叶面阻控剂对黔中喀斯特地区水稻Cd富集特征的影响

为优选适用于贵州喀斯特地区Cd污染农田水稻生产的叶面阻控剂,在贵州中部典型Cd超标稻田开展田间试验,于水稻分蘖期、抽穗期喷施不同叶面阻控剂作为处理(编号分别为SI、SE、GWY、FE、ZN),以不施叶面阻控剂的处理为对照(CK),在成熟期采集水稻植株样品,探讨不同叶面阻控剂对水稻各部位Cd迁移转化的影响。结果表明:与CK相比,喷施叶面阻控剂对土壤pH、有机质、Cd含量无显著影响。SE、GWY、ZN、SI处理下,水稻产量分别较CK显著(P<0.05)增加13.56%、5.77%、5.74%、7.30%。与CK相比,ZN处理下糙米镉含量降幅最大(56.5%),其次是SE、GWY处理,降幅分别为52.3%和39.4%。与CK相比:SE处理下,水稻茎节的Cd富集系数下降44.8%;ZN处理下,水稻穗轴、糙米中的Cd富集系数分别下降55.0%、58.0%;SI处理下,水稻叶的Cd富集系数提高133.7%。SE、SI处理下,枝梗-稻壳的Cd转移因子分别较CK降低65.8%、40.8%。综上,SE、GWY、ZN能提高水稻产量,降低糙米中的Cd含量,调节Cd在水稻植株各部位的富集与转运,可以用作保障黔中地区Cd污染耕地安全利用的水稻叶面阻控剂。

Effects of foliar control agents on cadmium enrichment characteristics of rice in karst area in central Guizhou

To screen suitable foliar control agents for rice production on Cd contaminated soil in karst area of Guizhou, field experiments were carried out in typical paddy fields with excessive Cd in central Guizhou. Five foliar control agents were sprayed at tillering and heading stages as treatments, denoted as SI, SE, GWY, FE, ZN, respectively, with no foliar control agent applied as control (CK). Rice plant samples were collected at mature stage to explore the effects of foliar control agents on Cd migration and translocation in various parts of rice. It was shown that application of foliar control agents had no significant effect on soil pH, organic matter and Cd content. Under the treatment of SE, GWY, ZN and SI, the rice yield was significantly (P<0.05) increased than that of CK by 13.56%, 5.77%, 5.74% and 7.30%, respectively. Compared with CK, the highest reduction rate of Cd in brown rice was found under Zn treatment (56.5%), which was followed by the treatment of SE (52.3%) and GWY (39.4%). Compared with CK, the enrichment coefficient of Cd in stem nodes was decreased by 44.8% under SE treatment; the enrichment coefficient of Cd in panicle axis and brown rice was decreased by 55.0% and 58.0%, respectively, under ZN treatment; the enrichment coefficient of Cd in leaf was increased by 133.7% under SI treatment. The Cd transport coefficient from branch to rice husk was decreased by 65.8% and 40.8% under the treatment of SE and SI as compared with CK. In conclusion, the treatment of SE, GWY and ZN could increase rice yield, decrease Cd content in brown rice, and regulate the enrichment and transport of Cd in various parts of rice plant. Thus, these foliar control agents could be used to safeguard the utilization of Cd-contaminated cultivated land in central Guizhou.