灰岩皱叶报春和滇北球花报春在热锻炼和热胁迫下叶肉细胞超微结构的差异

Difference in Ultrastructure of Mesophyll Cell Between Two Primula Species with Different Thermotolerance Under Heat Acclimation and Heat Stress

为研究报春花属Primula植物对高温的响应机制,从超微结构的角度探讨热锻炼提高耐热性及不同品种耐热性差别的原因,利用透射电镜的方法,对耐热种灰岩皱叶报春P.forrestii和不耐热种滇北球花报春P.denticulate ssp.sinodenticulata进行了热锻炼(38℃,12h)和热胁迫(42℃)条件下细胞超微结构的观察.结果表明,热锻炼提高了核膜的热稳定性,延缓热胁迫对叶肉细胞超微结构的破坏,从而可提高细胞的耐热性.耐热种和不耐热种在热锻炼与热胁迫过程中的超微结构变化过程基本相同,只是被破坏的时间有差异;叶肉细胞中叶绿体比线粒体对高温敏感,在热胁迫过程中,存在线粒体数量增多的现象,推测是报春属植物对逆境的积极响应对策.

To study the response mechanism of Primula to high temperature and find the reasons for the enhancement of heat resistance after heat acclimation and the difference in heat resistance between different species from the perspective of the ultrastructure, the ultrastructure of mesophyll cell in heat-resistant species （Primulaforrestii）and non-heat-resistant species （P. denticulate ssp. sinodenticulata） were investigated under the heat acclimation （38℃ ,12 h） and heat stress （42℃ ） using the method of transmission electron microscopy. The results showed that heat acclimation improved thermotolerance of cell and thermal stability of nuclear membrane, and delayed the ultrastructural destruction in heat stress. The ultrastructural changes between heat-resistant species and non-heat-resistant species under the heat acclimation and heat stress was basically same, but the difference lay in the time of destruction ; mesophyll chloroplast was sensitive to heat than the mitochondria in the process of heat stress, the phenomenon of the number increase of mitochondria, suggesting that the genus Primula had a positive response to stress environment.