组配改良剂对土壤-蔬菜系统铅镉转运调控的场地研究

以组配改良剂LS(石灰石∶海泡石=2∶1)为试验材料,通过对湘南某矿区附近铅镉复合污染旱地土壤进行现场改良钝化,研究施加不同量的LS(0、2、4、8 g·kg-1)对茄子和苋菜植株吸收累积Pb和Cd的影响以及对Pb和Cd在2种蔬菜植株各部位间转运的调控.结果表明:1施加LS能够显著提高土壤p H,降低土壤中交换态Pb和Cd的含量.2施加LS能显著降低2种蔬菜植株各部位中Pb和Cd的含量.LS施加量为2~8 g·kg-1时,茄子果实中Pb和Cd的含量分别降低44.7%~78.6%和36.0%~78.7%;苋菜植株茎叶中Pb和Cd的含量分别降低45.8%~59.1%和40.0%~87.2%.3LS的施加降低了2种蔬菜植株各部位间Pb和Cd的转运系数.2种蔬菜植株在根-茎-果实间或根-茎叶间转运Cd的能力大于Pb,且施加LS各处理下,同种蔬菜相同部位对Pb和Cd的转运能力大小关系保持不变.

In-situ Study on Effects of Combined Amendment on Translocation Control of Pb and Cd in Soil-Vegetable System

An in-situ study aiming at remedying arid land complexly polluted with Pb and Cd by using combined amendment LS (a mixture of limestone and sepiolite with a ratio of 2 :1) was conducted in a mining area in southern Hunan, China. The main objectives of this study were to discuss the effects of LS application at different amounts (0, 2, 4, 8 g ·kg^-1) on the adsorption and accumulation of Pb and Cd in eggplant and amaranth, and to control the translocation and transportation of Pb and Cd among different parts of eggplant and amaranth. The results showed that: 1 Application of LS significantly increased soil pH values and decreased contents of exchangeable Pb and Cd in soil. 2 Application of LS led to an obvious reduction in contents of Pb and Cd in different parts of eggplant and amaranth. Compared with the control group, the contents of Pb and Cd in edible part of eggplant were decreased by 44.7%-78.6% and 36.0%-78.7%, and those reductions for amaranth were 45.8%-59.1% and 40.0%-87.2%, respectively, when the LS applying ratios ranged 2-8 g ·kg^-1. 3 Application of LS reduced the translocation factors of Pb and Cd among different parts of these two kinds of vegetables. The translocation ability of Cd among root, stem, and fruit (in eggplant) or leave (in amaranth) in these two vegetables was greater than that of Pb. However, application of LS with different amounts did not change the sequence of translocation factors of Pb and Cd among different parts of these two kinds of vegetables.