磷素对紫花苜蓿镉累积和抗氧化酶活性的影响

为研究磷素对紫花苜蓿镉累积和抗氧化酶活性的影响，以紫花苜蓿(中苜一号)为材料，采用土培试验，设置不同磷水平(0、40、80、160、240、300 mg·kg^-1)和镉含量(0、2、20 mg·kg^-1)，分析紫花苜蓿生物量、镉含量、镉亚细胞分布、丙二醛(MDA)含量和过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性。结果表明：在相同镉处理下，随施磷水平的增加，紫花苜蓿地上部、地下部镉含量最多降低了41.7%和39.2%；生物量、POD活性、SOD活性和CAT活性呈先增加后降低趋势。在相同施磷水平下，与未添加镉处理相比，低含量(2 mg·kg^-1)镉处理时，紫花苜蓿生物量最多增加了28.8%，高含量(20 mg·kg^-1)镉处理时，生物量最多降低了9%；随着镉处理含量的增加，紫花苜蓿MDA含量和CAT活性显著增加，POD和SOD活性先增加后降低。镉含量在各亚细胞组分中的次序为细胞壁>细胞质>线粒体>叶绿体，且均随施磷量的增加而显著降低，细胞壁镉含量占比最高达...

Effects of phosphorus on cadmium accumulation and antioxidant enzyme activities of alfalfa

To explore the effects of phosphorus application on cadmium accumulation and antioxidant enzyme activity of alfalfa, pot experiments were conducted to assess the effect of phosphorus on biomass, cadmium content, subcellular distribution, malondialdehyde (MDA)content, and the activities of peroxidase(POD), superoxide dismutase(SOD), and catalase(CAT)under cadmium stress. The results showed that alfalfa biomass and activities of POD, SOD, and CAT first increased and then decreased with increasing phosphorus application levels under the same cadmium treatment concentration. The content of cadmium in the shoots and roots decreased by 41.7% and 39.2% at most. Under the same phosphorus application level, the biomass of alfalfa increased by 28.8% at most in the 2 mg · kg^-1 cadmium treatment, whereas it was decreased by 9% at most in the 20 mg·kg^-1 cadmium treatment. MDA content and CAT activity were significantly increased, while POD and SOD activities increased first and then decreased with increasing cadmium treatment contents. The content of cadmium in subcellular fractions was in the following order:cell wall>cytoplasm>mitochondria>chloroplast, which decreased significantly with the increase of phosphorus application contents, the highest percentage of cadmium in cell wall was 64%. Taken together, the results indicate that the tolerance of alfalfa to cadmium is promoted, and the toxic effect of cadmium on alfalfa is alleviated through phosphorus application.