硒对镉毒害下白萝卜生理特性的影响

Effects of Selenium on Physiological Characteristics of Radish Under Cadmium Poisoning

以白萝卜为试材,采用土培盆栽试验法,研究了施加不同浓度外源硒(0.5 mg·kg^(-1)和1.0 mg·kg^(-1))对不同浓度镉(5 mg·kg^(-1)和30 mg·kg^(-1))胁迫下白萝卜光合色素含量及硒和镉吸收转运的影响,以期为外源硒缓解镉对植物毒害作用的最佳浓度提供参考依据。结果表明:与对照相比,单镉处理,随镉浓度的增加,叶绿素a和类胡萝卜素含量明显降低,白萝卜地上部和地下部镉含量显著增加,硒含量明显降低,使镉和硒的转运系数逐渐增加;单硒处理,随硒浓度的增加,叶绿素a和叶绿素b含量逐渐增加,但对类胡萝卜素含量的影响不显著,地上部和地下部镉含量逐渐降低,硒含量逐渐增加,使镉和硒的转运系数逐渐增加。硒镉交互作用与对照相比白萝卜叶绿素a和类胡萝卜素含量显著升高,地上部和地下部硒含量与对照相比均显著增加,硒镉交互作用下与对照相比白萝卜叶绿素a和类胡萝卜素含量显著升高,地上部和地下部硒含量均显著增加,施加0.5 mg·kg^(-1)外源硒与单镉处理相比镉含量和镉转运系数均增加;外源硒与5 mg·kg^(-1)镉交互作用使硒转运运数增加,与30 mg·kg^(-1)镉交互作用使硒转运系数显著降低。研究表明在试验浓度范围内2种硒浓度处理均对镉胁迫下的白萝卜有一定缓解效果,但0.5 mg·kg^(-1)硒对低浓度镉(5 mg·kg^(-1))胁迫下白萝卜毒害的缓解效果最好。

Taking radish as test material, the pot experiment were conducted to study the effects of exogenous selenium(0.5 mg·kg^(-1) and 1.0 mg·kg^(-1)) on photosynthetic pigment content and selenium and cadmium absorption and transport in radish under cadmium stress with different concentration(5 mg·kg^(-1) and 30 mg·kg^(-1)),in order to provide reference for the best concentration of exogenous selenium on alleviate toxic effect of cadmium(Cd) on plants.The results showed that with the increase of cadmium concentration, the contents of chlorophyll a and carotenoid decreased, the contents of cadmium significantly increased in aboveground and underground parts of radish, while the contents of selenium decreased, so that the transport coefficient of cadmium and selenium increased gradually.With the increase of selenium concentration, the contents of chlorophyll a and chlorophyll b gradually increased, but the effect on carotenoids was not significant.The cadmium content in aboveground and underground parts gradually decreased, while the selenium content gradually increased, so that the transport coefficient of cadmium and selenium gradually increased.Under selenium-cadmium interaction, the contents of chlorophyll a and carotenoid in radish significantly increased compared with the control, and the contents of selenium in aboveground and underground parts of radish significantly increased compared with the control, and the content of cadmium and the transfer coefficient of cadmium increased when 0.5 mg·kg^(-1) selenium was applied compared with the single cadmium treatment.The interaction between exogenous selenium and 5 mg·kg^(-1) cadmium increased the selenium transport coefficient, while the interaction between exogenous selenium and 30 mg·kg^(-1) cadmium significantly reduced the selenium transport coefficient.The results showed that the two selenium concentrations within the experimental concentration range had certain alleviating effect on radish under cadmium stress, but 0.5 mg·kg^(-1) selenium had the best alleviating effect on radish under cadmium stress(5 mg·kg^(-1)).