Effects Of Water Management On Cadmium Uptake In Rice Cultivars With Low Cadmium Accumulation

To explore the effect of water management on cadmium(Cd)content in rice,a pot experiment with 13 early-rice cultivars and 14 late-rice cultivars was conducted to study the effects of drought stress on grain Cd content in rice under different growth stage,including soil drying at tillering stage(I1),soil drying at booting stage(I2),soil drying at heading stage(I3),soil drying at milk stage(I4),and whole growth season flooding(I5).The key outcomes are as follows:(1)Water management had main effects on cadmium content and cadmium enrichment coefficient in early and late rice.Cultivar types of early-rice had main effects on cadmium content and cadmium enrichment coefficient,but cultivar of late-rice had not.There was an interactive effect between water management and early-rice cultivar,expect for late-rice cultivar.(2)Significant difference was observed in cadmium content and enrichment coefficient among water management,and both early-rice and late-rice was as following for I2>I3>I1>I4>I5.(3)The main effects of water management and growth stage as well as their interactive effects on soil available cadmium content in early and late rice were significant,as the order of early-rice following for I1>I4>I5>I2>I3 and heading stage > booting stage > milk stage > before transplanting > tillering stage,but as the order of late-rice following for I3>I2>I4>I1>I5 and before transplanting > milk stage > booting stage > tillering stage > heading stage.(4)The main effects of cultivar types and growth duration as well as their interactive effects on soil available cadmium content were significant.(5)Cadmium content in polished rice was significantly positive correlated with cadmium enrichment coefficient,with a high correlation coefficient of 0.994,and was significantly positive correlated with soil total and availible cadmium content before transplanting,available cadmium content of booting stage,with the Pearson coefficient being 0.403,0.448 and 0.505 respectively,but had obviously negative correlation with soil pH value before transplanting,available cadmium content of tillering stage and heading stage,whose correlation coefficients are-0.227,-0.574 and-0.500 respectively.