不同浓度重铬酸钾溶液胁迫对洋葱根尖生理生化特性的影响

摘要

To provide references for exploring the physiological and biochemical mechanisms of chromium ions on plants, the effects of potassium dichromate (K2Cr2O7) with different treatment time on the mitosis and plant protection enzyme system of root tip cells of Allium cepa L. were studied. K2Cr2O7 solutions with different concentration were used separately to treat the root tip of A . cepa for 6, 12, 18, 24 h. The A . cepa root tip tissue were collected for tissue paraffin sections, hematoxylin and testing the activity of SOD, CAT, GST and the content of MDA. After the tip cell being prosessed by K2Cr2O7 solution with different concentration for different time, abnormal mitotic cell division and micronucleus were found in mitotic cells. No matter the length of processing time, with the increase of K2Cr2O7 concentration, the activity of SOD, CAT, GST in cell in-creased at first and then decreased; but the content of MDA decreased slowly at first and then increased rapidly. When the K2Cr2O7 solution concentration was constant, with the extension of treatment time, the activity of SOD, CAT, GST in cell showed an increasing trend; while the content of MDA decreased slowly. Potassium dichromate solution had certain toxic ef-fects on A. cepa cell, which may be related to regulating the activity and the content of various enzyme systems in cell.%研究不同浓度重铬酸钾溶液及不同处理时间对洋葱(A llium cepa L.)根尖细胞有丝分裂和植物保护酶系统的影响,旨在为探究重金属铬作用于植物体的生理生化机理提供参考.分别用0、12.5、25.0、50.0、100.0、200.0 mg/L重铬酸钾溶液处理洋葱根尖6、12、18、24 h,而后收集洋葱根尖组织,分别用于洋葱根尖组织石蜡切片、苏木素染色观察和测定根尖细胞中的超氧化物歧化酶、过氧化氢酶、谷胱甘肽-S转移酶活性及丙二醛含量.结果表明,不同浓度重铬酸钾溶液处理洋葱根尖不同时间后,细胞有丝分裂出现异常分裂,并伴有微核的产生;无论处理时间长短,随着处理浓度的增加,细胞中的超氧化物歧化酶、过氧化氢酶、谷胱甘肽-S转移酶活性都呈现先上升、后下降的变化趋势,而丙二醛含量先缓慢下降、后迅速上升;当处理浓度一定时,随着处理时间的延长,细胞中的超氧化物歧化酶、过氧化氢酶、谷胱甘肽-S转移酶活性呈上升趋势,而丙二醛含量呈缓慢下降趋势.说明重铬酸钾溶液对洋葱具有一定的细胞毒性作用,可能与调控细胞中各种酶系统的活性及含量有关.