硒对水稻的生态毒理效应及临界指标研究

通过土壤添加硒盆栽试验,研究了黄棕壤不同浓度Se对水稻生物量、叶绿素含量、抗氧化酶系统的影响.结果表明,低浓度Se(<8mg·kg^-1)对水稻根和地上生物量、叶绿素a含量、叶绿素a/b有促进作用,并整体提高了作物抗氧化酶系统,使MDA下降,SOD、CAT、POD、GSHPx活性相应提高.而高浓度Se(>16mg·kg^-1)对水稻根和地上生物量、叶绿素a含量、叶绿素a/b有明显的抑制作用,对抗氧化酶系统产生胁迫效应,使GSHPx明显上升,MDA上升,SOD、CAT、POD酶活性明显下降.各项生理指标与土壤Se处理浓度之间相关分析表明,土壤Se浓度与地上部干重相对百分率、根干重百分率、叶绿素a/b、MDA、SOD、CAT、POD之间有显著相关性.比较胁迫效应10%值的临界指标EC10值表明,作物地上部干重抑制率作为土壤临界值制定的依据更为可靠,EC10为21mg·kg^-1.

Eco-toxicological effects of selenium and its critical value on Oryza sativa

In a pot experiment with brown-yellow soil, this paper studied the effects of different concentration selenium on the growth and activated oxygen- scavenging system of Oryza sativa. The results showed that low concentration Se (< 8 mg x kg(-1)) had a promoting effect on the wheat biomass, chlorophyll a, chlorophyll a/b, and activated oxygen- scavenging system, while high concentration Se (> 16 mg x kg(-1)) was in adverse. Soil Se concentration had a significant correlation with root biomass, shoot biomass, chlorophyll a/b, MDA, SOD, CAT, POD. It was defined by the pot experiment that 10% inhibition rate of root or shoot biomass could be regarded as critical value, and the critical content of soil Se was estimated to be 21 mg x kg(-1).