A comparative study was carried out on the EM_cytochemical localization of calcium and Ca 2+ _ATPase activity in the suspension_cultured cells between the chilling_sensitive maize ( Zea mays L. cv. Black Mexica...A comparative study was carried out on the EM_cytochemical localization of calcium and Ca 2+ _ATPase activity in the suspension_cultured cells between the chilling_sensitive maize ( Zea mays L. cv. Black Mexican Sweet) and chilling_insensitive Trititrigia ( Triticum sect. Trititrigia mackey) at 4 ℃ chilling. When maize and Tyititrigia cells were cultured at 26 ℃, electron microscopic observations revealed that the electron_dense calcium antimonate deposits, an indication of the calcium localization, were localized mainly in the vacuoles, and few was found in the cytosol and nuclei. The electron_dense cerium phosphate deposits, an indication of Ca 2+ _ATPase activity, were abundantly distributed on the plasma membrane (PM). When the cells from both species were cultured at 4 ℃ for 1 and 3 h, an elevation of Ca 2+ level in the cytosol and nuclei was observed, whereas the cerium phosphate deposits on the PM showed no quantitative difference from those of the 26 ℃_cultured cells, indicating that the enzymatic activities were not altered during these chilling periods. However, there was a distinct difference in the dynamics of the Ca 2+ distribution and the PM Ca 2+ _ATPase activity between maize and Trititrigia when chilled at 4 ℃ for 12, 24 and 72 h. In maize cells, a large number of Ca 2+ deposits still existed in the cytosol and nuclei, and the PM Ca 2+ _ATPase became less and less active, and even inactive at all. In Trititrigia cells, the increased cytosolic and nuclear Ca 2+ ions decreased after 12 h chilling. By chilling up to 24 and 72 h, the intracellular Ca 2+ concentration had been restored to a similar low level as those of the warm temperature_cultured cells, while the activity of the PM Ca 2+ _ATPase maintained high. The transient cytosolic and nuclear Ca 2+ increase and the activities of PM Ca 2+ _ATPase during chilling are discussed in relation to plant cold hardiness.展开更多
本研究根据植物细胞的特点,修改了在动物和人体细胞方面建立的酶标Con A的电镜细胞化学方法,成功地展现了冬小麦(Triticum aesti vum L.)幼叶细胞膜系统上糖蛋白的分布状况。揭示在适宜温度生长条件下,标志糖蛋白存在的辣根过氧化物酶...本研究根据植物细胞的特点,修改了在动物和人体细胞方面建立的酶标Con A的电镜细胞化学方法,成功地展现了冬小麦(Triticum aesti vum L.)幼叶细胞膜系统上糖蛋白的分布状况。揭示在适宜温度生长条件下,标志糖蛋白存在的辣根过氧化物酶活性的反应产物成颗粒状分散分布在质膜、内质网、核膜及液泡膜上。在经过秋末冬初低温锻炼后的麦苗细胞内,糖蛋白在内质网和核膜上的分布量明显地增加;同时,在几乎所有观察到的胞间连丝中都存在糖蛋白的分布;并在线粒体膜和质体膜上出现一些糖蛋白的位点。然而在整个观察中始终未能观察到高尔基体上有糖蛋白的存在。作者讨论了低温锻炼中糖蛋白输入胞间连丝在提高和稳定植物抗寒力上的作用,以及高等植物细胞内糖蛋白的合成地点和运输途径与动物细胞可能存在的差异。展开更多
文摘A comparative study was carried out on the EM_cytochemical localization of calcium and Ca 2+ _ATPase activity in the suspension_cultured cells between the chilling_sensitive maize ( Zea mays L. cv. Black Mexican Sweet) and chilling_insensitive Trititrigia ( Triticum sect. Trititrigia mackey) at 4 ℃ chilling. When maize and Tyititrigia cells were cultured at 26 ℃, electron microscopic observations revealed that the electron_dense calcium antimonate deposits, an indication of the calcium localization, were localized mainly in the vacuoles, and few was found in the cytosol and nuclei. The electron_dense cerium phosphate deposits, an indication of Ca 2+ _ATPase activity, were abundantly distributed on the plasma membrane (PM). When the cells from both species were cultured at 4 ℃ for 1 and 3 h, an elevation of Ca 2+ level in the cytosol and nuclei was observed, whereas the cerium phosphate deposits on the PM showed no quantitative difference from those of the 26 ℃_cultured cells, indicating that the enzymatic activities were not altered during these chilling periods. However, there was a distinct difference in the dynamics of the Ca 2+ distribution and the PM Ca 2+ _ATPase activity between maize and Trititrigia when chilled at 4 ℃ for 12, 24 and 72 h. In maize cells, a large number of Ca 2+ deposits still existed in the cytosol and nuclei, and the PM Ca 2+ _ATPase became less and less active, and even inactive at all. In Trititrigia cells, the increased cytosolic and nuclear Ca 2+ ions decreased after 12 h chilling. By chilling up to 24 and 72 h, the intracellular Ca 2+ concentration had been restored to a similar low level as those of the warm temperature_cultured cells, while the activity of the PM Ca 2+ _ATPase maintained high. The transient cytosolic and nuclear Ca 2+ increase and the activities of PM Ca 2+ _ATPase during chilling are discussed in relation to plant cold hardiness.
文摘本研究根据植物细胞的特点,修改了在动物和人体细胞方面建立的酶标Con A的电镜细胞化学方法,成功地展现了冬小麦(Triticum aesti vum L.)幼叶细胞膜系统上糖蛋白的分布状况。揭示在适宜温度生长条件下,标志糖蛋白存在的辣根过氧化物酶活性的反应产物成颗粒状分散分布在质膜、内质网、核膜及液泡膜上。在经过秋末冬初低温锻炼后的麦苗细胞内,糖蛋白在内质网和核膜上的分布量明显地增加;同时,在几乎所有观察到的胞间连丝中都存在糖蛋白的分布;并在线粒体膜和质体膜上出现一些糖蛋白的位点。然而在整个观察中始终未能观察到高尔基体上有糖蛋白的存在。作者讨论了低温锻炼中糖蛋白输入胞间连丝在提高和稳定植物抗寒力上的作用,以及高等植物细胞内糖蛋白的合成地点和运输途径与动物细胞可能存在的差异。
