Pb对农作物的生理生态效应

Eco-physiological Response of Several Crops to Lead

采用温室砂培盆栽试验,对小麦、玉米、水稻、油菜4种作物体内的含Pb浓度、硝酸还原酶的活性、可溶性糖的含量及叶绿素的含量作了研究。结果表明,随着Pb离子浓度的增高,小麦、水稻的茎叶和根系含Pb量也增高,在1000mg·L-1浓度下含Pb量达高峰,而油菜和玉米体内Pb的含量先增加后降低。小麦和水稻根系中的含Pb量高于茎叶中的含量,而油菜和玉米根系中的含Pb量低于茎叶中含量。低浓度的Pb处理能够促进植物正常的生理代谢活动,如茎叶内硝酸还原酶活性(NO2-,μg·g-1,FW)、可溶性糖的含量、叶绿素的含量均有不同程度的增加,但随着Pb离子浓度的增加,其促进作用变为抑制作用,高浓度严重阻碍作物正常的生理活动,表现症状为叶片黄化失绿、茎叶萎蔫。

To research eco-physiological response of crops to lead (Pb),the uptake and distribution of lead, the activity of nitric acid reverting enzyme (NR),the contents of soluble sugar and chlorophyll of four crops (wheat, maize, rice and cole) were employed in this study. 7 lead concentrations were used including 0,50,100,200,400,800,1 000 mg·L-1, respectively. The results have shown that the lead contents in the above-ground parts and root of wheat and rice were risen up straightly till a climax with the treatment of 1 000 mg·L-1.On the other hand,the lead contents trended in the other two plant species was ascending in the first and then falling at the last. It may be concluded that low concentration of lead could stimulate the activity of physiological metabolism in the crops,but this positive effect may alter to negative damage for the crops under high concentration with lead treatment.