直立型扁蓿豆幼苗对不同盐胁迫的生理生化响应

Physiological and biochemical responses of Medicago ruthenicus(L.)Sojak cv.Zhilixing seedling to different salt stresses

选用盆栽法,以NaCl单盐、NaCl+Na 2SO 4复盐、Na 2CO 3+NaHCO 3复盐对直立型扁蓿豆幼苗进行盐胁迫处理,通过株高、叶绿素、丙二醛(MDA)、游离脯氨酸、超氧化物歧化酶(SOD)和过氧化物酶(POD)等含量的变化,探究其在不同盐胁迫下的生理生化响应。结果表明:直立型扁蓿豆在100~200mmol/L盐胁迫时生长受到抑制,其中Na 2CO 3+NaHCO 3复盐胁迫受到的抑制程度最大,生长速率均在0.29cm/d以下。随着盐浓度的增大,丙二醛和游离脯氨酸的含量显著增加,当盐浓度小于等于150mmol/L时,其幼苗叶片通过自身的渗透调节和抗氧化酶系统的调控均可以继续生长,具一定的耐盐性;通过成苗率发现,其半致死浓度为200 mmol/L,此时幼苗在Na 2CO 3+NaHCO 3复盐胁迫下抗氧化酶系统受到严重伤害,超过其耐受限度,导致POD酶活性显著下降,并且CO32-和HCO 3-积累所带来的毒害作用要大于Cl-和SO 42-。

NaCl,NaCl+Na 2SO 4 and Na 2CO 3+NaHCO 3 were used to treat the seedling under the salt stress.To explore the physiological and biochemical responses to the seedlings under the different salt stresses with the changes of plant height,chlorophyll,malondialdehyde,free proline,SOD and POD.Results showed that the vertical pamiricus in three kinds of salt stresses that 100-200mmol/L growth are suppressed,which restrained most complex in the Na 2CO 3+NaHCO 3.The growth rates were all below 0.29cm/d with the increase of salt concentration of malondialdehyde and free proline content increased significantly,as the salt concentration less than or equal to 150 mmol/L,it’s leaf could continue to grow through its osmotic adjustment and regulation of antioxidant enzyme system,which was particularly salt resistance.According to the seedling formation rate,its semi-lethal concentration was 200 mmol/L,the antioxidant enzyme system of the seedlings was seriously damaged under Na 2CO 3+NaHCO 3 compound salt stress,which exceeded its tolerance limit,leading to a significant decline in POD enzyme activity.In addition,the toxic effect brought by the accumulation of CO 32-and HCO 3-was greater than Cl-and SO 42-.