氮铅交互作用对小桐子生长及Pb累积的影响

Nitrogen-lead interaction and accumulation effects of lead on growth of Jatropha curcas L.

为了研究氮铅交互作用对小桐子幼树生长及重金属Pb累积的影响,设计3种施N水平(N0:0;N1:300 mg;N2:600 mg)、3种土壤Pb污染水平(Pb0:0;Pb1:500 mg;Pb2:1 000 mg)进行交互试验.结果表明:1不施N时,水平Pb1与Pb0差异不具有统计学意义,水平Pb2显著抑制了小桐子幼树生长及发育;随着施N量增加,Pb对小桐子的抑制作用降低,处理N2Pb2和N1Pb2的生物量分别比处理N0Pb2的提高了32.0%和8.1%.2施N时,各处理表土层5 cm的土壤硝态氮质量分数与表土层10和15 cm的相差无几,2次测定的土壤硝态氮质量分数中,处理N0Pb2和N1Pb2与其他处理相比各土层的土壤硝态氮质量分数变化幅度较小;施N降低了植物体内的含Pb量,并且提高了小桐子幼树的有效Pb提取量,处理N1Pb2和N2Pb2的有效Pb提取量分别比N0Pb2的提高了18.1%和27.9%.可见,施N量增加,显著减小了Pb对小桐子幼树的抑制作用,采用水平N2提高了水平Pb2污染土壤中小桐子幼树的生物量及有效Pb的提取量,使得修复效率得到了提高.

In order to study the interaction of nitrogen and lead and accumulation effects of heavy metal—Pb on Jatropha curcas L.,three nitrogen levels( N0: 0,N1: 300 mg,N2: 600 mg) and three kinds of soil lead pollution levels( Pb0: 0,Pb1: 500 mg,Pb2: 1 000 mg) are used for experiments.The results show that there is no statistical signification between Pb1 and Pb0 treatment,and the lead inhibits the growth and development of Jatropha curcas L. significantly,if no nitrogen fertilizer is applied. However,with the increase of nitrogen fertilizer,the inhibiting effect of lead on Jatropha curcas L. is relieved,the biomass of N1Pb2 and N2Pb2 is increased by 32. 0% and 8. 1% compared with the N0Pb2. After nitrogen fertilizer is used,the soil nitrate content is almost the same in 5,10 and 15 cmdeep soil layers. Additionally,the change of soil nitrate nitrogen content in N0Pb2 and N1Pb2 is smaller than the other treatments. This suggests the nitrogen fertilizer can reduce the amount of lead in the plants,and improve its effective extraction. For example,the effective extractions of lead in N2Pb2 and N1Pb2 are increased by 18. 1% and 27. 9%,respectively,compared with that of N0Pb2. Therefore,with the increase of nitrogen content,the inhibiting effect of lead on Jatropha curcas L. is decreased considerably,a high nitrogen content can increase the biomass of the plants and the effective extraction of lead,causing an improved restoration efficiency.