Effects Of Zinc And Selenium On Growth And Cadmium Accumulation Of Rice Under Cadmium Stress

Cadmium(Cd),a heavy metal element with strong mobility and high biological toxicity,released into the environment rapidly by human activities such as mining for metal,smelting zinc,the overuse of chemical fertilizers and so on,can cause harm to human body through the food chain.It is easy for rice to accumulate Cd,so how to alleviate the cadmium toxicity of rice is a research hotspot in academic circles.Zinc(Zn)and selenium(Se)are essential micronutrients and beneficial microelements for the development of organisms.In plants,Zn and Se can interact with cadmium to a certain extent.However,there is no clear conclusion on whether the effect is antagonistic or synergistic,and there are few studies on the effect of interaction of zinc and selenium(Zn-Se)on Cd toxicity in rice.Therefore,through germination test and hydroponic test,this paper discussed the effects of Cd on the growth and development of rice,compared the effect of Cd toxicity mitigation and mineral element accumulation in Zn,Se and Zn-Se in Cd stressed rice.The main research results are as follows:(1)The low and medium concentrations of Cd stress can promote the germination of rice seeds,but high concentrations of Cd seriously inhibit it.Zn can alleviate cadmium toxicity and improve germination indexes of rice seeds.High concentration of Se can inhibit the germination of rice seeds.Zn-Se can alleviate Cd toxicity and promote rice seed germination to a certain extent.(2)In terms of the Cd concentration kinetic,adding Zn and Se can decrease the absorption rate of Cd and increase the affinity of rice roots to Cd.In terms of the time dynamic of Cd,adding Zn,Se and Zn-Se can inhibit the accumulation of Cd in rice obviously after 20 h.For different concentrations of Zn and Se,Se can reduce the transport of Cd from roots to aboveground parts,and Zn can promote the transport of Cd in rice.(3)Cd treatment inhibited rice growth,reduced root length,plant height,relative water content and chlorophyll content.Zn and Se can alleviate the Cd toxicity of rice,but Zn-Se can’t alleviate the Cd toxicity,and may aggravate the toxicity.Cd reduced the transport of P and Mn from roots to aboveground parts,increased the transport of K,Mg,Ca and Mo.Zn and se could alleviate the abnormal transport of K and Mg under Cd stress and reduce the transport amount.There is a positive correlation between Ca and Mg,Zn and Cu in rice plants.There is a positive correlation between Cd and Fe with Cd stressed rice.Cd stress can interfere with the distribution of ions in different parts of rice,while Zn and Se treatment can maintain the homeostasis of ions and resist the interference in rice.Cd can inhibit rice germination and growth,make leaves lose green and plants dwarf.Zn can slightly alleviate the cadmium toxicity in rice,but can’t reduce the accumulation and transport of Cd in rice.Se can not only alleviate the cadmium toxicity,but also reduce the accumulation of Cd.ZnSe can’t be used to alleviate cadmium toxicity in rice.