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Potassium antimonite was used to localize Ca2+ in the apical bud cells of spruce from July 1999 to May 2000. During the period of active growth (July 14), Calcium precipitates, an indication of Ca2+ localization, were mainly distributed in vacuoles, intercellular spaces and cell walls. Few Ca2+ deposits localized in the cytosol and nucleus, showing a low level of the cytosolic and nuclear Ca2+ concentration in the warm summer. In August, some Ca2+ deposits appeared in the cytosol and nuclei, indicating that Ca2+ influx occurred in the cytosol and nucleus as the day length became shorter. From September to November, high levels of the cytosolic and nuclear Ca2+ remained. During the mid-winter (December and January), the distribution of Ca2+ deposits and the ultrastructures in the cells were altered dramatically. Plasmolysis occurred in many cells due to the protoplasmic dehydration. In addition plasmalemma invagination and nuclear chromatin aggregation also occurred. A large number of Ca2+ deposits appeared in the space between the plasmalemma and the cell wall. And also some Ca2+ deposits were distributed in the plastids. However, few Ca2+ deposits were observed in the cytosol and nuclei. By spring of the next year (May), when plants were de-acclimated and resumed active growth, Ca2+ subcellular localization essentially restored to that observed in July of the last year, i.e., the cells contained low cytosolic and nuclear Ca2+ concentrations; Ca2+ deposits were mainly distributed in the vacuoles, cell walls and intercellular spaces. The relationships between the seasonal changes of intracellular Ca2+ concentration and the development of dormancy/cold acclimation, as well as plasmolysis associated with dormancy and cold hardiness were discussed.
Potassium antimonite was used to localize Ca2 + in the apical bud cells of spruce from July 1999 to May 2000. During the period of active growth (July 14), Calcium precipitates, an indication of Ca2 + localization, were mainly distributed in vacuoles, intercellular spaces and cell walls. Few Ca2 + deposits localized in the cytosol and nucleus, showing a low level of the cytosolic and nuclear Ca2 + concentration in the warm summer. In August, some Ca2 + deposits appeared in the cytosol and nuclei, indicating that Ca2 + influx occurred in the cytosol From September to November, high levels of cytosolic and nuclear Ca2 + remained. During the mid-winter (December and January), the distribution of Ca2 + deposits and the ultrastructures in the cells were altered dramatically. Plasmolysis occurred in many cells due to the protoplasmic dehydration. In addition plasmalemma invagination and nuclear chromatin aggregation included.. A large number of C And also some Ca2 + deposits were observed in the cytosol and nuclei. By spring of the next year (May), when plants were de-acclimated and resumed active growth, Ca2 + subcellular localization essentially restored to that observed in July of the last year, ie, the cells contained low cytosolic and nuclear Ca2 + concentrations; Ca2 + deposits were mainly distributed in the vacuoles, cell walls and intercellular spaces . The relationships between the seasonal changes of intracellular Ca2 + concentration and the development of dormancy / cold acclimation, as well as plasmolysis associated with dormancy and cold hardiness were discussed.