf water potential in canola

Abstract

The water potentials of canola branches and leaves were compared using a pressure chamber to determine whether they produced similar results. This study also investigated the magnitude of errors in the water status of canola resulting from re-cutting the branches, and the effects of delaying readings.

The use of branches containing pods or pods and flowers/buds gave very good correlation with leaves. As this is the area of greatest photosynthesis and transpiration from mid-flowering, it provides an easily obtainable source material close to the main growth areas to measure plant water potential. Storage of both leaves and stems before measurement is an acceptable procedure if a large number of samples are required to be completed or portable equipment is not available provided precautions are taken to prevent moisture loss. Re-cutting the branch leads to lower water potential and should be avoided.