外源亚精胺对盐胁迫下燕麦幼苗生长及生理特性的影响

Effects of Exogenous Spermidine on the Growth and Physiological Characteristics in Oat Seedlings under Salt Stress

为探讨外源喷施亚精胺(Spd)对燕麦幼苗生长和耐盐性的影响,该研究选用燕麦品种‘白燕5号’为试验材料,通过水培试验研究70 mmol/L盐胁迫下(NaCl和Na2SO4摩尔比1∶1混合),叶面喷施不同浓度的亚精胺对燕麦幼苗生长、根系活力、抗氧化酶活性以及丙二醛、游离脯氨酸和离子含量的影响。结果显示:(1)盐胁迫显著抑制了燕麦幼苗生长,喷施0.75 mmol/L Spd使盐胁迫下幼苗地上、地下干重和根系活力分别显著提高34.1%、23.8%和24.7%。(2)喷施0.75 mmol/L Spd使幼苗叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性较对照分别显著增加了17.0%、22.9%和23.7%,根系中分别显著增加了43.0%、19.4%和91.2%,并使幼苗叶片和根系中的MDA含量分别显著降低了25.2%和12.8%。(3)喷施0.75 mmol/L Spd使燕麦幼苗叶片和根系游离脯氨酸(Pro)含量分别显著增加了63.3%和362.6%,并使叶片Na^(+)/K^(+)、Na^(+)/Ca^(2+)和Na^(+)/Mg^(2+)值分别降低了6.7%、16.3%和4.9%。研究表明,在盐胁迫环境下,叶面喷施适宜浓度(0.75 mmol/L)Spd可通过提高燕麦幼苗抗氧化和渗透调节能力,维持生物膜系统的稳定,有效减轻渗透胁迫和离子毒害对幼苗的伤害,从而增强其耐盐性,促进幼苗生长。

In order to explore the effects of spermidine(Spd)on the growth and salt tolerance of oat seedlings,under 70 mmol/L salt(NaCl and Na2SO4 molar ratio 1∶1 mixed)stress,we used the salt-sensitive variety‘Baiyan5’as the test material with hydroponics methods.In the present study,we investigated the effects of different concentrations of spraying spermidine solution on oat seeding growth,root activity,antioxidant enzyme activity,malondialdehyde,free proline and ion accumulation.The results showed that:(1)salt stress significantly inhibited the growth of oat seedlings.Compared with spraying distilled water under salt stress,spraying 0.75 mmol/L Spd significantly increased the aboveground dry weight,underground dry weight and root activity of seedlings by 34.1%,23.8%and 24.7%,respectively.(2)The activities of superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT)increased by 17.0%,22.9%and 23.7%in leaves and increased 43.0%,19.4%and 91.2%in roots,respectively.MDA production in leaves and roots was inhibited by 25.2%and 12.8%,respectively.(3)It promoted the accumulation of free proline(Pro)in leaves and roots by 63.3%and 362.6%,respectively,and reduced the values of Na^(+)/K^(+),Na^(+)/Ca^(2+)and Na^(+)/Mg^(2+)in leaves by 6.7%,16.3%and 4.9%,respectively.our results indicate that foliar spraying of 0.75 mmol/L Spd can improve seedling antioxidant and osmotic adjustment ability under salt stress conditions,through maintaining the stability of the membrane system,reducing the damage of osmotic stress and ion poisoning to the seedlings,and enhancing the overall tolerant ability of the plants to salt stress.