摘要
A pot experiment with exogenous cadmium was utilized to study the effects of waterlogging time on rice yield and Cd accumulationin different growth stages including top tillering stage and filling stage.The results showed that the rice yields of all flooding treatments were lower than the CK(CI).The WI,T1,T2,T3 and T4 decreased significantly by 23.7%,16.0%,15.5%,20.2%and 18.6%respectively.The Cd content of brown rice decreased with the extension of waterlogging time.And WF was the lowest,at only 3.4%of the wet irrigation of the whole growth period(WI).Under the same waterlogging condition,the Cd content in brown rice with 1 to 4 weeks of flooding treatment at the top tillering stage decreased by 27.1%(P﹤0.05),46.6%(P﹤0.05),56.0%(P﹤0.05)and 35.2%(P﹥0.05)respectively,compared with the treatment at the filling stage.And the average decrease was 41.2%.The variation tendency of Cd content in stems and leaves was similar to brown rice.The translocation efficiency of Cd from stems and leaves to rice seeds decreased with the extension of waterlogging time.The Cd enrichment factor of stems and leaves,as well as brown rice,varied greatly with different treatments.Specifically,the Cd enrichment factors in brown rice and in stems and leaves under WI were 28.0 and 17.8 times higher respectively than those under WF.The findings of this study demonstrated that flooding could inhibit the uptake and accumulation of Cd in rice,with significant positive correlation between them.The inhibition effect of flooding treatment on Cd accumulation in rice at the top tillering stage was superior to that at the filling stage.
采用盆栽试验方法,以外源添加镉模拟土壤镉污染,研究了水稻不同生育期(分蘖盛期和灌浆期)淹水以及淹水时间对水稻产量及吸收累积Cd的影响。结果表明,与常规灌溉处理(CI)相比,其他不同淹水时间处理均出现一定程度减产,其中全生育期湿润灌溉(WI)、分蘖盛期开始淹水1～4周(T1、T2、T3和T4)5个处理的水稻产量显著下降,降幅分别为23.7%、16.0%、15.5%、20.2%和18.6%。随着淹水时间的延长,糙米Cd含量呈下降趋势,其中以全生育期淹水处理(WF)的糙米Cd含量最低,仅为全生育期湿润灌溉处理(WI)的3.4%。在相同淹水时间条件下,分蘖盛期开始淹水1～4周处理的糙米Cd含量较灌浆开始淹水1～4周处理的分别降低了27.1%(P<0.05)、46.6%(P<0.05)、56.0%(P<0.05)和35.2%(P>0.05),平均降幅为41.2%。水稻茎叶Cd含量与糙米Cd含量的变化趋势基本相同。水稻茎叶对Cd的转运效率随淹水时间的延长呈下降趋势。不同处理的水稻茎叶和糙米Cd富集系数变异极大,其中全生育期湿润灌溉处理(WI)和全生育期淹水处理(WF)相比,糙米Cd富集系数相差28.0倍,茎叶Cd富集系数相差17.8倍。可见,淹水能有效抑制水稻对Cd的吸收累积,这种抑制效果与淹水时间呈正相关,且分蘖盛期淹水对水稻茎叶和糙米Cd累积的抑制效果优于灌浆期淹水。
基金
Supported by Hunan Key Research and Development Program of Agricultural Technology Innovation(2016NK2190)
National Key Research&Development Project(2016YFD0800705)
Specialized Scientific Research in Public Welfare Sector Water Resources Ministry(201501019)~~
