Stained with Fluo-3/AM and investigated under the laser scanning confocal microscope (LSCM), the spatial-temporal changes of ［Ca2+］cyt(the free Ca2+ concentration in the cytoplasm) in the protoplasts of mesophyll cells of wheat (Triticum aestivum L.) cultivars with different cold-hardiness under resting and temperature decreasing conditions were compared. The results showed that under the resting condition, the fluorescence intensities in the protoplasts of both cold-sensitive and cold-resistant wheat manifested no significant changes, implying that ［Ca2+］cyt could keep at a stable level under the resting condition although different wheat cultivars were different. However, different dynamics appeared with temperature decreasing from 15℃ to 2℃. In particular, for the cold-resistant wheat, ［Ca2+］cyt level at first increased, followed by drop to the resting level at 2℃, and then increased further when the temperature was below 2℃. On the contrary, the ［Ca2+］cyt level of the cold-sensitive spring wheat increased continuously to the maximal level within the whole range of temperature changes. Based on the above observations, it could be reasonably inferred that different dynamics of ［Ca2+］cyt determines decisively different cold acclimation abilities of plants. Furthermore, the results provide a new supporting evidence for the hypothesis that Ca2+ plays a key role as a primary physiological transducer upon chilling”.
低温处理对冬、春小麦细胞Ca2+ 时空变化的影响
刘炜1,3 孙德兰1* 王红1 简令成1 尚忠林2 王学臣2 赵可夫3
（1 中国科学院植物研究所，北京100093；2. 中国农业大学生物学院，农业部植物生理生化重点开放实验室，北京100094；3.山东师范大学逆境植物研究所，济南250014）
摘要：用Fluo-3/AM染色,通过激光扫描共聚焦显微镜(LSCM)方法,对静息态及连续降温条件下不同抗寒性小麦(Triticum aestivum L.)叶肉细胞原生质体[Ca2+]cyt (the free Ca2+ concentration in the cytoplasm)的时空变化进行了比较.结果表明,静息态下小麦原生质体整体荧光强度基本不变,暗示[Ca2+]cyt能维持在一稳定水平;同时,不同品种小麦间也显示了[Ca2+]cyt水平荧光强度的不同.温度由15 ℃连续降至约2 ℃时,抗寒冬小麦[Ca2+]cyt出现升高后的回复,2 ℃之后逐渐升高;冷敏感春小麦则无此回复过程,而是一直升高到最大值.推测这一不同的动态变化最终决定了植物在低温下产生冷适应的不同能力.这进一步为"Ca2+是低温下生理信号的传导者"这一假说提供了新的证据.
关键词： Flou-3/AM；小麦原生质体；静息态；［Ca2+]cyt时空变化
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