NaCl盐胁迫对两种刺槐叶肉细胞超微结构的影响

以四倍体刺槐为主要研究材料、二倍体刺槐为对照材料,观察二者在NaCl胁迫下叶肉细胞的超微结构变化特点。结果表明:1)在盐胁迫处理前,二者的叶绿体均表现为结构完整。处理10d时,二倍体刺槐的叶绿体出现变形、膜模糊、基粒片层松散;处理20d时,叶绿体进一步肿胀、变形,膜系统全部解体。对四倍体刺槐进行同时期的观察发现:处理10和20d时,其叶绿体形态与二倍体刺槐的相比差异不大。2)盐胁迫处理前,二者叶片的线粒体形态饱满,结构完整。处理10d,二倍体刺槐的线粒体膜模糊,失去完整性,内部出现部分空洞,嵴结构模糊;盐胁迫20d时,二倍体刺槐的线粒体膜结构几乎全部失去完整性,与周围介质相融,无结构清晰的嵴,线粒体内部绝大部分出现空洞。而四倍体刺槐叶肉的线粒体在盐胁迫过程中与处理前相比变化不大。3)处理前,二者的叶肉细胞均表现为排列疏松,结构完整,叶绿体分布于细胞边缘。处理10d时,二倍体刺槐的部分叶绿体位于细胞中央;盐胁迫20d时,绝大部分叶绿体进入细胞内部,游离细胞壁,呈随机分布,且细胞膜部分破损,变得模糊。而四倍体刺槐叶肉细胞的超微结构在盐胁迫过程中变化不大。以上结果可以看出,四倍体刺槐具有与耐盐性相适应的解剖结构特点。

Ultrastructure of mesophyll cells in two Robinia pseudoacacia hybrids under NaCl stress

The ultrastructural changes of mesophyll cells in two Robinia pseudoacacia hybrids, i.e. tetraploid R. pseudoacacia and diploid R. pseudoacacia, were observed under NaCl stress. The results showed that: 1) before salt stress, the chloroplasts of two R. pseudoacacia were morphologically integrated. After 10 days of stress, the chloroplast of diploid R. pseudoacacia began deformed, with ambiguity in membrane and disorganization in grana lamell. After 20 days, the chloroplast showed further swelling and disarrangement, with a clear degradation of membrane. For tetraploid R. pseudoacacia, the structure of chloroplast changed little after 10 and 20 days of stress; 2) Before salt stress, the mitochondria of two R. pseudoacacia were morphologically integrated. After 10 days of stress, the cavitas and ambiguous crista were observed in the mitochondria of diploid R.pseudoacacia, which appeared ambiguity in membrane and lost integrity. After 20 days, most of mitochondria lost complete membrane and showed compatible with cytoplasm; no clear cristae but many cavitas were observed. The mitochondria of tetraploid R. pseudoacacia changed little with salt stress; 3) Before salt stress, the mesophyll cell of two R. pseudoacacia showed loose arrangement and complete structure. The chloroplast distributed at the margin of the cell wall. After 10 days, parts of chloroplast in diploid R. pseudoacacia moved to the middle of cell. After 20 days, most of chloroplast located in the middle of cell and showed random distribution; cell membrane degraded partly and became ambiguity. The shape of mesophyll cell of tetraploid R. pseudoacacia changed little under salt stress. The above results indicate that tetraploid R. pseudoacacia has anatomic adaptation to the salt stress.