Cd~(2+)对BY-2细胞的毒性机制及水杨酸的缓解作用

镉对生态环境的危害表现出对植物这种定生生物的毒害性。以绿色荧光蛋白(GFP)膜泡标记的烟草BY-2细胞为实验材料,分别在荧光显微镜和激光共聚焦显微镜下观察了Cd2+对植物细胞的毒害作用和机制,并研究了水杨酸(SA)处理对Cd2+植物细胞毒害的缓解作用。研究发现激光共聚焦显微镜可以观察到Cd2+处理3 h后细胞荧光亮度减弱,6 h时细胞皱缩和液泡缩小,9 h细胞大多死亡。在Cd2+胁迫同时加入SA,可显著提高细胞成活时间,荧光亮度增强、液泡化程度加大,同时能够观察到荧光标记的细胞膜包裹Cd2+的高荧光颗粒。SA处理的细胞还通过高度液泡化来缓解重金属Cd2+的毒性。结果表明具有生物活性的SA诱导细胞的液泡化,并通过膜成分对重金属的包裹和结合进一步降低了重金属对植物细胞的毒害。因此水杨酸缓解重金属对植物细胞的毒性,是通过诱导细胞的液泡化和膜对重金属离子的包裹束缚而实现的。

Cadmium Toxicology to Cultured BY-2 Cells and the Relief Effects of Salicylic Acid to the Cadmium Toxicity

The toxicity to immobilized plants is one of the most harmful effects of heavy mental cadmium to the ecological environment. In this paper the toxicity and mechanism of Cd²⁺ to plants cells were analyzed by fluorescence microscope and confocal laser scanning microscope observation in GFP membrane labeled BY-2 cell. The relief effects of salicylic acid (SA) treatment to the Cd²⁺ toxicity were also investigated. The results showed that the GFP fluorescence of the labeled cells was getting dimming after 3 h Cd²⁺ treatment. The cells and vacuoles were apparently shrunk after 6 h. All the cells were dead after 9 h treatment. When SA was also added during the Cd²⁺ treatment, the survival time of the treated cells were prolonged significantly. The SA and Cd²⁺ treated cells also showed stronger fluorescence and better vacuolization compared to the Cd²⁺ treatment. High fluorescence particles attached to the cell membrane were observed, indicating that there were wrapped Cd²⁺ microcapsules formed in SA treatment cells. The results suggest that the SA treatment can relieve the toxicity of heavy metals both by high vacuolization in the cells and by membrane components retention of the heavy metals ion. The conclusion is that the microcapsule retention and vacuolization of the cells induced by SA is the mechanism of the SA toxicity relief.