Effects Of Arbuscular Mycorrhizal Fungi On Growth And Cadmium Uptake Of Different Varieties Of Upland Rice

Rice crops is largest grain crop in China, its safety attracted widespread attention. To face the tense status of Chinese water resources, upland rice is expanding increasingly, thus its security issues can not be ignored. The soil heavy metal pollution is serious that caused by rapid development of social economy, cadmium(Cd) is most prominent especially. Because rice crops are easy to absorb and accumulate Cd, it is a serious threat to human health, therefore, it is imminent to study the how to reduce Cd uptake.Arbuscular mycorrhizal fungi(AMF) can form mutually beneficial symbiosis with plants, promote plants nutriants uptake, such as nitrogen(N) and carbon(C), improve their resistance to abiotic stress(such as salinity, floods, droughts, etc.) and affect the absorption and accumulation of heavy metals significantly. Therefore, this paper investigated the effects of two typical arbuscular mycorrhizal fungi(Glomus intraradices, Glomus mosseae, GI and GM) on the growth, Cd accumulation and rhizosphere soil enzyme(urease and invertase) activities of upland rice were investigated based on a soil pot trail under different Cd addition levels(0, 2, 10 mg·kg-1), in order to provide a scientific basis for practical application. The results revealed that:(1) Upland rice can colonized by AMF effectively under different concentrations cadmium treatment, their colonization rate of Cd treatment(0 mg·kg-1) was 72.81%~88.22% and 63.68%~93.89%, the highest and lowest colonization rate is Hanyou 3 colonized by GM and Zhonghan 221 colonized by GM; in the soil addition with 2 mg·kg-1 Cd, their colonization rates were 60.85%~77.19% and 52.66%~80.42%, the highest and lowest colonization rate is Hanyou 3 colonized by GM and Xinhanyou 26 colonized by GM; in the soil addition with 10 mg·kg-1 Cd, their colonization rates was 37.27%~55.97% and 29.14%~60.29%, the highest and lowest colonization rates is Zhenghan 9 colonized by GM and Zhonghan 221 colonized by GM. Fuethermore the colonization rates with different AMF treatment both decreased with the increase of Cd contents.(2) In the soil addition with 10 mg·kg-1 Cd, AMF colonization could help growth of rice, and relieve the inhibition of plant height under Cd stress. The inoculation treatment significantly improved all parts of upland rice. agents can effectively alleviate the inhibitory effect of Cd stress on the upland rice growing, Hanyou 3 colonized by GI increase rate to 22.7 percent, the stem biomass Hanyou 3 colonized by GM grain and Zhenghan 6 colonized by GM increase rate to 57.9% and 268% respectively.(3) Different AMF treatments have different effects on different Cd uptake of upland rice. with respect to the non-inoculated treatment, not added by Cd treatment, Hanyou 8 colonized by GI biggest grain Cd concentration decreased; at 2 mg·kg-1 Cd treatment, Hanyou 8 colonized by GM a reduction in grain Cd concentration maximum; at 2 mg·kg-1 Cd treatment, Hanyou 3 colonized by GI biggest grain Cd concentration decreased. Upland rice not only significantly increase the biomass, but also significantly reduce the amount of upland rice grain Cd accumulation is Hanyou 3 colonized by GI.(4) Compared with no mycorrhizal colonization, in a high concentration of Cd(10 mg·kg-1) stress Jinggangshan 1 colonized by GM rhizosphere urease activity of activated increase 35.1%. Zhenghan 6 colonized by GM drought on the 6th activation rhizosphere invertase activity increased as much as 59.8%. Thereby mycorrhizal colonization significantly carbon and nitrogen metabolisms in rhizosphere of upland rice compared with the nonmycorrhizal upland rice.