不同氮素水平对菜用甘薯叶片生理特性的影响

Effects of Different Nitrogen Levels on Physiological Characteristics of Vegetable Sweet Potato

以‘福薯18’为材料,研究不同氮肥用量对菜用甘薯生理代谢的影响。试验结果表明:氮不足或氮过量的情况下,‘福薯18’叶片游离脯氨酸含量增加、可溶性蛋白质含量下降。适量氮素水平下,由于‘福薯18’叶片SOD与POD活性随施氮量增加而增强,O2产生速率与相对质膜透性均减小。施氮量超过一定范围后,随施氮量的·增加SOD活性降低,虽然POD活性增强但其活性提高不能及时清除SOD催化产生的H2O2,O2的积累提高生物膜的过氧化·作用,导致质膜相对透性增加、离子大量外渗、相对电导率增加,这些均导致细胞受到伤害。

The active oxygen metabolism of vegetable sweet potato under different nitrogen levels were studied.The results show that the leaves of＂Fushu18＂had high free proline concentration and low soluble protein concentration under deficient or excessive N application.The activity of SOD and POD increased with nitrogen levels increasing under the suitable amount of nitrogen,leading to the decrease of production rate of O2 and permeability of membrane plasma.With nitrogen levels increasing,SOD activity decreased and POD activity increased when nitrogen level exceeded a certain amount,but increased POD couldn＇t clear H2O2 in time.At the same time,the accumulation of aggravated peroxidation of biomembrane leads to the increase of membrane permeability and extravasation of ion and the increase of relative conductivity.