硒对镉胁迫下菠菜生理特性、元素含量及镉吸收转运的影响

为了探讨硒(Se)对菠菜中的镉(Cd)胁迫造成毒害的缓解作用,采用盆栽试验,研究了不同浓度Se(0、0.5、2.0、4.0 mg·L-1)对不同浓度Cd(0.5和2.0 mg·kg-1)胁迫下菠菜生理特性、元素含量及Cd吸收转运的影响.结果表明:不同浓度的Se可使丙二醛(MDA)积累量显著降低,最佳作用下分别为两种浓度Cd单一胁迫下的53.93%和41.79%;不同浓度的Se可以缓解Cd胁迫对菠菜地上部和根部的抑制作用,最佳缓解条件下,菠菜地上部和根部的鲜重分别为两种浓度Cd单一胁迫时的1.13倍、1.29倍和1.31倍、1.37倍,干重分别为1.78倍、2.09倍和3.03倍、4.36倍;叶绿素含量显著提高,在最佳缓解浓度下分别是两种浓度Cd单一胁迫时的1.51倍和1.35倍;与两种浓度Cd单一胁迫相比,最佳缓解浓度下超氧化物歧化酶(SOD)活性分别提高了36.0%和42.8%;外源Se可以使地上部和根部的K、Na、Ca和Mg等元素的含量不同程度的增加;施Se可以有效的抑制菠菜根部对Cd的吸收、富集和向地上部的转运,使菠菜地上部和根部Cd含量显著降低,分别为两种浓度Cd单一胁迫下的65.77%、75.92%和46.11%、70.01%,表明外源Se能有效的减轻Cd胁迫对菠菜的毒害作用.对本研究所用的两种浓度Cd来说,最佳的缓解浓度为2.0 mg·L-1和4.0 mg·L-1.

Effects of selenium (Se) on the physiological characteristics, element contents, uptake and transportation of Cd in spinach under Cd stress

Pot experiments were performed to investigate the physiological mechanisms of selenium (Se) mitigation of Cadmium (Cd) toxicity in spinach. The effects of different concentration selenium (Se) (0, 0.5, 2.0 and 4.0 mg·L^-1) on the physiological characteristics, element contents and uptake and transportation of Cd in spinach under different concentrations of Cd (0.5 and 2.0 mg·kg^-1) stress were studied. The results showed that different concentrations of Se dramatically depressed malondialdehyde (MDA) accumulation. With the optimal Se concentration, the contents of MDA were 53.93% and 41.79% of those under single stress of Cd in two concentrations. Different concentrations of Se alleviated the inhibitory effects of Cd on the shoots and roots of spinach, and the fresh weight and dry mass of hoots and roots were 1.13, 1.29, 1.31, 1.37 and 1.78, 2.09, 3.03, 4.36 times those under single stress of Cd in two concentrations, respectively, with the optimal Se concentrations. Exogenous Se markedly increased the chlorophyll content, the content of chlorophyll was 1.51 and 1.35 times that under single stress of Cd in two concentrations, respectively, when the exogenous Se concentration were optimal. The superoxide dismutase (SOD) activities increased about 36.0% and 42.8%, respectively, compared with the single stress of Cd in two concentrations. Exogenous Se increased K, Na, Ca and Mg contents in the shoots and roots by different degrees. Under the application of Se, the uptake, bioaccumulation and translocation of Cd were effectively inhibited, and the Cd concentration in shoots and roots significantly decreased to 65.77%, 75.92% and 46.11%, 70.01% of those under single stress of Cd in two concentrations. Results indicated that Se application could effectively alleviate Cd-induced toxicity in spinach. The optimal Se concentration was 2.0 mg·L^-1 and 4.0 mg·L^-1.