不同浓度硫处理下硒镉交互胁迫对水稻幼苗的生理特性影响

以淮稻6号为试验材料,采用水培的方法,研究了不同硫(S)浓度下(9、720mg·L-1)硒(Se)(5mg·L-1)和镉(Cd)(1、10mg·L-1)交互胁迫对水稻幼苗一些生理特性的影响,主要研究指标包括生物量、巯基物质含量和硒、镉含量。结果表明:(1)Cd对水稻幼苗各部分生长状况抑制能力大小不同,其对根长的抑制作用明显大于对茎长的抑制;(2)在无Se条件下,随着Cd浓度的增加,Cd对水稻幼苗生长的毒性不断增大,在加入一定浓度的Se后,Cd的毒性作用得到缓解;(3)在不同浓度S处理和Se、Cd交互胁迫下,随着S浓度增大,Cd对水稻幼苗毒性作用减轻;但高浓度的S处理反而对Cd与Se交互实验中Cd的毒性产生协同作用;(4)高浓度的S处理可以抑制水稻幼苗对Se的吸收;(5)巯基物质含量随着胁迫时间的增加呈先上升后下降的趋势。在Se、Cd交互实验中,低浓度S处理可以提高水稻幼苗中GSH和PCs的含量,从而促进植株体内重金属和PC的络合作用,缓减Cd对水稻幼苗的毒害。

Effects of Sulfur and Selenium Treatment on Plant Growth and Some Physiological Characteristics of Rice Under Cadmium Stress

Sulfur and selenium are important components in the defense system of plants.To better understand the interactions between sulfate and selenium in plant response to cadmium stress,changes in plant growth and the content of non-protein thiols(NPT,GSH,PC) were investigated in No.6 Huai rice seedlings grown hydroponically with Cd,with or without applications of sulfate and selenium.Results indicated that higher concentration of Cd(10 mg·L-1) caused decreases of plant growth,dry mass of rice seedlings and enhancement of Cd content in plant.As compared to the control,the higher concentration of S(720 mg·L-1) supply alone decreased Cd accumulation in rice due to the decrease of Cd availability and the alleviation effects of glutathione in rice as well as the a diminishing of the PC content.In presence of Se(5 mg·L-1) ,addition of 9 mg·L-1 exogenous sulfates to the medium significantly increased the plant growth,the content of non-protein thiols(NPT,GSH,PC) and clearly decreased the content of Se in rice seedlings as compared to that of Se and Cd treatment alone.A combination of Se(5 mg·L-1) -S(720 mg·L-1) treatment led to a decrease of rice plants size,dry mass and Se content,so did the content of non-protein thiols under cadmium stress.