热胁迫下不结球白菜和甘蓝叶片组织结构的变化

利用显微及扫描电镜方法，研究不结球白菜及甘蓝的耐热品种和感热品种种在高温（３８－３９℃）胁迫下，叶片表皮和组织结构的差异。结果如下：耐热品种叶片下表皮比感热品种气孔频度高，气孔体积小且开张度小。耐热品种部分气孔呈关闭状态，而感热品种气孔基本上呈开放状态。显微结构观察到耐热品种叶肉组织细胞排列紧密，叶脉的维管束发达，特别是木质部的导管数量多且孔径大。而感热品种相比于耐热品种叶肉细胞排列疏松，维管束相

LEAF STRUCTURAL CHANGES OF BRASSICA CAMPESTRIS AND B.OLERACEA IN RESPONSE TO HEAT STRESS

The objective of this study was to investigate leaf tissue characteristics under heat stress in thermo-resistant cultivar and thermosensitive cultivar of Brassica campestris and B.oleracea with the methods of microscope,scanning electron microscope,the results obtained are summarized as follows:1.Leaf abaxial epidermis of thermo-resistant showed higher stomatal density, smallar stomatal openning area than thermo-sensitive cultivar under SEM, some stomata on abaxial epidermis of thermo-resistant cultivar were in close state, hut stomata of thermo-sensitive cultivar usually were in open state.2.The thermo-resistant cultivar had more xeromorphic features than the thermo-sensitive cultivars.Leaf anatomical structure showed that mesophyll cells of thermo-resistant cultivar arranged tightly and there were more and larger vessels in vascular bundle of lateral vein.The intercellular space in the mesophyll cells of sensitive cultivar and vascular systems were not fully developed and some spongy parenchyma cells showed severe plasmolysis.