ISSN 0371-0874, CN 31-1352/Q

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Effects of osmotic stress on K~(+) uptake in sorghum roots

Yi Yin, Tang Zhangcheng

Shanghai Institute of Plant Physiology,The Chinese Academy of Sciences.Shanghai 200032

Abstract

Low K~(+) sorghum plants were cultured in 0.5 mmol L~(-1) CaSO_(4) solution.The low K~(+) roots of these plants had two K~(+) uptake systems: a high-affinity component and a linearlow-affinity component. A decrease of the external osmotic potential, caused by PEG-1000 solution,simulated K~(+) accumulation completed by a new transport system with appearant K_(m) and V_(max) values of 18 #mu#mol L~(-1) and 49.6 #mu#molg~(-1)DWh~(-1),respectively.The relationship between H~(+) efflux and K~(+) accumulation showed that the high-affinity system was driven directly by ATP,while the low-affinity system was coupled to H~(+) extrusion.The inhibition of this process by cycloheximide,indicated that the high-affinity component was formed through de novo synthesis under PEG-1000 stress.Therefore,it is suggested that osmotic stress can induce the formation of a high-affinity K~(+) transport system.

Key words: Osmotic stress;Sorghum roots;K~(+) uptake;H~(+)secretion

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Citing This Article:

Yi Yin, Tang Zhangcheng. Effects of osmotic stress on K~(+) uptake in sorghum roots. Acta Physiol Sin 1996; 48 (2): (in Chinese with English abstract).