液体有机肥对铅、镉污染下马铃薯重金属吸收及干物质积累的研究

采用盆栽实验,研究了Pb、Cd污染下,一种液体有机肥对马铃薯各器官Pb、Cd吸收量的影响及对马铃薯生长的缓解作用。结果表明:在基施液体有机肥作用下,马铃薯各器官对Pb、Cd的吸收具有明显差异,Pb和Pb、Cd复合污染条件下,马铃薯Pb、Cd吸收情况一致,即根叶茎块茎,而Cd污染下,马铃薯各器官吸收量变化规律为根茎叶块茎;马铃薯的根冠比、干物质累积量和单株产量随液体有机肥浓度增加而增加,且各处理均在有机肥高浓度时达到最大值;马铃薯块茎中Pb、Cd吸收量在研究范围内随有机肥浓度的增加而减少,块茎中Pb吸收量比未施加液体有机肥组降低34.7%,Cd吸收量比未施加液体有机肥组降低52.1%。综上认为在研究范围内,马铃薯底施液体有机肥对Pb、Cd污染均有较明显的缓解效应。Pb污染下块茎中的Pb含量均超标,Cd污染下,块茎膨大期块茎中的Cd含量全部未超标,块茎成熟期部分处理超标,可以通过适当提前收获,降低块茎的Cd吸收,达到安全标准。

Effects of liquid organic fertilizer on absorption of lead and cadmium and dry matter accumulation in different organs of potato

Controlling heavy metal pollution that is a potential threat to crop growth in soil has been a hot topic. In this study, the effects of liquid organic fertilizer on the absorption of lead and cadmium in different organs of potato and on plant growth were investigated in pot experiment. Under liquid organic fertilizer as basal fertilizer, there are significant differences in the absorption of lead and cadmium in different organs of potato. In lead and lead/cadmium pollution, lead and cadmium accumulation by different parts of potato was roots >leaves >stems >tubers, whereas lead and cadmium accumulation was roots >stems >leaves >tubers in cadmium pollution. The root/shoot ratio, the accumulation of dry matter and the yield of single potato plant were the maximum at the highest organic fertilizer rate. Applying liquid organic fertilizer decreased lead and cadmium uptake in potato tubers by 34.7% and 52.1%, respectively, as compared to the control. Lead concentrations in potato tubers did not exceed the standard under lead pollution. However, cadmium concentrations in the tubers exceeded the standard during tuber expansion period though tuber cadmium in some treatments fell below the standard at the mature stage. The present experimental results show that liquid organic fertilizer can reduce the content of lead and cadmium in potato, and that harvesting potato earlier might reduce cadmium uptake by potato tubers.