镉胁迫对不同水稻品种幼苗根系形态和生理特性的影响

Effect of cadmium on root morphology and physiological characteristics of rice seedlings

为了解植物根系对重金属镉的反应,以水稻秀水63和秀水09为试验材料,采用溶液培养方法,研究不同浓度镉(0、1、5、10、25、50、100μmol·L-1)对水稻幼苗根系形态和部分生理特性的影响。结果表明:1μmol·L-1镉处理对2个水稻品种根系生长有一定的促进作用,表现为植株干质量、根系总长度、根系表面积、根体积和根系活力均略有升高。但随着镉浓度(5～100μmol·L-1)增加,表现出一定的抑制效应,与对照相比,秀水63和秀水09分别在10μmol·L-1和25μmol·L-1镉处理时的根系干质量、根系总长度、根系表面积、根体积和根系活力明显受到抑制,而根系平均直径、质膜透性均有所增加。不同浓度镉胁迫对两个水稻品种直径≤1.5mm的根系生长影响最大,其中高于10μmol·L-1镉胁迫下,秀水63直径≤1.5mm根系长度、根系表面积和根系体积分别降低了11.89%～55.39%、10.77%～57.27%和18.37%～67.35%,秀水09分别降低了6.84%～40.48%、8.55%～42.79%和16.50%～52.42%。本实验结果表明,2个水稻品种对镉胁迫存在着一定的差异,秀水09对Cd胁迫的耐受能力要强于秀水63。

Cadmium （Cd） is one of the most toxic pollutants in the soil,which could limit plant growth and crop productivity. In order to explore the toxicity of cadmium to rice root,root morphology and physiological characteristics of two rice cultivars （Xiushui 63 and Xiushui 09） were studied with roots exposed to different Cd concentration （0、1、5、10、25、50、100 μmol·L^-1） in hydroponic culture. The results showed that a slight stimulatory effect on root growth was observed under 1 μmol·L^-1 Cd level,with slight increase in dry weight,total root length,root surface-area,root volume and root activity. However,with the increase in Cd concentration （10～100 μmol·L^-1）,an obvious decrease was found in dry weight,root length,root surface-area,root volume and root activity for Xiushui 63 and Xiushui 09 exposed to 10 and 25 μmol·L^-1 Cd,respectively,as compared with the control. In contrast,an increase in the average root diameter and relative permeability of plasma membrane was observed with the increase of Cd concentration. Roots with diameter≤1.5 mm of the two rice cultivars were affected significantly by different Cd concentration. Root length,root surface-area and root volume of roots with diameter≤1.5 mm for Xiushui 63 at Cd concentrations≥10 μmol·L^-1 decreased 11.89%～55.39%,10.77%～57.27% and 18.37%～67.35%,and those for Xiushui 09 were 6.84%～40.48%,8.55%～42.79% and 16.50%～52.42%. Based on the results of this study,we can conclude that there was genotypic difference in rice in response to Cd toxicity,and Xiushui 09 was more tolerant to Cd stress than Xiushui 63.