| 摘要: |
| 镉（Cd）是对动植物有严重危害的一种重金属，但关于它如何进入细胞以及它对植物发育影响的研究很少。通过观察Cd暴露下的3种植物——凤仙花、牵牛花、紫茉莉的生长状况，用台盼蓝染根细胞核和通过叶表皮造模技术观察气孔变化，初步研究了Cd进入细胞的可能途径，提出了Cd进入植物体内的细胞模型，并观察了Cd对气孔发育的影响。结果表明：Cd环境暴露下，用台盼蓝染色凤仙花的根可使其根毛细胞核染色，而对照不被染色。根据三种植物在Cd暴露条件下的生长状况和植株死亡时的表现，提出了Cd进入细胞的模型：Cd首先与细胞膜上的蛋白质结合，使细胞膜上形成可以允许Cd2+或其他离子进出细胞的孔，Cd通过扩散进入细胞；与膜蛋白结合的Cd为可逆结合，依据Cd浓度形成平衡。Cd影响气孔的开闭和发育。当Cd浓度变化时，气孔闭合率也发生变化。在叶子的发育中，如果有Cd的存在，气孔的发育偏离原有的进程，牵牛花叶子的副卫细胞消失，同时气孔数量减少。对Cd敏感的凤仙花的气孔密度严重减少，紫茉莉和牵牛花气孔则少量减少。同时叶表皮细胞壁的弯曲形状也发生较大变化，表皮细胞也明显变小。 |
| 关键词: Cd 质膜 气孔 副卫细胞 凤仙花 牵牛花 紫茉莉 |
| DOI：10.7515/JEE192012 |
| CSTR：32259.14.JEE192012 |
| 分类号: |
| 基金项目:陕西省自然科学基金项目（2016JM3021）；陕西学前师范学院大学生创新创业训练计划项目（105050172） |
| 英文基金项目:Natural Science Foundation of Shaanxi Province (2016JM3021); Innovation and Entrepreneurship Training Program for College Students of Shaanxi Xueqian Normal University (105050172) |
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| Mechanism of plant cell absorb cadmium and its influence on stoma development |
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ZHENG Hongchun, LIU Jiao, WANG Han, WANG Miao
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Life Science & Food Engineering College, Shaanxi Xueqian Normal University, Xian 710100
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| Abstract: |
| Background, aim, and scope Cadmium (Cd) is a heavy metal that causes serious damage to plants and animals, but little research has been done on how it gets into cells and how it affects plant development. In this paper, how Cd got into plant cells and how the stoma developed when Cd existed were studied. Materials and methods By investigating the growing states of Impatiens balsamina L., Pharbitis nil (L.) Choisy and Mirabilis jalapa L. in cadmium pollution environment, using Typan Blue stain root cells, and making model of leave epidermis, the possible way of cadmium got into cells was studied, and a model for cadmium got into plant cells was put forward. At the same time, the influence of cadmium on stoma development was investigated. Results When I. balsamina L. grown in culture solution containing cadmium, the root cells nuclear could be stained by Typan Blue, if not, the root cells nuclear couldn’t be stained. The number of stomas was reduced and more stomas closed than the plants grown in culture solution without cadmium. P. nil (L.) Choisy had subsidiary cells in normal development, but the subsidiary cells did not appear if there was Cd. The number of stomas decreased when there were Cd, while the stomas number of I. balsamina L. decreased most. At same time the epidermis cell wall had a difference. Discussion The existing results suggested that Cd absorption was not related with ATPase and it had little relationship with the Cd flow of high cadmium on the root surface. Cd could influence the development of secondary structures. All of the results did not contradict the results of our experiment. Conclusions Cd destroyed cell membrane, allowing Cd2+ to entry cells freely, thus the plant development and the function were inhibited. Recommendations and perspectives Based on the grow state of three species and the morphology of the plant dead, the model of cadmium entered into plant cells was put forward, that was: the cadmium first combined with protein on membrane, then formed a pore near the protein and finally diffused into plant cell. Cd2+ combined with protein could also dissociate. Cadmium affected stomatal opening and closing, when there were Cd, the more stomas closed. In the development of leaf, if there were Cd, the stomas developed through a different way. |
| Key words: cadmium membrane stoma subsidiary cell Impatiens balsamina L., Pharbitis nil (L.) Choisy Mirabilis jalapa L. |
