Measurement of plant water status: Historical perspectives and current concerns

Abstract

The slow development of concepts and methods for evaluating plant water status is reviewed. These include visual symptoms such as wilting and leaf rolling, measurement of water content, osmotic potential, and total water potential. The best method depends on the objectives of the user, but none of the methods are very well correlated with the effects of water stress on enzyme-mediated processes. Although some investigators claim that relative water content is better correlated with physiological processes than water potential, the latter has the advantage of providing results in well recognized physical units that apply to both plant and soil water status.