根表铁膜对水稻铅吸收转运的影响

通过温室土壤盆栽试验研究不同生育期水稻根表铁膜形成对水稻吸收和转运Pb的影响。结果表明,两种水稻根表铁膜形成量(以DCB-Fe含量计)及铁膜中吸附的Pb量均随着生育期的延长而减少。水稻根表铁膜Fe含量与铁膜吸附的Pb量呈显著的正相关关系(r=0.798,p0.01)。水稻根系和茎叶吸收积累Pb随着不同品种和不同生育期而变化。品种NK57籽粒Pb含量显著高于品种YD6,前者为后者的1.9倍。从富集系数和分配比率来看,Pb主要富集在水稻的铁膜和根系中,而积累在茎叶和籽粒中的比率较少。Pb从水稻根表铁膜、根系和茎叶向籽粒中的转运系数在两个水稻品种间差异均不显著。水稻分蘖期和孕穗期根表铁膜量与根系Pb含量均呈显著的正相关关系(p0.05),但是成熟期水稻根表铁膜量与根系、茎叶和籽粒中Pb含量相关性均不显著,说明根表铁膜形成对水稻分蘖期和孕穗期吸收积累Pb有一定影响,但对水稻成熟期根系、茎叶和籽粒吸收积累Pb影响不大。

Influence of Iron Plaque on Pb Uptake and Translocation by Rice(Oryza sativa L.)

Influence of iron plaque on root surface at different growth stages on Pb uptake and translocation by rice (Oryza sativa L.) was investigated in pot experiment. The results showed that the amount of iron plaque (DCB-extractable Fe) and Pb concentration in iron plaque decreased with the increase of growth stages. There was a significant positive correlation between Fe and Pb concentration in iron plaque (r=0.798, p<0.01). Pb concentrations in shoot and root varied with different rice cultivars and growth stages. Pb concentration in grain of NK57 was significant higher than that of YD6, and about 1.9 times of YD6. As for Pb bio-accumulation factor and distribution ratio, Pb mainly accumulated in iron plaque and root of rice, and less in shoot and grain. There was no significant difference between two rice cultivars for Pb translocation from iron plaque, root and shoot to grain. There was a significant positive correlation between amount of iron plaque and Pb concentration in root at tillering stage and booting stage (p<0.05), but no significant correlation between amount of iron plaque and Pb concentration in root, shoot or grain at mature stage, indicating that the formation of iron plaque on root surface partly affected Pb accumulation in root at tillering stage and booting stage, but there was no significant effect on pb accumulation in root, shoot and grain at mature stage.