根表铁膜对水稻镉吸收的影响

Effects of iron plaque in root surface on cadmium uptake of rice

为了探明根表铁膜对水稻镉吸收的影响,首先从8个水稻品种中筛选出镉低累积品种(丙0203)和高累积品种(绍糯16-72),之后采用水培试验研究了根系活力(根系分泌物)变化与根表铁膜形成的关系,以及外源铁、镉对根表铁膜形成和水稻各部位镉吸收的影响。结果表明,0.05 mg·L-1 Cd处理24 h,绍糯16-72总的Cd吸收量是丙0203的1.73倍,并且绍糯16-72根、茎、叶各部位的镉累积量均显著(P<0.05)高于丙0203。在此基础上,外源添加铁后,绍糯16-72的镉累积量显著(P<0.05)降低,仅为丙0203的59%,且根、茎、叶中镉含量均显著(P<0.05)低于丙0203。温度试验(培养液温度分别为100℃、4℃和25℃)结果表明,水稻根表铁膜的形成与水稻根系活性密切相关,25℃下绍糯16-72的根系分泌物含量和铁膜含量均显著(P<0.05)高于丙0203。外源添加铁和镉后,绍糯16-72的根系活性、根表铁膜含量和铁膜中镉的吸附量增加,且上述指标的增幅均大于丙0203。以上结果表明,根表铁膜的形成可抑制镉向水稻体内迁移。研究结果为通过外源添加铁阻控水稻镉吸收提供了理论依据。

In order to elucidate the effect of the iron plaque on cadmium(Cd)uptake of rice,the Cd low-accumulation variety(Bing 0203)and high-accumulation variety(Shaonuo 16-72)were screened out of 8 test rice varieties first.Then,a series of hydroponic experiments were conducted to test the changes of root activity(root exudates),iron plaque formation,Cd content in iron plaque,and Cd uptake in different parts of rice.It was shown that the total Cd uptake of Shaonuo 16-72 was 1.73 times of Bing 0203 under 0.05 mg·L-1 Cd treatment after 24 h,and the Cd contents in roots,stems and leaves of Shaonuo 16-72 were significantly(P<0.05)higher than those of Bing 0203,respectively.On this basis,exogenous iron addition significantly(P<0.05)decreased Cd accumulation of Shaonuo 16-72 to 59%of Bing 0203.Accordingly,the Cd contents in roots,stems and leaves of Shaonuo 16-72 were significantly(P<0.05)lower than those of Bing 0203.Temperature experiments(100℃,4℃and 25℃)showed that the formation of iron plaque was related to the activity of rice root(root exudates).The contents of root exudates and iron plaque in Shaonuo 16-72 was significantly(P<0.05)higher than those of Bing 0203 at 25℃.Exogenous iron and Cd addition significantly(P<0.05)increased the root activity,iron plaque content and Cd content in iron plaque of Shaonuo 16-72,and the increase of these indexes in Shaonuo 16-72 was higher than that in Bing 0203.In conclusion,iron plaque formation restrained Cd uptake in rice,which provided theoretical basis for the prevention of Cd uptake in rice by iron application.