高氯酸盐对水稻生理生态的影响及其在稻田系统中的分布规律

Effect of Perchlorate on Rice Eco-physiological Characteristics and It′s Distribution in the Paddy Field System

本文通过盆栽试验在水稻整个生育期每周两次定量灌溉含有高氯酸盐的水,研究了3种浓度的高氯酸盐对水稻生长、生理指标的影响以及高氯酸盐在水稻-土壤系统中的分布规律。结果表明,持续分次加入0.1mg·L-1和50mg·L-1浓度的高氯酸盐对水稻的株高和分蘖数没有不利的影响。0.1mg·L-1浓度处理组的SOD、POD酶活性与对照组相比无显著性差异,而50mg·L-1浓度处理组的SOD、POD酶活性明显高于对照组和0.1mg·L-1浓度处理组;0.1mg·L-1浓度处理组的CAT酶活性与对照组相比也无显著差异,而50mg·L-1浓度处理组的CAT酶活性明显低于对照组和0.1mg·L-1浓度处理组;MDA含量随着污染物处理浓度的增加先上升后下降,两种浓度的高氯酸盐处理组与对照组相比都有显著性差异;高氯酸盐对水稻合成蛋白质有显著的促进作用,对水稻叶绿素含量的影响不显著。水稻叶片是高氯酸盐积累的主要器官,其ClO4-含量明显高于根、茎和谷,而且随着环境中高氯酸盐浓度的增加,水稻吸收并进入各部位的量也增加。水稻的根、茎、叶和谷中都不同程度地检测出ClO4-及其中间代谢产物ClO3-的存在,但土壤中则未检测出ClO4-和ClO3-,说明加入的ClO4-很少被土壤吸附并能很快被植物吸收或微生物降解。本实验中水稻各部位所含的氯酸盐都很少甚至未检出,说明中间代谢产物氯酸盐在水稻中相对容易被分解代谢。水稻品种不同,吸收积累高氯酸盐的量也存在差异,其中桂农占的籽粒积累高氯酸盐的量比其他品种多。

A rice culture pot experiment was conducted to study the effects of different concentrations of perchlorate in irrigation water on the growth and physiological activities of rice. The distribution of the added perchlorate in the soil-rice system was also studied. The results show that there were no significant effects on plant height and tiller number of rice with 0.1 and 50 mg·L-1 perchlorate in irrigation water. There were no significant differences of peroxidase（POD） and superoxide dismutase（SOD） activities between 0.1 mg·L-1 perchlorate in irrigation water and the control. However, 50 mg·L-1 perchlorate in irrigation water could increase POD and SOD activities in leaf. The catalase（CAT）activities in the 50 mg·L-1 treatment were significantly lower than in the control and in the 0.1 mg·L-1 treatment. However, there were not significant differences in CAT activities between the 0.1 mg·L-1 treatment and the control. Malondialdehyde（MDA） content in rice increased significantly with the increase of concentrations of pollutant. Perchlorate could promot protein synthesis in rice significantly, and it′s influence on chlorophyl contentl of rice was not significant. Concentrations of perchlorate in rice leaves were significantly higher than in root, stem or grain. It indicated that rice leaves was the main organ for perchlorate accumulation. The higher the concentration of perchlorate in irrigation water, the more perchlorate was absorbed by rice and entered into rice. Perchlorate and it′s intermediate metabolites chlorate could be detected in the root, stem, leaf or grain in all 4 varieties of rice in this experiment, but could not be detected in soil during harvest time. It indicated that added perchlorate inirrigation water had been absorbed by plants or degraded by microorganism in soil. In this experiment, the amount of chlorate detected was either in a very small amount or not able to be detected at all in different plant parts. It indicated that intermediate metabolite of chlorate is relatively easy to be catabolized. There was significant different among different varieties of rice in absorbtion and accumulation of perchlorate. The concentration of perchlorate in grain from variety Gui Nong was the highest among the 4 varieties.