细胞膜质子泵在水稻耐铵机制中的作用机理探讨

Investigation on the Mechanism of Adaption of Plasma Membrane H^+-ATPase to Ammonium Nutrition in Rice

水稻是一种典型的耐铵植物。由于铵态氮营养条件会导致根系分泌大量的氢离子,对植物生长产生胁迫。因此,耐铵植物应具备耐酸的能力。细胞膜质子泵具有主动排出质子,调节细胞内外pH的功能。结合目前的研究结果,探讨了水稻根系细胞膜质子泵在铵态氮与低pH两个因素交叉作用下活性的变化及其调节机制,以阐明水稻耐铵的一个必要机制。上述结果对于丰富植物耐铵机制的研究具有重要的理论与实践意义。

The preference of paddy rice for NH4＋ rather than NO3-is associated with its tolerance to low pH since a rhizosphere acidification occurs during NH4＋ absorption.However,the adaptation of rice root to low pH has not been fully elucidated.The plasma membrane H＋-ATPase is a universal electronic H＋ pump,which uses ATP as energy source to pump H＋ across plasma membranes into the apoplast.The key function of this enzyme is to keep pH homeostasis of plant cells and generate a H＋ electrochemical gradient,thereby providing the driving force for the active influx and efflux of ions and metabolites across the plasma membrane.The acclimation of plasma membrane H＋-ATPase of rice root to low pH may be partly responsible for the preference of rice plants to NH4＋ nutrition.