【摘要】 用蔗糖密度梯度离心法分离了水培不结球白菜品种上海青叶柄与叶片液泡膜,并测定了与硝酸盐运输相关的质子泵的水解活性。结果表明,液泡膜纯度达到35%~40%;在离体条件下,叶片和叶柄中H+-ATPase和H+-PPase的最佳pH值均为8.0左右;叶柄细胞液泡膜H+-ATPase和H+-PPase的水解活性显著高于叶片,且叶柄液泡膜上H+-ATPase和H+-PPase有较高的Vm ax值。试验表明,硝酸盐在叶柄与叶片中的积累差异与其液泡膜上的质子泵活性大小密切相关。更多还原

【Abstract】 The hydrolytic activity of tonoplast H⁺-pumping,that is related to the active nitrate transport,was studied by using the tonoplast isolated from leaf and petiole of hydropnics non-heading Chinese cabbage（Brassica chinensis L.’Shanghaiqing’）with sucrose gradient.The results showed that the purity of tonoplast was 35%-40%,and in vitro,the pH optimum for H⁺-ATPase and H⁺-PPase was pH 8.0.Both hydrolytic activity and V_max of H⁺-ATPase and H⁺-PPase from petioles were higher than those from leaves.This study indicated that the difference of nitrate accumlation between petiole and leaf might be related to the tonoplast H⁺-pumping activity.更多还原