Effect Of Cd Stress On Endogenous Polyamine And Its Anabolic In The Roots Of The Hybrid Rice And Their Parent

With the development of industrial and agricultural production and urbanization, the accumulation of cadmium in the soil, causing serious pollution of paddy, the excessive cadmium rice is a threat to animal and human health through the food chain. Rice is the main food crop in our country, at present, there are some studies of the different rice varieties resistant to heavy metal stress, but the hybrid rice combination of parent materials and different parent materials is less reported. Therefore, this study of Cd stress on the Cd concentration and polyamine anabolic effect of three hybrid rice and the parents root is to provide the evidence for looking for good parents. The results were as follows:(1) Under Cd stress,Cd accumulation in rice roots with the increase of Cd treatment concentration gradually increased, the Cd concentration of different varieties and materials was different. Maintainer D83B and restorer R498materials under high concentration of cadmium handling, cadmium content of them was close to2.5mg/kg, were both high absorbent materials, hybrid rice D83A cadmium concentration in medium to high concentration treatment was significantly higher than the other two hybrids. In each of concentration of cadmium treatment, cadmium concentration in the maintainer Chuannong1A and restorer SH527roots was lower, to show Chuannong1A and SH527material as low cadmium absorption materials and the advantages of good parents. The hybrids Chuannongyou527inherited two parental characteristics of the low cadmium absorption characteristics under different concentration of cadmium treatment, the minimum amplitude and the lowest cadmium content in roots.(2) As the different maintainer and restorer and three combination configuration hybrid rice combinations roots were subjected to different concentrations Cd treatment, Arg content and ADC activity mixed reactions. Overall, rice roots accumulated more Arg under cadmium stress, ADC activity was also increased with the increase of cadmium concentration. Maintainer D83B and restorer R498respectively most affected by Cd treatment, Arg content and ADC activity was significantly higher than other varieties, which was higher in hybrids D83A. This difference was particularly evident when treated with high concentration, in three variety of materials, Arg content all reached around 20mg/g, ADC activity was higher than100mol (Agm)·g-1·h-1. Arg content and ADC activity was the lowest in Chuannong1A and SH527compared with other materials, and the hybrid maternal Chuannongyou527inheritance of good genes, which showed relatively stable upward trend.(3)Rice parents under different Cd concentration treatment, polyamine content and (fSpd+fSpm)/fPut ratio in the roots were affected by varying degrees, the Put content with increasing concentrations of Cd showed a gradual upward trend, this trend of high absorption cadmium materials was particularly evident, under HCd processing, Put content in maintainer D83B, restorers R498, hybrids D83A was as high as90mol/gFW more. Spm, Spd and (fSpd+fSpm)/fPut ratio was decreased as the increase of Cd stress concentration, but Spm, Spd level and (fSpd+fSpm)/fPut ratio of low cadmium absorption rice such as materials Chuannong1A, SH527and its hybrids Chuannongyou527decreased less, showed a more stable trend. Meanwhile Put content of the high cadmium was larger relationship with cadmium uptake in stress cadmium, correlation coefficient of which in D83B was be of0.996. Correlation of Spd and Spm with cadmium uptake in low cadmium absorption materials was high, which of Spd with cadmium uptake was an R2of1.000in Chuannong1A.(4) Polyamines and Arg content and ADC activity was closely related with absorption capability of cadmium in rice materials roots. Cadmium uptake and polyamine and Arg content and ADC activity of the hybrids depended mainly on the corresponding parents, restorer parent had a greater influence on the offspring cadmium and the related indicators. There were two main reasons for different polyamine content in the higher and lower Cd uptake materials:First, Cadmium caused a massive accumulation of Arg, simultaneously activated the transformation pathway of Arg to polyamine, rather than low suction type rice, activation effect was more apparent in high absorption type rice, ADC activity was higher, Arg to Put was into relatively faster speed. Second, high concentrations of cadmium hindered the process of transformation Put to Spm and Spd, which resulted in excessive Put accumulation and caused further toxicity in high suction-type rice.