摘要： 探讨水果黄瓜幼苗对铅胁迫的响应机制,为揭示水果黄瓜抗铅性提供理论依据。在200 mg/L硝酸铅胁迫下,研究了不同浓度的(50,100,300,500 μmol/L)外源一氧化氮(Nitric oxide,NO)对水果黄瓜种子萌发以及幼苗可溶性蛋白含量、丙二醛(MDA)含量、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性、超氧化物歧化酶(SOD)活性及叶绿素相对含量的影响。结果表明,200 mg/L的硝酸铅对水果黄瓜种子的萌发起到显著的抑制作用,并使可溶性蛋白与丙二醛的含量升高,POD、CAT活性以及叶绿素相对含量显著降低;加入硝普钠(SNP,NO供体)对水果黄瓜种子的发芽率、发芽势及发芽指数有明显的促进作用,同时降低了丙二醛的含量,增加POD、CAT、SOD活性以及叶绿素相对含量和可溶性蛋白质含量。外源NO能显著促进Pb²⁺胁迫下水果黄瓜种子萌发,增强细胞的渗透调节能力,提高保护酶活性,明显缓解幼苗叶片受到的氧化损伤,其中以100 μmol/L SNP处理的效果最好。

关键词: 水果黄瓜, 一氧化氮, 铅胁迫, 种子萌发, 生理特性

Abstract: The mechanisms of Cucumis sativus L.seedlings responding to Pb stress were studied in order to provide a theoretical basis for lead-resistant.The effects on the germination of cucumber seeds and the contents of soluble protein and MDA,the activities of POD,CAT and SOD and chlorophyll relative contents of cucumber seedlings of the different concentration of exogenous NO(50,100,300,500 μmol/L)were studied under 200 mg/L Pb(NO₃)₂.The results showed that the germination of fruit cucumber seeds was inhibited significantly,the contents of soluble protein and MDA increased,while the activities of POD,CAT and chlorophyll relative contents decreased obviously under 200 mg/L Pb(NO₃)₂.The germination percentage,germination potential and germination indexes of fruit cucumber seeds were stimulated greatly with adding sodium nitroprusside (SNP,nitric oxide donor),which decreased the contents of MDA at the same time,while raised the activities of POD,CAT and the contents of relative chlorophyll and soluble protein.It could obviously promote the germination of fruit cucumber seeds under Pb²⁺ stress with adding exogenous nitric oxide,enhance the osmotic adjustment capacity of cell,increase the activity of protective enzyme and significantly alleviate oxidative damage to seeding leaves,the effect was the best when SNP was at 100 μmol/L especially.

Key words: Fruit cucumber, Nitric oxide, Pb²⁺ stress, Seed germination, Physiological characteristics

中图分类号: 

• S642.01