关键生育期施加外源锌灌溉水对水稻镉吸收转运的影响

Effects of the Application of Irrigation Water Containing Zn at the Key Growth Period on the Uptake and Transport of Cd in Rice

选取湖南省浏阳市某镉(Cd)污染稻田进行田间试验,研究水稻关键生育期(孕穗期和灌浆期)施加外源锌(Zn)灌溉水对土壤交换态Cd含量、孔隙水Cd浓度以及水稻各部位Cd吸收转运的影响.研究结果表明:(1)关键生育期施加外源Zn灌溉水可抑制土壤中交换态Cd向孔隙水的释放过程,土壤中交换态Cd含量与对照相比无显著差异,但成熟期土壤孔隙水Cd浓度显著降低16.7%~57.6%.(2)关键生育期施加外源Zn灌溉水可有效降低水稻各部位Cd含量;其中在孕穗期前和灌浆期前均施加含Zn 20mg·L^(-1)的灌溉水处理下(BF1),水稻根、茎和糙米Cd含量分别显著降低56.0%、83.8%和85.2%.(3)相较于施加含Zn 100 mg·L^(-1)的灌溉水,施加含Zn 20 mg·L^(-1)的灌溉水各处理显著降低水稻对Cd的吸收与转运,水稻根-茎之间的Cd转运系数(TF)降幅为12.5%~56.3%,其中B1和BF1处理下达到显著水平.上述研究表明,施加外源Zn灌溉水显著降低水稻对Cd的吸收积累,在孕穗期前和灌浆期前均施加含Zn 20 mg·L^(-1)的灌溉水可有效实现Cd污染稻田安全生产.

In this study,a field experiment was conducted to examine the effects of the application of irrigation water containing Zn at the key growth period(booting stage and filling stage)on exchangeable Cd content in the soil,Cd concentration in pore water,and Cd uptake and transport in rice in a Cd-contaminated paddy field in Liuyang City,Hunan Province.The results indicated that:①the application of irrigation water containing Zn during the key growth period could inhibit the releasing process of exchangeable Cd from the soil into pore water.Compared with that in the control,the content of exchangeable Cd in soil was slightly changed,but the concentration of Cd in soil pore water at the mature stage was significantly reduced by 16.7%-57.6%.②The application of irrigation water containing Zn at the key growth period could significantly reduce the Cd content in various parts of rice.Cd contents in root,stem,and brown rice with the application of irrigation water containing 20 mg·L^(-1) Zn before the booting and the filling stage(BF1)were significantly decreased by 56.0%,83.8%,and 85.2%,respectively.③Compared with the application of 100 mg·L^(-1) irrigation water containing Zn,the application of 20 mg·L^(-1) irrigation water containing Zn significantly reduced the uptake and transport of Cd in rice,and the translocation factor(TF)of Cd from rice roots to stems was also significantly reduced by 12.5%-56.3%,with the B1 and BF1 treatments reaching significant levels.These results suggested that the application of irrigation water containing Zn could significantly reduce the uptake and accumulation of Cd in rice,and the application of 20 mg·L^(-1) irrigation water containing Zn before the booting and filling stage could effectively realize the safe production of Cd-contaminated paddy fields.