【摘要】 为开发更多的耐盐(海水)蔬菜新品种,本研究以兼具食用和药用价值的野生蔬菜蒲公英为材料,以200 mmol/L NaCl为单盐胁迫处理,以等Na~+含量的海水(盐浓度16 g/L)为复合盐胁迫处理,研究不同时间(0、3、6 h和12 h)盐胁迫下超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性,膜脂过氧化产物丙二醛(MDA)含量及渗透调节物质可溶性蛋白含量的变化。结果表明:与0 h相比,盐胁迫处理3 h和6 h时,蒲公英叶片中的三种抗氧化酶(SOD、POD和CAT)活性、MDA及可溶性蛋白含量迅速增加(P <0. 05),12 h时三种酶活性与盐胁迫3 h或6 h相比有所降低,但仍显著高于0 h时;海水复合盐胁迫下蒲公英叶片SOD、POD和CAT活性的增加及MDA和渗透调节物质的积累,相较于NaCl单盐胁迫有所提高,但多数差异不显著(P>0. 05)。综上所述,受到盐胁迫时,蒲公英快速启动细胞内的保护酶系统,细胞膜透性和可溶性蛋白含量增加,使细胞维持较低的渗透势,以抵抗逆境胁迫,但植株受到较高浓度盐胁迫一段时间后,体内积累了大量活性氧,其活性氧清除酶活性降低,植株生长受到显著抑制。更多还原

【Abstract】 In order to develop more new species of salt(seawater) tolerant vegetables,the wild dandelion with both edible and medicinal values was used as the experimental material. Two treatments were set as single salt stress(200 mmol/L NaCl) and compound salt stress(seawater with 16 g/L of salinity with equal Na+concentration. The activities of superoxide dismutase(SOD),peroxidase(POD) and catalase(CAT),and the contents of malondialdehyde(MDA) and soluble protein under salt stress were determined after treated for 3,6 and 12 hours respectively. The results showed that the activities of SOD,POD and CAT and the contents of MDA and soluble protein increased rapidly under salt stress after 3 hours and 6 hours compared with no stress. Nevertheless,the activity of the three antioxidant enzymes decreased after 12 hours compared with that after 3 hours and 6 hours under salt stress,but they were still higher than that of no stress. The compound salt(seawater) stress increased the activity of antioxidant enzymes and the accumulation of MDA and soluble protein compared with single salt(NaCl) stress,but most differences were not significant. In summary,when subjected to salt stress,the protective enzyme system in dandelion was rapidly activated,and the cell membrane permeability and soluble protein content increased,in order to maintain lower osmotic potential of cells to resist salt stress. However,a large amount of reactive oxygen species could accumulated in the plants after a period of high concentration salt stress,and the activity of reactive oxygen scavenging enzymes decreased,so the plant growth was significantly inhibited.更多还原