环境因素对菹草根和叶细胞质膜Ca^(2+)-ATPase活性的影响

Impact of environmental factors on Ca^(2+)-ATPase activity of Potamogeton crispus root and leaf plasma membrane

通过改变溶液温度、pH值、ATP浓度、钙浓度和培养液的钙浓度等条件,研究了菹草根和叶细胞质膜Ca2+-ATPase的活性的变化.结果表明,根细胞质膜Ca2+-ATPase的活性在pH 6.0时最高,其最适反应温度为40℃;叶细胞质膜Ca2+-ATPase在一个较宽的pH范围内具有高活性,最适反应温度为45℃;溶液中ATP浓度分别为3mmol/L和4mmol/L时菹草根和叶细胞质膜Ca2+-ATPase活性最大;无论是菹草根还是叶细胞质膜Ca2+-ATPase活性,在溶液钙浓度为10-4mol/L时都最高.在营养液中添加不同CaCl2浓度培养菹草,其根和叶细胞质膜Ca2+-ATPase活性表现出差异,根细胞质膜Ca2+-ATPase活性比叶细胞质膜Ca2+-ATPase活性高,且随营养液中钙浓度的增加,这种差异加大;当营养液中钙浓度在10mg/L(2.5×10-4 mol/L)以下时,Ca2+-ATPase活性逐渐上升,营养液中钙浓度由10mg/L增加到15mg/L,Ca2+-ATPase活性陡然下降,这与溶液钙浓度对Ca2+-ATPase活性的影响相呼应.

Ca2＋-ATPase activity of P.crispus root and leaf plasma membrane was studied by changing the solution conditions including temperature,pH value,ATP concentration,and calcium concentration.The results indicated that the activity of root plasma membrane Ca2＋-ATPase reached the maximum at pH 6.0 and 40 ℃,while the leaf enzyme highly activated at a broad range of pH at an optimum reaction temperature of 45℃.Plasma membrane Ca2＋-ATPase activity in the root reached the maximum at 3 mmol/L ATP and in the leaf at 4 mmol/L ATP in the solution.P.crispus root and leaf plasma membrane Ca2＋-ATPase activity increased up to the presence of 10-4 mol/L calcium in the solution.The alteration of CaCl2 concentration in culture solution for P.crispus cultivation resulted in different Ca2＋-ATPase activity in both root and leaf plasma membrane.The root plasma membrane Ca2＋-ATPase activity was higher than in the leaf,and the difference was more remarkable with increments of calcium in the culture solution.At lower concentration of calcium than 10 mg/L（2.5×10-4 mol /L） in the culture solution,the Ca2＋-ATPase activity was raised gradually.Between 10 mg/L to 15 mg/L,Ca2＋-ATPase activity dropped sharply,which is in agreement with the impact of calcium concentration on Ca2＋-ATPase activity.