| In this paper,nine early rice varieties widely planted in Hunan Province were selected as experimental materials,and four soils with different levels of cadmium(Cd)pollution in Beishan Town,Changsha County,Hunan Province were used as potting conditions,the effect of interaction between cultivars and soil on Cd content and environmental stability of rice were analyzed by AMMI model.Two rice varieties with large difference in Cd content were screened to carry out hydroponic test at seedling stage and soil pot experiment in whole growth period respectively.The Cd enrichment dynamics and migration,accumulation and distribution of Cd in rice under short-term and long-term Cd stress were studied in order to explore the important growth period and possible mechanism of Cd transportation and accumulation difference in rice and provide a theoretical reference for rice Cd reduction in Cd contaminated soil.The results are as follows:1.Lu Liangyou 996 had negative interaction with S1,S3 and S4 pilot soil,and the larger Di value of Lu Liangyou 996 indicated poor stability,but the average Cd content was 0.22 mg/kg,which exceeded the national standard(0.2 mg/kg)and was significantly higher than the other 8 test varieties,while Xiang Zao indica 32 had positive interaction with S1,S3 and S4 soil.The Di value was relatively good,and the average Cd content was 0.08 mg/kg,which was significantly lower than that of the other 8 rice varieties.Therefore,Lu Liangyou 996 and Xiangzao indica 32 were selected as Cd high accumulation and Cd low accumulation rice varieties.2.There was a significant or very significant positive correlation between the amount of Cd adsorbed on root surface and the Cd content in all parts of rice.When the concentration was low,it is easier for Xiang Zao indica 32 to absorb and accumulated Cd from the environment,but when the concentration of Cd was high,the Cd enrichment ability and Cd transfer ability of Lu Liangyou 996 root were stronger than that of Xiang Zao indica.In the early stage of Cd stress(0h~1d),Xiang Zao indica 32 had a faster stress response to the environment than Lu Liangyou 996,and the amount of Cd absorption and transfer to the upper part were relatively higher.But in the late stage of Cd stress(2d~8d),Luliangyou 996 had stronger Cd absorption capacity and Cd transfer ability.The results showed that the difference of Cd accumulation between two rice varieties was influenced by two factors,namely,the absorption of Cd from the root system and the transfer of Cd from root to shoot.3.the Cd distribution of rice root is relatively more during tillering stage ~ booting stage,and the accumulation of Cd in the upper part of rice is relatively more during grain filling stage ~ maturation stage.Compared with other growth period,the difference of Cd accumulation rate in aerial part and xylem during grain filling stage had great influence on Cd accumulation and distribution in rice.With the increase of Cd concentration in the environment,the concentration of sulfhydryl compounds in different vegetative organs of rice varied.4.The correlation results showed that the Cd content of stem had greater influence on Cd content of xylem,while Cd content of leaves was more closely related to Cd content of spike.the content of Cd in stem and leaf of rice was more closely related to PCs concentration.In addition,there was a close relationship between Cd content of spike and PCs concentration at the filling stage,while there was not strong correlation with the stems.Therefore,it can be concluded that there was a close relationship between PCs concentration and Cd accumulation in rice shoots,and the PCs concentration of root and leaf at the filling stage had great influence on Cd accumulation in the upper part of rice. |
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