外加Cd对两水稻品种细胞超微结构的影响研究

为了研究Cd在不同水稻品种(Oryza sativa L.)细胞中的分布位点及其耐Cd的具体表征状况,以子粒Cd积累水平不同的两水稻品种(品种A:中浙优1号,子粒高Cd含量品种;品种C:J196,子粒低Cd含量品种)为材料,进行盆栽实验,设不加Cd处理(CK)和加Cd处理(25mg·kg-1),采用透射电镜技术研究了外加Cd对两水稻品种细胞超微结构的影响.结果表明:Cd处理下两水稻品种的部分根细胞有Cd沉积现象,但不同品种的沉积部位表现不同,品种A主要在液泡边缘而品种C则在细胞壁和细胞间隙,表明不同水稻品种根系的耐Cd机制不同,品种A主要表现为液泡区室化,而品种C主要表现为细胞壁上有特定沉积.水稻叶肉细胞器中的叶绿体和线粒体是对Cd胁迫较为敏感的细胞器,外加Cd对茎叶细胞超微结构造成的伤害主要表现在使叶绿体上淀粉粒消失,叶绿体空泡化,部分线粒体出现肿胀或解体现象,品种C的受害程度高于品种A。

Effects of Cd Spiking on Cell Ultrastructure of Root and Leaf of Two Rice Cultivars

To examine the rice(Oryza sativa L.) genotypic difference in the alternation of cell ultrastructure and the toxicity position of cadmium(Cd)pollution on ultrastructure of different parts of cell, a pot experiment was conducted with two cultivars of hybrid rice, Zhongzheyou 1(high grain Cd accumulation) and J196(low grain Cd accumulation). Cd concentration of soil was 25mg·kg-1 spiked with reagent grade CdCl2·2.5H2O. Results showed that there was different Cd tolerance mechanism binding to cell wall or immobilization in vacuole between Zhongzheyou 1 and J196 through electronic microscopic observation. It appeared similar for both rice cultivars that chloroplasts and mitochondria were swelling up, and thylakoids vacuolized of ultrastructure of leaf causing by high concentration of Cd. But Cd aggravated the damage in the rice cultivar-J196, making mitochondrion mesenchyme dissolve and mitochondria be on the verge of disorganization. It was indicated that Cd tolerance on cell ultrastructure of Zhongzheyou 1 was higher than that on J196. It further demonstrated that mitochondria and chloroplast of rice mesophyll cells were the most sensitive organelles.