K+ starvation inhibits water-stress-induced stomatal closure via ethylene synthesis in sunflower plants.

The effect of water stress on stomatal closure in sunflower plants has been found to be dependent on K(+) nutrient status. When plants with different internal K(+) content were subjected to a water-stress period, stomatal conductance was reduced more markedly in plants with an adequate K(+) supply than in K(+)-starved plants. K(+) starvation promoted the production of ethylene by detached leaves, as well as by the shoot of whole plants.