Cell Membrane Stability and Leaf Water Relations as Affected by Potassium Nutrition of Water-Stressed Maize

Abstract

A field experiment was conducted to investigate the effect of K nutrition under water stress conditions on cell membrane stability measured by the polyethylene glycol test, plant growth, internal plant water relations and solute and mineral concentrations in maize (Zea mays L.). Water-stressed plants showed greater adaptation to water deficits at higher K levels. Cell membrane stability increased, leaf water potential and osmotic potential decreased, turgor potential increased and stomatal resistance decreased with increasing K nutrition. Osmotic adjustment was evident and it may have been influenced by increased K+ concentrations in leaf tissues with increasing K nutrition. Higher leaf thickness and higher leaf water content were observed at higher K levels. Results suggested that higher supplies of K nutrition may increase plant production during periods of water stress.