渗透胁迫下玉米幼叶细胞Ca^(2+)分布及超微结构变化

The changes of Ca^(2+) localization in cells and cytological electromicroscopic structure of Zea mays L. leaflets under osmotic stress

采用改进的焦锑酸钙沉淀细胞化学方法,探讨了渗透胁迫条件下玉米幼叶胞内Ca2+的分布及细胞超微结构的变化,旨在进一步探讨Ca2+与渗透胁迫诱导胞内信息转导过程的关系。结果表明:干旱胁迫初期,胞质Ca2+浓度升高,液泡失水,叶绿体、细胞核Ca2+浓度升高,起到了调节胞内Ca2+浓度的作用;随着胁迫时间的延长,细胞超微结构遭到破坏,同时,叶绿体及细胞核中Ca2+浓度呈继续上升趋势,二者超微结构受到破坏的程度愈发严重,直至解体。说明:Ca2+介导了渗透胁迫诱导的细胞生理过程,Ca2+对细胞核骨架的可塑性发挥着重要作用。

In order to study the relationship between cytosolic Ca^2＋ and physiological process triggered by osmotic stress, the changes of Ca^2＋ localization in cells and cytological electromicroscopic strcture of mays leaflets under PEG6000 stress were investigated with calcium antimorate precipitate-electron microscopic-cyrochemical metrods. It was shown that at the beginning of the stress, the free [Ca^2＋ ] in cytoplasm was increased. With the water lost in vacuoles, the level of Ca^2＋ both chloroplast and nucleus were increased considerably, and as the pool of calcium, both of two organelles played an important role in regulating the concentration of Ca^2＋ in cytoplasm. With the longer of osmotic stress, the ultrastructure of cells were damaged, the Ca^2＋ both chloroplast and nucleus were increased more, the ultrastrcture of the two organelles were damaged seriously,and then depolymerized. This indicated that Ca^2＋ intervened in the physiological process induced by osmotic stress, and it played an important role in regulating nucleus frame change.