Studies on the interaction of growth regulators with potassium ions in some physiological processes in bean (Phaseolus vulgaris L.). III The effect of growth regulators on growth, chlorophyll level and transpiration depending on potassium concentration

Abstract

Leaf growth and chlorophyll level in GA₃-treated bean, and leaf growth and transpiration intensity in ABA-treated bean plants were studied at two potassium concentrations in the medium (1 and 3 mM KNO₃). The plants were grown on Hoagland's solution and growth regulators were applied to the shoot growth apexes. Both GA₃ and K⁺ ions were found to stimulate growth of primary leaves and increase their potassium amount. GA₃ contrary to K⁺ slightly decreased the potassium content in leaves Both factors reduced the chlorophyll content but did not affect the total chlorophyll amount in these organs Interaction between GA₃ and K⁺ ions was of additive nature. The effect of ABA and K⁺ ions on growth of both kinds of leaves and on the amount and content of potassium in them were antagonistic. The inhibitory effect of the hormone was stronger at higher potassium concentration in the medium. Either factor reduced transpiration intensity in leaves, however, the inhibitory effect of the growth regulator was stronger at lower potassium concentration. The potassium level modified both the physiological effect of the regulators and the sensitivity of bean particularly to ABA.