镉对油菜幼苗生长及微量元素含量的影响

通过营养液培养,重点研究了不同浓度镉（Cd）胁迫下,中双9号冬油菜（Brassica napus L.）幼苗体内生理生化及微量元素（Fe、Mn、Zn、Cu）含量的变化特征,目的是进一步阐明Cd胁迫对油菜生长产生毒害的作用机理。结果发现,Cd胁迫显著抑制了油菜幼苗的生长,植株根系和地上部干重随着Cd浓度的升高而显著降低;油菜幼苗叶片中光合色素含量也随着Cd浓度的升高而显著降低;油菜幼苗根系和地上部4种微量元素浓度也随着Cd浓度的升高发生了显著变化;同时,油菜幼苗体内抗氧化酶（SOD、POD和CAT）活性随着Cd浓度的升高表现出先显著升高后显著降低的趋势。这些结果表明,外源Cd胁迫通过降低油菜幼苗光合色素含量、抑制植株光合作用,引起幼苗体内养分代谢紊乱,诱导产生氧化胁迫等抑制了油菜幼苗的生长。研究还发现,中双9号油菜幼苗地上部Cd浓度和Cd富集量显著低于根系,中双9号应该属于低吸收Cd的冬油菜品种。

Influences of Cadmium on the Growth and Micro-elements Contents of Oilseed Rape Seedlings

In order to elucidate the mechanisms of cadmium（Cd） stress on plant growth,a hydroponic experiment was conducted to investigate the influences of Cd on the growth,physiological properties and micro-elements contents of oilseed rape（Brassica napus L.cv.Zhongshuang 9）seedlings.Present study included 0,0.1,0.2,0.5 and 1.0 mg·L-1 Cd treatments（CK,C1,C2,C3 and C4,respectively）with four replicates.Results showed that,compared with CK,both roots and shoots dry weights of oilseed rape seedlings were significantly decreased with Cd concentrations increasing in hydroponic solution.The photosynthetic pigments contents,compared with CK,were also significantly decreased with Cd concentration increasing.Except the Cu concentrations in roots,the concentrations of micro-elements in both roots and shoots of plants were significantly decreased by Cd addition in hydroponic solution,compared with CK.While,the antioxidant enzymes（SOD,POD and CAT）activities were increased at the lower Cd concentrations and then decreased at the higher Cd concentrations in hydroponic solution.These results indicated that,exogenous Cd stress significantly decreased the growth of oilseed rape seedlings through inducing the photosynthetic pigments degradation,nutrient elements metabolism disturbance and oxidative stress on plants.Meanwhile,the Cd concentrations and accumulations in the shoots of oilseed rape seedlings were significantly lower than those of plant roots,which indicated that Zhongshuang 9 might be a lower capacity cultivar for Cd uptake.