Pressure – volume curves and drought injury

Leaf hygrometers were used to establish pressure‐volume curves on detached leaves of four herbaceous species (Asarum europaeum, L., Hepatica nobilis, Mill., Phyteuma spicatum, L., Pulmonaria officialis, L.). Breakdown of leaf tissues due to drought injury was independently estimated. There was good agreement between the onset of visible symptoms and beginning deviations from the straight‐line portion of the pressure‐volume curve. Type I transformation of data (plots of water potential vs. reciprocal relative water content) is superior for recognizing deviating data points. The results are discussed in the context of pressure‐volume curve methodology; pressure‐volume curves are shown to provide a promising tool for estimating and displaying drought tolerance in plants.