盐胁迫对甜菊细胞内游离Ca2+浓度的影响

钙离子不仅是植物生长发育所需的一种大量元素,而且起了偶联细胞外刺激与胞内反应第二信使的作用,是多种受体激动后信息传递过程的中心环节。近年的研究表明:高温、干旱、触摸、低渗、低温、风、机械刺激、病原菌感染等多种环境胁迫均能引起胞质Ca~(2+)水平的改变。这种变化被认为是植物细胞感受环境胁迫的原初反应之一,它通过启动基因表达和胞内一系列生理生化过程调节细胞对环境改变的适应反应。胞质Ca~(2+)水平的改变有两种来源:胞外Ca~(2+)跨膜内流和胞内钙库如内质网中的Ca~(2+)释放。其中由肌醇磷

EFFECTS OF SALINITY STRESS ON CYTOSOLIC CALCIUMIN STEVIA REBA UDIANA BERTONI CELLS

Fluo-3/AM,a calcium indicator, was introduced by low temprature loading method into callus protoplasts of Stevia rebaudiana Bertoni. The microscope observation results showed that NaCl in different concentrations(30 - 200mmol/L) can elevate the intracellular calcium concentration in protoplasts. The elevation was related to the amount of salinity. The effect of salinity stress was inhibited by LiCl pretreatment but restored by inositol pretreatment. This suggested that salinity stress promoted the cytoplasmic calcium activity, perhaps by activating the phosphoinoditide system. As a result of salinity stress signals,elevated calcium activity may trigger corresponding metabolic changes, such as synthesis of enzyme via activating other members of calcium signal system, fit the cells for the change of the environment.