Effects Of Cadmium Stress On Key Enzyme Activities And Nutrient Accumulation And Yield Of Nitrogen Metabolism In Different Rice Varieties

Since the reform and opening, the social economy of our country has been rapidly developed. However, during the process of development, we have paid very heavy environmental price due to the lack of environmental awareness, among which soil heavy metal pollution is a very typical example. As one of the heavy metals which is harmful to the soil, Cadmium seriously affects agricultural production, and reports about Cadmium rice are rapidly seen. Cadmium pollution is not only directly harmful to the growth of rice, but also reduces its productivity and quality, moreover, it would jeopardize the health of people.In this paper, different varieties of rice are taken as the research object to discuss the difference of several nitrogen metabolism activity and NPK accumulation on plant according to Cadmium stress on different rice varieties through pot experiment. The results showed that:1.Compared with normol treatment, cadmium stress processing mainly for the inhibition of the activitiy of NR, cadmium stress promote the activitiy of GS,but depends on varieties,for example,to Yongyou 538,the increase of activitiy is obviously; The influence of cadmium stress on the activitiy of GOGAT shows that the promotion is nearly equal to the inhibition,based on the time,cadmium stress has promoted the activitiy of GOGAT in the period of nutrition growth,after the period of reproduction growth,it shows inhibition. Effects of cadmium stress on key enzymes of nitrogen metabolism of RiceVarieties are changed with the different genetype. Among the tested varieties,,Yongyou 538 is stronger than other four species in terms of the quality of Cadmium endurance, and it can be further studied as a Cadmium resistance variety in the aspect of Nitrogen metabolism.1. The biggest influence of Cadmium Stress on NPK nutrient content of rice lies in N, though it also affects the content of P2O5 and K2O, the effect is not so significant enough to be noticed. Studies have shown that Cadmium Stress is not conductive to the accumulation of nutrient in rice.2.For each period, the nutrient content of different varieties of different parts changed as different genotype.To the accumulation of nutrients, Full panicle stage under cdmium stress is conducive to the accumulation of japonica rice varieties to N.but do no good to indica rice varieties,the same as In the milk stage and yellow ripening period.Cadmium stress basic inhibition to the accumulation of rice P, although Yongyou 538 has some ups and down to the accumulation of P,but the difference is not obvious, it’s means that during whole growth period, the impact is not big amount of phosphorus accumulation in it,it shows good resistance to cadmium.The milk stage、ripe stage of rice on the impact on the K cumulants under cadmium stress changes with different genotype,and it’s not conducive to the accumulation of potassium in the rice yellow ripening period. Just in terms of total nutrient accumulative, promoting effect is obvious to the overall trend in the early,in the late especially the yellow ripening period, the inhibition enhance and do no good to the preduction.3.Cadmium Stress is not good for the accumulation or transportation of rice nutrient and DM, Different rice varieties’amount of DM accumulation of aboveground organs all lower than in normal processing of cadmium,and the difference reached significant level.According to the proportion of the DM from various organs,the DM’cumulantion changed with the different genetype,so are the stems and leaves of rice.Wther the DM is increased or creased,it’s doing no good for the nutriention’transportion to the seed. Under the influence of Cadmium Stress, though the DM accumulative ratio of Yongyou 538 declines, the difference is not obvious and its productivity increased by DM accumulation’s increase, which are all persuasive evidence to support that the quality of Cadmium endurance of Yongyou 538 is strong.4.Cadmium stress has made all the rice’s plant height、length of ear and the seed setting rate droped,but the difference is not remarkable,except the Huanghua zhan’s effective ear,others do not get reach to remarkable,among all the varieties,just Yongyou 538’s output increased(An increase of 38.7%),while Other varieties are decreased.5. Compared with normol treatment, the cadmium content in all varieties rice has increased.and the growth is very large,the largest is WUyun Jing 27,in the other order are Huanghua zhan、Shenliang you 5867、Yongyou 5550 and Yongyou 538, compared with the smallest noe-Yongyou 538, the first four varieties’s growth respectively are the latter’s 3.40 times、1.73 times、1.45 times and 1.37 times, all varieties ’difference of cadmium content in rice reached the significant level. Hybrid japonica rice is better than hybrid indica on the resistance to cadmium, conventional indica is better than conventional japonica rice, hybrid japonica rice is better than conventional japonica rice,,hybrid indica is better than conventional indica. On the varieties of it,Wuyun Jing 27 is the most sensitive to cadmium stress reaction,shows no resistance to cadmium,Huanghua Zhan second, Compared with the other four varieties,Yongyou 538 shows more able to adapt to cadmium stress.and it’s maybe related to the varieties’biomass and the difference of production.