稻米镉关键积累时期研究

The Key Period of Cadmium Accumulation in Rice

探明水稻不同生育期镉积累特征对于稻米安全生产具有重要的科学价值与现实意义,本研究采用水培试验方法,于水稻不同生育期分阶段添加外源镉,分析水稻不同生育期低浓度镉(50μg·L^(-1))胁迫下水稻每个生育期、主要部位镉含量及其内在关联。抽穗期阶段镉胁迫对水稻籽粒镉积累速率影响最为明显,最高达到3.41μg·蔸^(-1)·d^(-1)。孕穗期和抽穗期阶段镉胁迫对稻米镉积累量贡献率较高,中嘉早17号分别为40.51%、31.66%,湘晚籼13号分别为37.97%、35.46%。研究表明,孕穗期、抽穗期是控制镉米形成的关键时期,本结果可为镉超标稻田的安全生产及阻控米镉积累提供支持和科学指导。

It has important scientific value and practical significance to explore the characteristics of the cadmium accumulation in rice at different growth stages for safely producing rice. In this study, cadmium accumulation in rice at different growth periods, cadmium distribution in different parts of the rice and the intrinsic relationship between them were investigated by water culture experiment with low concentration of exogenous cadmium addition at different growth stages of rice. The cadmium could accumulate at a relatively high content at booting and heading stage of rice after exposure to exogenous cadmium indicating that the booting and heading stage were the key period of cadmium accumulation in rice. At the heading stage, the cadmium stress had the most significant effect on the cadmium accumulation rate of rice, reaching a maximum of 3.41 μg· clump-1· d-1. The contributions of cadmium stress to the cadmium accumulation in the booting and heading stage were higher. In those two stages, the contributions rate of the Zhong Jiazao 17 was 40.51%, 31.66% and the Xiang Wanxian 13 was 37.97%, 35.46% respectively. The study could provide valuable implications for control of cadmium pollution in rice field.