Dynamic Characteristic Of Biological Validity Of Cd In Soil-Rice System

Pot experiment were conducted to study the differences and dynamics of Cdaccumulation among four different paddy rice varieties grown on the red earth and thepaddy soil in the Guangxi area,and the influence of Cd spiking on dry weightaccumulation, the chlorophyllâ…¡content, the soluble sugar content were discussed. Theobtained results were summarized as follows:1.Four different rice cultivars of dry weight accumulation presented rising asgrowth stages. Dry weight accumulation of the hybrids cultivars(Teyou1012.Peizataifeng) were higher than that of the normal cultivars(Zhenguiaiyihao.Fenghuazhan). Spiking 2.0mgCd/kg Cd stimulated the rice to accumulate dry weight,whereas Spiking 5.0mgCd/kg Cd inhibited the accumulation of dry weight, but, it wasnot obvious in the mature period.2.The chlorophyllâ…¡content was highest in Raises the flowering season,chlorophyllâ…¡content of the rice was seriously affected by Cd spiking, its contents wereapparently reduced with Cd spiking.3.The soluble sugar content presented reduced after rising, the contents werehighest in Raises the flowering season. Spiking 2.0mgCd/kg Cd stimulated the rice toaccumulate soluble sugar, whereas Spiking 5.0mgCd/kg Cd inhibited the accumulationof soluble sugar.4.The concentration of Cd in the part of rice was the hybrids cultivars higher thanthat of the normal cuitivars, the red earth was more beneficial to accumulated than the paddy soil.5.The rice varieties exhibited the genetic character on the Cd accumulation. The Cdcontents of the grains increased with Cd spiking in soil. Under the 2.0 mgCd/kgtreatment, the grain Cd went beyond the limit of the food health standards (0.2mg/kg).6.The dynamics of accumulate Cd increased up to a peak, and then decreased, thehighest content of Cd in the hybrids cultivars were early than that in the normalcultivars.7.The contents of available Cd of the red earth were higher than that of the paddysoil.8.The PAF (Accumulation coefficient of Cd) of hybrids cultivars were higher thanthat of the normal cuitivars, the PAF of different cultivars in the red earth were higherthan that in the paddy soil.