Genotypic difference in Zn- uptake and translocation at rice seedlings under different Zn2+ activity

Four genotypes of rice (IR8192, IR26, BY and Z921) with different Zn-efficiency were cultivated in chelator buffered nutrient solution at four Zn levels (pZn2+ i. e. -logZn2+) was 11.4,11.0,10.3,9.7, respectively to study the regulation of absorption, translocation and utilization of Zn at rice seedlings. As Zn2+ activity decreased, the amount of Zn uptake by rice seedlings decreased, while translocation rate of Zn from root to shoot, Zn utilization efficiency increased in all genotypes. There was obvious genotypic difference on changing range among four genotypes. At low Zn activity, Zn-efficient rice genotype (IR8192) was stronger in utilization efficiency of Zn and promoting the efficiency than Zn-inefficient(IR26) and Zn-dense in grain rice genotype (BY). At high Zn2+ activity, Zn-dense in grain genotype was stronger in Zn-uptake and accumulation in rice plant, maybe was one of the mechanisms of Zn-dense in grain genotype. It also could be concluded that nutrient traits of rice seedlings, such as total Zn uptake and accumulation in rice plant and could be used in screening Zn-dense in grain genotypes.