摘要： 为了探究在UV-B辐射增强胁迫下，大豆根系活性氧代谢规律及其对抗氧化系统的响应，通过自然状态和增强UV-B辐射对比，对不同生育时期大豆根系的膜脂过氧化作用（丙二醛含量、相对电导率）、活性氧代谢（超氧阴离子产生速率、过氧化氢含量）、保护酶活性（超氧化物歧化酶活性、过氧化物酶活性、过氧化氢酶活性）、保护性物质含量（抗坏血酸含量、类胡萝卜素含量、脯氨酸含量）等一系列指标进行测定。结果表明，同对照相比，UV-B胁迫引起O₂^·和H₂O₂的积累，具体表现为：在开花期，UV处理与CK相比，O₂^·产生速率降低11.5%，H₂O₂含量升高9.9%，其余生育时期UV处理均高于CK，所有生育时期，UV处理与CK相比差异显著。导致MDA含量和相对电导率增大，具体表现为：MDA含量和相对电导率在所有生育时期，UV处理均高于CK，且差异显著。同时还可引起SOD、POD和CAT等保护酶活性降低，具体表现为：与CK相比，在分枝期，UV处理SOD升高15.5%、POD下降15.3%、CAT活性下降12.8%，其余生育时期均降低。除CAT活性在分枝期差异不显著外，所有生育时期，UV处理与CK相比均差异显著。AsA、Car和脯氨酸等保护性物质含量下降，具体表现为：与CK相比，在分枝期，UV处理AsA含量降低11.4%、Car降低15.4%、脯氨酸含量升高10.5%；在开花期，UV处理AsA升高31.2%、Car降低17.9%、脯氨酸含量升高20.7%，其余生育时期均降低。除Car含量在结荚期和脯氨酸含量在分枝期差异不显著外，所有生育时期，UV处理与CK相比均差异显著。因此，UV-B辐射增强可以使大豆根系活性氧代谢和膜脂过氧化程度加剧，细胞膜透性增大，并对其抗氧化系统产生损害，且随着大豆生育时期的延长，这种效应越为明显。

关键词: 植物生理生态, 逆境损伤, 对比试验, UV-B增强, 大豆根系, 活性氧, 抗氧化系统

Abstract: In order to explore the regulation of active oxygen metabolism and the response of antioxidant system in soybean root under enhanced UV-B radiation. Contrast with enhanced UV-B radiation through natural state,those was tested that the soybean roots' lipid peroxidation (malondialdehyde content and relative electrolytic conductivity),reactive oxygen species metabolism (super oxygen anion production rate and Hydrogen peroxide content),protective enzyme activity (superoxide dismutase activity,peroxidase activity and catalase activity) and protective substance content (ascorbic acid content,carotenoid content and proline content) of different growth stages of the soybean,and a series of different indexes were measured. The results showed that:compared with the control,enhanced UV-B radiation could cause O₂^· and Hydrogen peroxide accumulate. For specific performance,compared with CK,O₂^· producing rate and Hydrogen peroxide accumulating went down 11.5%,and went up 9.9% in florescence. The UV treatment was higher than CK in other reproductive period. Compared with CK,UV treatment was significantly different in all growth stages. And could lead MDA content and relative electrolytic conductivity to increasing. For specific performance,compared with CK,UV treatment was higher and significantly different in all growth stages for MDA content and relative electrolytic conductivity. And enhanced UV-B radiation conditions also could lead to protective enzyme activity reducing,such as SOD,POD and CAT. For specific performance,compared with CK,SOD,POD and CAT activity went up 15.5%,went down 15.3% and 12.8% for UV treatment in branch stage, other stages were lower. Compared with CK,UV treatment was significantly different except CAT activity in branch stage. Cause protective substances' content to decline,such as AsA,Car and Proline. For specific performance,compared with CK,AsA,Car and Proline content went down 11.4% and 15.4%,went up 10.5% for UV treatment in branch stage. And went up 31.2%,went down 17.9%,went up 20.7% in florescence. Other stages were lower. Compared with CK,UV treatment was significantly different except Car content in podding stage or proline content in branch stage. Therefore,enhanced UV-B radiation could cause the active oxygen metabolism and lipid peroxidation to speed up,membrane permeability to increase,and cause the antioxidant system to damage. And with the soybean growth period goes on,the effect moves obviously.

Key words: Plant physiological and ecology, Adversity damage, Contrast test, Enhanced UV-B radiation, Soybean's root, ROS, Antioxidative system

中图分类号: 

• S565.01