蒭雷草对盐胁迫的生理响应

Physiological response of Thuarea involuta under salt stress

关键词:  蒭雷草, 盐胁迫, 丙二醛, 抗氧化酶, 渗透调节, 生理响应

Key words:  Thuarea involute, salt stress, MDA, antioxidase, osmotic regulator, physiological response

摘要:

该文选择从西沙东岛采集蒭雷草,通过分株繁殖挑选健壮植株作为材料,模拟热带珊瑚岛生境设置不同浓度NaCl处理,研究不同程度的盐胁迫对其植株叶片丙二醛(MDA)、抗氧化酶以及渗透调节物质的影响。结果表明:(1)短期(28 d)盐胁迫下,NaCl浓度的增加并未加速蒭雷草叶片细胞发生膜脂过氧化作用,MDA含量增加幅度较小; 随着盐胁迫时间延长及NaCl浓度增加,蒭雷草叶片细胞膜脂过氧化损伤的程度加深,MDA含量逐渐上升,最大值出现在400 mmol·L^-1。(2)短期(28 d)盐胁迫下,低浓度(200 mmol·L^-1)NaCl显著提高超氧化物歧化酶(SOD)活性,高浓度(400 mmol·L^-1)NaCl显著提高过氧化氢酶(CAT)活性; 而过氧化物酶(POD)活性随盐胁迫时间的延长及浓度的增加逐渐升高。(3)蒭雷草在盐胁迫环境下,机体组织不断积累可溶性蛋白(SP)和脯氨酸(PRO)含量以提高渗透调节能力,平衡细胞内外渗透势,从而达到缓解盐害的目的。整个盐胁迫过程中,蒭雷草机体组织将抗氧化酶防御系统和渗透调节机制相结合,减缓了细胞膜脂过氧化的损伤和细胞失水带来的生理干旱,表现出较强的耐盐能力。综上研究结果,为蒭雷草在南海诸岛人工群落构建、植被恢复中的应用以及营造良好生态环境提供了科学支撑。

Abstract:

In order to test the ability of Thuarea involuta to adapt to adversity and to reveal its mechanism of salt tolerance, we collected samples from the tropical coral Xisha Dongdao Island, and selected vigorous plants as the subsequent experiment materials through vegetative propagation, which were then treated with different salt stress degrees. We studied the effects of treatments with different NaCl concentrations on the contents of Malondialdehyde(MDA), antioxidase and osmotic regulator in leaves of T. involuta. The results were as follows:(1)The increase of NaCl concentration did not accelerate the membrane lipid peroxidation of T. involuta leaf cells under a short term of salt treatment(28 d), but the peroxidation effect worsened with the extension of salt treatment time and increase of NaCl concentration, which also, resluted in a gradually rising of the content of MDA, reaching the peak at 400 mmol·L^-1 of NaCl concentration.(2)Under the short term of salt stress treatment(28 d), the activities of SOD and CAT were significantly increased under the low(200 mmol·L^-1)and high(400 mmol·L^-1)NaCl concentrations, respectively, the activity of POD gradually ascended with the increase of salt stress time and NaCl concentration.(3)We discovered that under salt treatment, T. involuta accumulated SP and PRO to improve the osmotic regulation ability, which balanced the osmotic potential inside and outside the cell membranes and lowered the demage of salt stress. In conclusion, T. involuta can apply both of the antioxidant enzyme defense system and osmotic regulation mechanism under salt stress, to reduce the damage caused by lipid peroxidation of cell membrane and to ease physiological drought. In this case, we regarded the species has high salt tolerance. The results can provide scientific foundation for artificial community construction of T. involuta, vegetation restoration and landscaping design on South China Sea Islands, and it has great significance for sustainable development to tropical coral islands in China.