水稻不同品种对铅吸收、分配的差异及机理

为探究水稻不同品种对Pb吸收积累的差异及机理，以20个不同基因型水稻品种(系)为材料，采用盆栽方法，研究了Pb在水稻植株各器官中的分配及在籽粒中的分布．结果表明，不同品种间，Pb积累量存在显著差异，但品种间的这种差异与品种类型关系不明显；不同器官、不同生育时期，Pb积累量和积累速率不同；各器官Pb浓度按根、茎、叶、穗、籽粒的顺序大幅度下降，分配到籽粒中的Pb比例很低；根与茎，茎与叶片、穗(抽穗期)、籽粒Pb含量呈极显著负相关；根与叶、穗(抽穗期)、籽粒，叶与穗(抽穗期)、籽粒的Pb含量呈正相关，相关性大多达极显著或显著水平；不同品种抽穗期叶片与成熟期籽粒间的Pb含量达显著正相关；Pb在稻米加工各产物中的分布很不均匀，稻谷经脱壳及精加工1次(2min)后，精米Pb含量仅为籽粒总含Pb量的32．88％．

Difference of lead uptake and distribution in rice cultivars and its mechanism

In order to investigate the uptake of lead by rice plant and the distribution of lead in different parts of rice, pot experiment was conducted with 20 rice cultivars of different genotypes by adding lead to soil. The results showed that there existed significant differences among the cultivars in the lead uptake and distribution by rice plants, but the differences had no obvious relationship with rice genotypes. The lead concentrations decreased rapidly from roots to grains along rice plants, so the concentrations of lead were very low in grains compared with other parts of rice plants. The regression analysis showed that there were significant negative correlations between adjacent organs of rice plant, but positive correlations, mostly significant, between disconnected organs, for the lead concentrations in them. Lead concentration in the leaf of heading stage showed a significant positive correlation with that in the grain of ripening stage. Lead was not distributed uniformly in different parts of grain structure, and the lead accumulation in polished rice was only 32.88% of the total lead accumulation in grain.