镉胁迫对草莓氮代谢及果实品质的影响

采用土壤盆栽试验,以丰香草莓品种为材料,研究镉胁迫对草莓氮代谢及果实品质的影响.结果显示,镉降低了草莓叶和根中的含氮量及叶中水解氨基酸总量,但各种水解氨基酸的变化趋势有一定的差异.镉胁迫下,草莓根中的游离脯氨酸含量和叶可溶性蛋白含量随镉处理浓度增加而增加.镉抑制草莓叶硝酸还原酶的活性,而使草莓叶中核糖核酸酶的活性升高.镉处理使草莓果实中的某些矿质元素及维生素C含量降低.更重要的是,镉被草莓吸收后,会积累在草莓果实中.草莓果实中镉的含量与土壤中镉的浓度的相关达极显著水平.在本实验条件下,当土壤中镉浓度超过0.267 mg/kg时,草莓果实的镉含量就将超过国家食品卫生标准,表明土壤中添加镉对草莓果实的品质也有影响.

Effect of Cadmium Stress on Nitrogen Metabolism and Fruit Quality of Strawberry

Pot experiments were conducted to investigate the effect of cadmium(Cd) stress on nitrogen metabolism and fruit quality of strawberry, and the strawberry cultivar 'Fengxiang' was used as the material. The results showed that Cd reduced the nitrogen content in leaves and roots of the strawberry and the total content of hydrolytic amino acids in the leaves, and that each hydrolytic ammo acid tended to vary in various degrees. Under Cd stress, free proline content and soluble protein content in strawberry rose with the Cd concentration. The Cd inhibited the activity of nitrate reductase in strawberry leaves, but increased the activity of ribonuclease. The Cd reduced the contents of mineral elements and vitamin C in strawberry fruit. Moreover, Cd was accumulated in a large number in the fruit after absorbed by strawberry. The Cd content in fruit showed highly significant correlation with the concentrations of Cd in soil. The Cd content in the fruit produced under this experiment exceeded the food safety standards when the Cd concentration in the soil was over 0.267 mg/kg. This suggested that addition of the Cd in the soil could also give impact to the fruit quality of strawberry.