Nutrio‐Physiological Evaluation of the Polyethylene Glycol Test of Cell Membrane Stability in Maize

Abstract

Cell membrane stability (CMS) of maize (Zea mays L.) was measured by the polyethylene glycol (PEG) test and compared with the nutrio‐physiological characteristics to examine the relationship of plant processes involved in differential ion leakage. Two pot experiments were conducted in the glasshouse under three soil moisture levels (MPa 0 to −0.05, −0.3 to −0.9, and −1.2 to −1.5) using three cultivars (P‐3358, G‐4578, and FFR‐677) of maize. Leaf water potential, osmotic potential, stomatal resistance, cuticular resistance, excised‐leaf water retention capability, degree of leaf rolling, total plant weight, and total root length as well as the CMS by the PEG test were measured when the plants were 60 d old. Nutrient concentrations in leaf tissues, cell sap, and cell leachate were analysed. Cell membrane stability measured by the PEG test was well related to the other physiological measurements. It was highly or very highly correlated with leaf water potential (r = −0.869**), (significant at P = 0.01) osmotic potential (r = −0.946**), excised‐leaf water retention capability (r = 0.767**), K concentration in leaf tissues (r = 0.757*) (significant at P = 0.05) and cell sap (r = 0.690*), and the degree of leaf rolling. Cell membrane stability appears to be influenced by osmotic potential of leaf tissues. Sugar and K were the major osmotic contributors. In conclusion, we find the PEG test to be a useful measure of drought tolerance in maize.