IAA改善PEG处理下白三叶幼苗叶片抗氧化保护和渗透调节能力  

Improvement of oxidation resistance and osmotic regulation of white clover seedlings by exogenous auxin under polyethylene glycol stress

作　　者：李亚萍[1] 彭燕[1] 

机构地区：[1]四川农业大学动物科技学院,四川成都611130

出　　处：《草业科学》2017年第11期2295-2302,共8页Pratacultural Science

基　　金：国家自然科学基金(31372371)

摘　　要：以‘Pixie’白三叶(Trifolium repens cv.‘Pixie’)为试材,通过PEG(聚乙二醇-6000)模拟干旱胁迫,研究植物生长素(IAA)对白三叶幼苗抗旱性的影响。结果表明,1μmol·L^(-1) IAA能够显著(P<0.05)提高15%PEG(-0.3 MPa)干旱胁迫下白三叶幼苗的抗旱性;外源IAA不同程度地提高了白三叶幼苗叶片超氧化物歧化酶、过氧化物酶、过氧化氢酶和抗坏血酸过氧化物酶活性,以及还原型ASA和GSH的含量,降低相对电导率、丙二醛、超氧阴离子和过氧化氢含量,有效缓解了叶片膜质损伤和氧胁迫伤害;外源IAA亦可显著提高白三叶叶片总氨基酸和游离脯氨酸含量,有效降低了渗透势,提高叶片相对含水量。相似地,干旱条件下外源1μmol·L^(-1) IAA提高了离体叶片相对含水量并有效缓解了膜质损伤,但60μmol·L^(-1)极性运输抑制剂(NPA)以及60μmol·L^(-1)合成抑制剂(L-AOPP)不同程度地加剧了叶片失水和膜质损伤。以上结果表明:1μmol·L^(-1)IAA通过提高干旱胁迫下白三叶抗氧化保护能力和渗透调节能力,改善了白三叶幼苗的抗旱性。This research was conducted to investigate the effect of auxin （IAA） on the drought tolerance of white clover （Trifolium repens cv. ‘Pixie’） under drought stress induced by polyethylene glycol 6000（PEG 6000） nutrient solution. The results showed that 1 μmol·L-1 IAA significantly improved the drought tolerance of white clover fed with a nutrient solution containing 15% PEG （-0.3 MPa）. Exogenous IAA improved the activities of antioxidant enzymes including superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase to varying degrees, increased the contents of ascorbate and glutathione, decreased electrolyte leakage, and decreased the contents of malondialdehyde, superoxide anions, and H2O2. These observations indicated that IAA effectively reduced oxidative damage and lipid modifications. Exogenous IAA also significantly increased the contents of total amino acids and proline, and efficiently decreased the osmotic potential, which was associated with an increased relative water content. Similarly, under drought conditions, the treatment with exogenous IAA （1 μmol·L-1） significantly improved the relative water content and alleviated lipid injury in detached leaves, but treatments with auxin biosynthesis inhibitors （60 μmol·L-1 naphthylphthalamic acid and 60 μmol·L-1 amino oxyphenylpropionic acid） decreased the relative water content and lipid injury in detached leaves. In conclusion, the results indicated that IAA can effectively increase the capacities of white clover for antioxidant protection and osmoregulation, thereby leading to an improved drought tolerance.

关 键 词：白三叶 干旱胁迫 生长素 膜质损伤 抗氧化保护 渗透调节 

分 类 号：S541.2[农业科学—作物学]