【摘要】 为探讨香樟在低温胁迫下叶肉细胞超微结构的变化,揭示香樟于低温胁迫下细胞水平上的响应机制,以2年生香樟幼树为试材,于5℃、0℃、-10℃条件下处理24 h,用透射电子显微镜观察叶肉细胞超微结构的变化。结果表明:5℃处理时,叶绿体排列整齐,有轻微肿胀现象,只有少量叶绿体中含淀粉粒、嗜锇体,线粒体双层膜及嵴结构完整;0℃处理时叶绿体膨胀加剧,嗜锇体增多,线粒体数目增多且聚集在一起,细胞核结构完整;-10℃处理时,细胞出现了质壁分离现象,叶绿体崩溃解体,线粒体数量减少,细胞核失去正常结构。叶绿体、线粒体、细胞核和液泡内晶体的稳定性可作为香樟耐寒性鉴定的重要参考指标。更多还原

【Abstract】 To investigate the changes in the mesophyll cell ultrastructure of C. camphora,which was introduced from southern to northern China,and to determine a cytological basis for the response mechanism to low-temperature stress,2-year-old C. camphora was used as the test material and was treated with 5 ℃,0 ℃ and-10 ℃ for 24 hours. Then the ultrastructural changes in mesophyll cells were observed by transmission electron microscope. At 5 ℃,permutations of chloroplast were neat with a slight oncotic phenomenon;just a few chloroplasts contained starch grains and osmiophilic granules; the structures of mitochondrial double membranes and cristae were complete. At 0 ℃,the chloroplast swelling increased; osmiophilic granules in chloroplasts increased; the number of mitochondria increased and gathered together and the structures of nuclei were complete. At 10 ℃,cells appeared the phenomenon of plasmolysis;chloroplasts collapsed and disintegrated; the number of mitochondria reduced and nuclei lost normal structures. The stabilization of chloroplasts,mitochondria,nuclei and the crystal in multivesicular bodies can be used as important reference indexes for identification of cold resistance of C. camphora.更多还原