Impairment of Tonoplast H-ATPase as an Initial Physiological Response of Cells to Chilling in Mung Bean (Vigna radiata [L.] Wilczek).
Impairment of Tonoplast H-ATPase as an Initial Physiological Response of Cells to Chilling in Mung Bean (Vigna radiata [L.] Wilczek).
复制标题
绿豆 (Vigna radiata [L.] Wilczek) 中液泡膜 H-ATP 酶的损伤是细胞对寒冷的初始生理反应。
作者：
Shizuo Yoshida;Chie Matsuura;Shuichi Etani
低温敏感绿豆（Vigna radiata [L.] Wilczek）下胚轴的冷害进行了研究。当组织没有受到永久性损伤时，通过电解质渗漏和再生能力评估，在低温24小时内，液泡膜H（+）-ATPase活性和体内呼吸的可逆性降低变得明显。这些变化被认为是细胞对寒冷的最早反应。在低温处理的早期，在高尔基体膜上观察到蔗糖密度梯度的密度变化，这表明高尔基体功能和/或通过高尔基体的膜生物合成可能在低温下发生了改变。低温超过2天后，细胞膜，包括质膜、内质网和线粒体，通常产生不可逆的变化。从预冷24小时的组织中分离的线粒体的呼吸功能保持完整，但在预冷3天后受损。由于液泡膜H（+）-ATP酶在离子和代谢物的主动运输中起重要作用，液泡膜H（+）-ATP酶活性的早期下降可能引起细胞质环境的改变，从而引发细胞中的一系列退化反应。
Biochemical alterations of cellular membranes in chilling-sensitive mung bean (Vigna radiata [L.] Wilczek) hypocotyls were investigated with reference to chilling injury. Reversible decreases in activities of tonoplast H(+)-ATPase and in vivo respiration became manifest within 24 hours of chilling when tissues suffered no permanent injury as assessed by electrolyte leakage and regrowth capacity. These changes were found to be the earliest cellular responses to chilling. A density-shift on a sucrose density gradient was observed in Golgi membranes early in the chilling treatment, suggesting that Golgi function and/or membrane biogenesis via the Golgi may have been altered upon chilling. After chilling more than 2 days, irreversible changes were generally produced in cellular membranes including the plasma membrane, endoplasmic reticulum, and mitochondria. Respiratory functions remained intact in mitochondria isolated from tissues prechilled for 24 hours, but were impaired after prechilling for 3 days. Given the important role of the tonoplast H(+)-ATPase in the active transport of ions and metabolites, the early decline in the tonoplast H(+)-ATPase activity may give rise to an alteration of the cytoplasmic environment and, consequently, trigger a series of degenerative reactions in the cells.