外源褪黑素对盐胁迫下老化燕麦种子萌发及幼苗的影响

以老化饲用燕麦种子为对象,探讨外源褪黑素对NaCl胁迫下老化燕麦种子萌发和幼苗相关形态和生理特性的影响。结果表明:在无胁迫时添加褪黑素可以提高老化燕麦种子的发芽率,并能增加幼苗游离脯氨酸和可溶性蛋白质含量且增强过氧化物酶活性,降低丙二醛含量;不同浓度的外源褪黑素(100μmol/L、300μmol/L、500μmol/L、800μmol/L、1000μmol/L)处理均能显著提高NaCl(浓度150mmol/L)胁迫下老化燕麦种子的发芽率、苗高、根长、苗鲜重、过氧化物酶活性、可溶性蛋白质和游离脯氨酸含量,显著降低幼苗根冠比和丙二醛含量(P<0.05)。加权隶属函数分析表明,提高老化燕麦种子NaCl胁迫下活力的最佳褪黑素浓度为500μmol/L,此时相对于NaCl胁迫,种子发芽率、苗鲜重、过氧化物酶活性和可溶性蛋白质含量分别提高了245.61%、325.55%、52.28%、121.27%。

Effects of Exogenous Melatonin on Seeds Germination and Seedling of Aged Oat under Salt Stress

In order to investigate the effects of exogenous melatonin on seed germination and seedling morphological and physiological characteristics of aged forage oat(Avena sativa)under salt stress,we set up the control group(distilled water,CK),the exogenous melatonin(MT)group(concentration of 100μmol/L,300μmol/L,500μmol/L,800μmol/L,and 1000μmol/L),the sodium chloride group(NaCl,concentration of 150mmol/L)and the mixed group of sodium chloride and MT of each concentration(NaCl+MT).The results showed that adding MT without salt stress could increase the germination rate of aging oat seeds,the content of osmotic regulator(free proline and soluble protein)and protective enzyme(peroxidase,POD)activity of seedlings,but reduce the of malondialdehyde(MDA)content.Treatment with different concentrations of exogenous MT significantly increased germination rate,seedling height,root length,seedling fresh weight,POD activity,soluble protein and free proline content of aged oat seeds under sodium chloride stress,and significantly reduced root to shoot ratio and MDA content of seedlings(P<0.05).The analysis of weighted subordinate function showed the optimal MT concentration to improve the vitality of aging oat seeds under salt stress was 500μmol/L,and the germination rate,seedling fresh weight,POD activity and soluble protein content of seeds were increased by 245.61%,325.55%,52.28%and 121.27%,respectively,compared with alone stress of sodium chloride.