Leaf Thickness and Water Deficit in Plants: A Tool for Field Studies

Búrquez, A. 1987. Leaf thickness and water deficit in plants: a tool for field studies.—J. exp. Bot. 38: 109–114. A technique for estimating plant water deficits using a relatively inexpensive micrometer to measure leaf thickness was developed. A strong correlation was found between leaf thickness and relative water content (RWC) in Brassica napus, Mirabilis jalapa, Phaseolus vulgaris and Impatiens parviflora. Although leaf thickness at a given RWC varied between plants, it increased linearly with leaf RWC, the rate of change being similar in leaves of plants of the same age and species. Due to this relationship, the construction of a pressure-volume curve makes possible the estimation of leaf water potential. In this case a calibration curve is needed for each population studied or, for the highest accuracy, for each individual. The technique is particularly useful in field conditions where other techniques are not reliable because of difficulties in controlling temperature and where non-destructive measurements are required.