酸雨和降尘对植物产量及汞含量的研究

EFFECTS OF ACID RAIN AND DUSTFALL ON THE YIELD AND MERCURY CONCENTRATION OF PLANTS

采用盆栽试验，研究了模拟重庆现实酸雨（ｐＨ４．０）和降尘（３３．５ｔ／月ｋｍ２）对番茄产量和植株汞浓度分布的影响。结果表明，酸雨处理使钙质紫色土上的番茄增产２１．６％，并促进叶汞积累。降尘处理使酸性紫色土上的番茄增产１９．２％，并增加了根汞含量。酸雨和降尘复合处理较对照、酸雨和降尘处理分别减产３．０％～１６．１％，３．８％～３１．０％和１５．８％～１８．７％，叶汞浓度分别增加１２．８％～２５．４％，９．８％～１５．５％和１８．０％～２５．８％，但均未对果实汞积累产生影响。这不仅与酸雨促进降尘溶出汞，增加植物叶片细胞质膜透性有关，而且与土壤肥力和作物长势相关。

A pot experiment was conducted to investigate the effects of simulated acid rain (pH 4.0) and dustfall (33.5 t/month.km 2), which are similar to the actual acid rain an dustfall in the vinicity of Chongqing, on the yield of tomato ( Lycopericum esculentum Mill) and Hg distribution in the plants. Compared with the untreated control, acid rain treatment resulted in an yield increase of tomato by 21.6% and promoted Mg accumulation in the leaves on calcareous purple soil while dustfall treatment increased tomato yield by 19.2% and Hg concentration in the root on acid purple soil. The treatment of acid rain in combination with dustfall decreased yield by 3.0%～16.1%, 3.8%～31.0% and 15.8%～18.7%,and increased leaf Hg by 12.8%～25.4%,9.8%～15.5% and 18.0%～25.8%, resp., as compared with the control, acid rain treatment and dustfall treatment, but had no influence on Hg accumulation in the fruit. Such results are speculated to be related to the promoting efect of acid rain on Hg release and thus increasing the permeability of the membrane of leaf cells and to soil fertility and plant vigour.