亚精胺对渗透胁迫下玉米幼苗叶片抗氧化非酶物质的影响

Effects of Spermidine on Antioxidation Non-enzyme Substance Contents in Leaves of Maize Seedlings under Osmotic Stress

研究了渗透胁迫下玉米品种农大108(抗旱性较强)和掖单13(抗旱性较弱)幼苗叶片中亚精胺(Spd)和抗氧化非酶物质含量的变化。结果表明,渗透胁迫2d,抗旱性弱的掖单13玉米幼苗叶片的过氧化氢(H2O2)和丙二醛(MDA)含量的上升幅度明显大于抗旱性强的农大108,而农大108幼苗叶片Spd、抗坏血酸(ASA)和谷胱甘肽(GSH)含量的上升幅度明显大于掖单13。胁迫条件下,外源Spd处理掖单13,不仅明显提高其幼苗叶片的Spd含量,而且ASA和GSH含量也明显提高,而其H2O2和MDA则明显下降;Spd的生物合成专一性抑制剂——甲基乙二醛-双(鸟嘌呤腙,MGBG)处理农大108,则明显抑制其在渗透胁迫下叶片中的Spd,ASA和GSH含量的上升,而明显促进其H2O2和MDA含量的上升。这些结果表明,渗透胁迫下玉米幼苗叶片中的Spd减轻活性氧对幼苗伤害的原因之一,可能是通过提高ASA和GSH等抗氧化非酶物质含量而降低活性氧水平。

The changes in contents of spermidine （Spd） and antioxidation non-enzyme substances were investigated in seedling leaves of two maize （Zea rnays L. ） cultivars,Nongda 108 （droughttolerant） and Yedan 13 （drought-sensitive） under osmotic stress. On the 2th day, after polyethylene glycol （PEG）-6000 treatment, MDA and H2O2 contents increased more significantly in leaves of Yedan 13 than in Nongda 108, while Nongda 108 showed a more significant increase in contents of Spd,ASA and GSH. The contents of Spd, ASA and GSH in seedling leaves of Yedan 13 after exogenous Spd treatment increased while the contents of MDA and H2O2 decreased. Exogenous methylglyoxal-bis （MGBG）,which is an inhibitor of Spd biosynthesis,resulted in the reduction of Spd,ASA and GSH contents and the increase of MDA and H2O2 contents in seedling leaves of Nongda 108 subjected to osmotic stress. The results suggested that osmoinduced Spd increment alleviate the osmoinduced reactive GSH contents and reducing MDA and H2O2 oxygen injury to seedlings via increasing ASA and contents in the leaves.