Extracellular freezing in leaves of freezing-sensitive species
Extracellular freezing in leaves of freezing-sensitive species
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DOI：
10.1007/s00425-001-0683-3
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发表时间：
2002-03-01
期刊：
影响因子：
4.3
通讯作者：
Pearce, RS
中科院分区：
文献类型：
--
作者：
Ashworth, EN;Pearce, RS
利用低温扫描电镜技术研究了5种不抗冻的植物的叶片受冻情况，烟草（Nicotiana tabacum L.）。番茄（Lycopersicon esculentum L.），黄瓜（Cucumis sativus L.），和玉米（Zea mays L.）。在四种双子叶植物的叶子里。冰是细胞外的，并且所有组织的细胞都塌陷。相反。在玉米叶片中，冰在叶肉的细胞外，并且这些细胞被破坏。但表皮细胞和束鞘细胞显然保持了原来的形状和体积。它的结论是，冷冻敏感的双子叶植物物种测试的叶片被杀死细胞外冷冻诱导的细胞脱水，而不是由细胞内冷冻。玉米叶片的冻害是由冷冻诱导的细胞脱水和表皮及叶鞘细胞内结冰共同作用的结果。
Low-temperature scanning-electron microscopy was used to study the freezing of leaves of five species that have no resistance to freezing: bean (Phaseolus vulgaris L.), tobacco (Nicotiana tabacum L.). tomato (Lycopersicon esculentum L.), cucumber (Cucumis sativus L.), and corn (Zea mays L.). In the leaves of the four dicotyledonous species. ice was extracellular and the cells of all tissues were collapsed. In contrast. in maize leaves ice was extracellular in the mesophyll, and these cells were collapsed. but the epidermal and bundle-sheath cells apparently retained their original shapes and volume. It is concluded that the leaves of the freezing-sensitive dicotyledonous species tested were killed by cellular dehydration induced by extracellular freezing, and not by intracellular freezing. Freezing injury in maize leaves apparently resulted from a combination of freezing-induced cellular dehydration of some cells and intracellular ice formation in epidermal and bundle-sheath cells.