PLASMALEMMA ATPase OF HYPOCOTYL OF PEANUT SEEDLING AND ITS REACTION TO LOW TEMPERATUER STRESS

Plasma membrane were obtained from 7-day old peanut seedling hypocotyl by 6%～12% Dextran T70 density gradient centrifugation,with high quality and purity.Plasmalemma ATPase acts normally as hydrolyzing ATP without Mg²⁺ in reaction system, but the activity was lower than Mg²⁺-activated ATPase.Ca²⁺-ATPase wasn't inhibited by Na₃VO₄ and wasn't activitied by K⁺,whereas it is inhibited by Cl^-.The optimum pH of Ca²⁺-ATPase is different from that of Mg²⁺-activated ATPase.Plasma membrane Ca²⁺-ATPase activity increased notably under low temperature stress.It is suggest that the possible role of Ca²⁺-ATPase is adjusting Ca²⁺ concentration on cytoplasms.