高氯酸盐和铬复合污染对水稻生理特性的影响

Effect of the combined pollution of perchlorate and hexavalent chromium on physiological characteristics of rice

通过盆栽试验,研究了不同浓度高氯酸盐(ClO4-)、六价铬(Cr6+)及其复合污染(ClO4-+Cr6+)胁迫条件下水稻叶片叶绿素荧光参数、叶绿素含量和水稻体内抗氧化酶活性及丙二醛含量的变化。结果表明,随着ClO4-、Cr6+和ClO4-+Cr6+处理浓度的升高,水稻叶片叶绿素荧光参数Fv/F0、Fv/Fm和叶绿素含量均明显下降,且生长前期下降程度高于后期;ClO4-、Cr6+及ClO4-+Cr6+均可显著提高水稻体内POD酶(peroxidase)、CAT酶(catalase)活性和MDA(malondialdehyde)含量,且复合处理显著高于单一处理;分蘖期水稻体内SOD酶(superoxide dismutase)活性随着污染物浓度的增加明显降低,而在抽穗期其SOD酶活性升高。复合处理对水稻的损伤和毒害作用比单一处理更为严重,其交互作用机理值得进一步研究。

A pot experiment was conducted to study the stress effects of different concentration levels of perchlorate（ClO4^-） and hexavalent chromium（Cr^6＋） as well as their combination（ClO4^-＋ Cr^6＋） upon the changes of chlorophyll florescence parameters,antioxidant enzyme activity,and chlorophyll and malondialdehyde（MDA） contents of leaves of rice.Results showed that an increase in ClO4^-,Cr^6＋,and ClO4^-＋ Cr^6＋ concentrations decreased the chlorophyll florescence and chlorophyll contents of leaves significantly.Such a decrease was higher in the earlier than in the later growth stage of the rice.Both single treatment and combined treatment enhanced the peroxidase（POD） and catalase（CAT） activities and increased MDA contents in leaf.The activities of POD and CAT and the contents of MDA were higher for the ClO4^-＋ Cr^6＋ combined treatment than for the individual ClO4^-or Cr^6＋ treatment.As the pollution of perchlorate and hexavalent chromium increased,the superoxide dismutase（SOD） activity decreased in the tillering phase but increased in the heading stage.Toxicity and injury of the ClO4^-＋ Cr^6＋ combined treatment were higher than that of individual ClO4^-or Cr^6＋ treatment.Interaction mechanism of perchlorate and chromium pollution on rice were warranted for further study.