Effect Of Cadmium Uptake By Rice And Its Response Of Silicon And Selenium

Based on the field plot experiment, this paper studied the law of Cd content in each organ of different varieties of rice planted in the field during the reproductive period. Through pot experiment, this paper discussed the effect of silicon and selenium fertilizer, which exerts an influence on the Cd content in each organ of different varieties of rice planted in the polluted areas of lead and zinc metallurgical industry. The main results of the experiment were as follow:(1) In the field plot experiment carried in Xiangyin Agricultural Research Institute, the law of the Cd content in each organ of different varieties of rice represents:root>stem>leaf, and the law of absorption and accumulation of Cd during different reproductive period is similar to the fact that the Cd content in rice root shows a trend of decreasing after the increase and increasing again, with the lowest in the seeding stage and the highest in the tillering stage; The trend of Cd content in stalks and lamina during different period represents something like the shape of letter "M", which decreases after the increase and increases again before the last decrease; The difference, which is not remarkable, exists in the capabilities of absorption and accumulation in the same parts of different varieties of rice. The Cd content in hulled rice of different varieties have differences, and the Cd content of Weiyou46have an obvious higher trend than other three varieties of rice. The Cd content in hulled rice of two varieties as Xinliangyou106and Xiangwanxian12are inferior to national hygienic standard for grains (0.2mg/kg), which can be the breeding seeds of rice varieties with low Cd accumulation;(2) In pot experiment, paddy rice, whether early or late, has increasing Cd content in every part as it grows, the Cd content of rice plants show a law of root>stem>leaf; Spreading silicon fertilizers and selenium inhibit the rice from absorbing Cd, and the inhibition of silicon fertilizer is much stronger than that of selenium; Spreading of silicon fertilizer can not only obviously prohibit root system of rice from absorbing of the Cd in the soil, but also strongly inhibit the accumulated Cd in the root system from transferring to the part above earth; With different fertilizing methods, the rice root system of the same category has different absorbing abilities of Cd. With identical fertilizing method, the Cd content of the same part differs as the rice categories differ, but the difference is subtle; in early rice experiment, after silicon fertilizer is spread to Jinyou974, the Cd content in the hulled rice are0.1135mg/kg, lower than the0.2mg/kg of national hygienic standard for grains; In late rice experiment, the spreading of silicon fertilizer lowers the Cd content in the hulled rice of Jinyou297which is0.1658mg/kg. Fertilizing silicon fertilizer improves the pollution control of rice Cd. Silicon, potassium K and calcium fertilizers decrease the action mechanism of rice to absorb Cd and hulled rice Cd content. May be the combination of silicon-cadmium and calcium-cadmium increases the pH value of the soil once again and lowers the mobility of Cd. Compared with silicon fertilizer, the handling effects of selenium are not as good, which may be related to the relatively small amount and the spreading methods. The amount of fertilizer spreading is to be researched.