苗期低温胁迫对不同棉花品种叶肉细胞超微结构的影响

以早熟、中熟、晚熟三种不同熟性的6个棉花品种幼苗为试材,分析4℃低温胁迫处理对叶肉细胞超微结构的影响。结果表明：4℃低温处理3 d后,中熟品种N177和N181及晚熟品种K-1和N203的细胞器均受到严重破坏,表现为叶绿体受损严重,部分类囊体解体,线粒体膜模糊,失去完整性,细胞核膜基本消失,染色质凝聚,淀粉粒的数量和体积增大,嗜锇颗粒增多;而早熟品种中50和N52受损较轻,叶绿体变化不明显,线粒体结构完整,细胞壁完整。说明早熟品种中50和N52具有与抗冷性相适应的结构特点,其抗冷性较强。

Effect of Low Temperature Stress on Ultrastructure of Mesophyll Cells in Cotton Seedling Stage

The ultrastructural changes of mesophyll cell in six cotton varieties,including two early-maturing varieties＂Zhong 50 ＂and ＂N52 ＂,two medium-maturing varieties ＂N177 ＂ and ＂N181 ＂,and two late-maturing varieties＂N203＂and＂K-1＂,were observed under 4 ℃ low temperature stress for 3 days. The results showed that various organelles of six cotton varieties maintained morphological integrity before low temperature stress. After 3 days of 4℃ stress,the chloroplast of four varieties（N177,N181,N203 and K-1） began deformed and thylakoids were blurred. The ambiguous membrane was observed in the mitochondria and lost integrity. Much of karyotheca disappeared,chromatin condensed,osmiophilic particles increased,and the starch granule became much more and bigger. After 3 days of 4℃stress,the chloroplast and mitochondria of the early-maturing varieties（Zhong 50 and N52） were morphologically integrated. The above results indicated that Zhong50 and N52 have anatomic adaptation to the low temperature stress.