不同镉浓度处理下水稻植株镉含量变化及其镉调控相关基因表达分析

以地上部镉含量不同的籼稻和粳稻品种各6个为材料,采用水培试验,设置6个镉浓度,研究了不同浓度镉处理对不同水稻品种植株生长、镉含量和相关重金属转运蛋白基因表达水平的影响。结果表明,镉胁迫对水稻生长有抑制作用,表现为苗高、地上部干物质量和叶绿素含量下降。在不同镉浓度处理下,植株根部和地上部的镉含量存在显著的基因型差异,植株中镉从根部向地上部的转运可能是水稻品种间以及籼粳亚种间地上部镉含量差异的主要原因,根部镉的吸收量影响较小。在0.50到2.00mg/kg的高镉处理梯度间,部分水稻品种地上部出现镉积累饱和现象(镉含量增加较少,部分水稻品种地上部镉含量甚至显著降低);在此镉浓度处理下,OsNRMAP1、OsIRT2和OsNAS2的表达水平显著上调,这可能与植株对镉的吸收调节作用相关。

Changes in Cadmium Concentration in Rice Plants Under Different Cadmium Levels and Expression Analysis of Genes Retated to Cadmium Regulation

Using six indica and six japonica cultivars, differed in cadmium concentrations in the above ground parts, the growth, heavy metal contents and expression levels of heavy metal transporter related genes were studied in a hydroponic experiment at six cadmium levels. Cadmium stress reduced plant height, shoot dry weight and chlorophyll content in rice leaves, inhibiting rice growth. Significant difference in cadmium content in rice roots and shoots among rice cultivars were found under different cadmium treatments, and the results showed that root to shoot translocation may be a key process that determine the difference in cadmium contents between rice cultivars and subspecies, while cadmium absorption by roots had little effect. At various cadmium levels (from 0.50 to 2.00 mg/kg), saturation of cadmium accumulation in rice shoots were found in some cultivars that cadmium content stopped increasing or even decreased. Besides, the expression levels of OsNRMAP1，OsIRT2 and OsNAS2 were significantly increased at such cadmium treatment, which might be attributed to the regulation of rice plants.