不同蒸腾作用对番茄幼苗吸收Pb、Cd的影响

Effect of transpiration rates on the absorption of Pb and Cd in seedling of tomato

蔬菜中重金属污染是人们关注的热点问题之一,其中Pb、Cd的污染在我国种植蔬菜的土壤中较为突出,蔬菜对Pb、Cd的吸收除了受到土壤中Pb、Cd含量的影响之外,蔬菜本身的蒸腾作用是否会对吸收过程产生作用。通过在人工气候箱中,调节环境的温度和湿度,形成不同的环境蒸汽压,使植物产生不同的蒸腾作用,利用水培实验研究了在不同蒸腾作用下两个番茄品种(Lycopersicon esculentu,品种名分别为FA-189和合作903)的幼苗对重金属Pb、Cd的吸收富集规律。结果表明,高蒸腾作用下植株Cd和Pb含量比低蒸腾作用下分别增加了1.47～1.73倍和1.25～1.75倍,单株的积累量则分别增加了1.71～3.18倍和1.67～2.21倍。通过分析蒸腾水量对吸收Pb、Cd的影响,表明番茄幼苗通过蒸腾作用拉力吸收进入体内的重金属的量占总吸收量的比例极小,一般在0.0008%～0.2%之间,说明番茄幼苗对Pb和Cd的吸收主要为代谢吸收。同时在比较了番茄对Pb和Cd的被动吸收比例时,发现Pb较Cd的比例要高几倍到几十倍,说明番茄对Pb和Cd的吸收富集规律可能存在不同的机理。

The contamination of heavy metals in vegetable is one of the hotspot people focus on, as the Pb and Cd pollution in the soil of plant vegetables in China are serious. Besides the contents of Pb and Cd in soil affect that in the vegetables, whether the transpiration rate also influence the absorption of heavy metals by vegetables？ In order to indicate the influence, the method of solution culture was carried out, the accumulation regularity of Pb and Cd by the seedlings of two kinds of tomatoes （Lycopersicon esculentu, FA-189, Hezuo903） were studied. The results indicated that with the increase of transpiration rate the absorption of Pb and Cd increased, and the accumulation of the heavy metals in individual plant under high rate were increased than low rate by 1.67-2.21 times and 1.71-3.18 times respectively. Study on the effect of transpiration water consumption on the absorb of Pb and Cd by seedling of tomato, a result can be drown that transpiration pull had tiny effect on the absorption of heavy metals, the proportion were between 0.000 8% and 0.2%, indicated that the absorption of Pb and Cd by seedling of tomato was mainly through the metabolic absorption.