硅对镉胁迫下水稻幼苗培养液指标及其生物量的影响

Effect of Cadmium Stress by Silicon on Some Indicators of the Cultivation and Biomass of Oryza sativa L. Seedlings

通过溶液培养,研究不同浓度Si(0、30、80、130、180mg·L-1SiO2)在4.0mg·L-1Cd2+浓度胁迫下对水稻幼苗培养液中的Si、Cd含量、pH值及其下降值、根系细胞K+外流量和根、茎叶干重的影响。结果表明,大量的Si可通过在水稻体外(培养液中)与Cd相结合,形成了Si-Cd络合物,从而束缚了Cd的活性,使培养液中有效Cd含量明显下降,降低了Cd对水稻幼苗的毒性,最终抑制水稻对培养液中镉的吸收。此外,随着培养液中SiO2浓度的加入,根系细胞K+外流量极显著(P<0.01)降低,培养液中的pH值下降,说明Si可以减轻Cd对水稻根系细胞质膜的伤害,使细胞质膜透性下降,从而保护了水稻细胞膜不受Cd的破坏,进而增加了水稻幼苗根、茎、叶的生物量。

The effect of silicon on some indicators of the culture solution and biomass of Oryza sativa L. seedlings under cadmium stress was studied by hydroponic culture method.The Oryza sativa L. seedlings at the Cd^2＋ concentrayion of 4.0 mg· L^-1 were treated with SiO2 at 0,30,80,130,180mg· L^-1 concentrations respectively. The results showed that a large number of Si combined with Cd to form Si-Cd complex in vitro （culture solution）, therefore dampening the activity of Cd. The effective Cd in the solution was significantly decreased. In addition, as the increasing of SiO2 concentration, the flow of K^＋ in root cells was significantly decreased （P〈0.01）, pH was also decreased. Those indicated that Si could reduce the cell membrane damage caused by Cd, decrease the cell membrane permeability, then increase the biomass.