摘要： 探讨低温胁迫下甘蓝叶片细胞超微结构特征、细胞内Ca2+分布变化及品种间差异,为越冬甘蓝的耐寒性机理研究及耐寒品种选育提供理论依据。采用低温培养箱模拟逆境条件处理甘蓝幼苗,研究其对甘蓝叶片细胞超微结构及细胞内Ca2+分布的影响并比较了品种间差异。5℃低温处理时,甘蓝叶片大多数细胞器基本无损,排列有序,表明耐冷材料和冷敏材料均能适应5℃低温环境。在-3℃低温胁迫下,耐冷材料叶片超微结构破坏较小,而冷敏材料叶绿体结构破坏严重,基粒片层断裂、降解;线粒体多数扭曲变形,已无明显内脊。对照生长条件下(25/18℃),甘蓝幼苗叶肉细胞内Ca2+主要出现在液泡和细胞间隙中,细胞壁、细胞核中也有少量钙沉淀存在。在-3℃低温处理24 h后,耐冷材料细胞质和细胞核中的Ca2+浓度明显增加,冷敏材料细胞质中Ca2+也有增加,但较耐冷材料少。在低温处理24～72 h的过程中,耐冷材料细胞内增加的Ca2+浓度迅速降低,并恢复至处理前状态;而此阶段内冷敏材料因其细胞结构遭到严重破坏,细胞质中的Ca2+浓度升高到最大值后,无法恢复至稳定状态。低温胁迫下甘蓝叶片的超微结构特征及细胞内Ca2+行为特征表现显著差异,表明甘蓝叶片的超微结构特征及Ca2+分布变化与其抗寒性存在一定关系。

关键词: 低温, 甘蓝, 超微结构, Ca2+分布

Abstract: The objective of the study is to investigate the effects of low temperature stress on the leaf ultrastructure and Ca²⁺distribution of various cabbage varieties，and to find the different response mechanisms between them． The seedlings were treated separately under adverse temperature conditions in growth chambers，and the effects on cell ultrastructure and Ca²⁺distribution of cabbage leaves under low temperature stress were studied，and various cabbage varieties was compared． Under 5℃ cold stress，most leaf cell organelles of cabbage were not injured and orderly arranged． This sugGested that both cabbage varieties adapted to 5℃ cold stress． Under-3℃ cold stress， the ultrastructure of leaf cell in cold-resistant lines had little destructiveness，whereas， the grana lamella of leaf cell in cold-sensitive lines were disorganized and mitochondrion's cristae could not be found． Under optimum temperature (25 /18℃) conditions，calcium antimonite deposits，which indicates calcium distribution，were mainly localized in vacuoles and intercellular space， and few was found in cell wall or nucleus． At controlled temperature of-3℃ for 24 h， an elevation of Ca²⁺level in the cytosol and nucleus was observed in two varieties，wheas the cold-sensitive lines had few than cold-resistant lines． By chilling up to 48 and 72 h， the intracellular Ca²⁺concentration had been restored to a similar low level as the status as treatment before． On the contrary， the Ca²⁺concentration of the cold-sensitive variety increased continuously to the maximal level within the whole range of temperature changes． This study indicated that there were distinctive differences between the cabbage species in cell ultrastructure and Ca²⁺distribution， It could be seen that cabbage cold-hardiness was related to the changes in cell ultrastructure and Ca²⁺distribution．

Key words: Cold temperature, Cabbage, Cell ultrastructure, Ca²⁺distribution

中图分类号: 

• S635． 01