水稻不同品种对Cd吸收累积的差异和机理研究

DIFFERENCES ON Cd UPTAKE AND ACCUMULATION AMONG RICE CULTIVARS AND ITS MECHANISM

采用盆栽和水培试验研究了华南地区水稻（Ｏ．Ｓａｔｉｖａ）的主要品种对Ｃｄ吸收累积的差异和引起差异的原因。盆栽试验结果表明，供试的２０多个品种生长在同一污染土壤上，汕优６３、汕优６４等杂交稻，产量较高，但糙米Ｃｄ含量也较高；野奥丝苗、增城丝苗、黑糯等优质稻糙米重金属含量较低；常规稻则变幅较大。作物品种间差异可达１倍以上。在同一Ｃｄ浓度和营养液配方条件下的水培试验显示，与汕优６３相比，糙米Ｃｄ含量较低的野奥丝苗其单位产量的耗水量、根冠比、Ｃｄ向糙米的迁移率明显较低。而且Ｃｄ向糙米的迁移率二者相差１倍多，汕优６３为３８．４％，野奥丝苗为１６．２％。

Cadmium uptake and accumulation for some rice ( Oriza sativa )cultivars in South China were studied with pot experiment and hydroponic crop.The mechanism resulting in the differences among cultivars was also studied.Results with pot experiments showed that,among more than 20 cultivars grown on the same contaminated soil,the hybrids such as Shanyou 63,Shanyou 64 harvested a higher yield and Cd content in husked rice was also higher.The high consuming quality cultivars such as Yeaosimiao,Zengchengsimiao and Heinuo,resulted in a lower Cd content in husked rice.The normal cultivars varied more greatly on yield and Cd content.The Cd content in high accumulating cultivars was more than 2 fold higher than that of the low accumulating cultivar.Under the same hydroponic crop conditions,the low accumulating cultivar,Yeaosimiao,showed less water consumption per gram of yield,lower ration of roots to aerial parts and lower Cd translocation rate to grains than the high accumulating cultivar,Shanyou 63。The Cd translocation rate for the high and low accumulating cultivars was 38 4% and 16 2% respectively,more than 2 fold of differences.This is maybe the most important factor causing the differences among the rice cultivars on the Cd accumulation.