【摘要】 【目的】研究外源一氧化氮(NO)供体硝普钠(SNP)对铅(Pb)胁迫娃娃菜种子萌发及其幼苗生理特性的影响,为探索Pb毒害娃娃菜的缓解途径提供科学依据。【方法】分别对Pb胁迫[500.0 mg/L Pb(NO3)2]娃娃菜种子及其幼苗施加不同浓度(50.0、100.0、200.0、500.0和1000.0μmol/L)的SNP溶液,观察各处理种子萌发及其幼苗生长状况,测定分析幼苗的相对电导率(REC)和叶绿素、丙二醛(MDA)、脯氨酸(Pro)含量及超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性等指标。【结果】在Pb胁迫下,娃娃菜种子的发芽率、发芽势和发芽指数降低,幼苗鲜、干重和叶绿素含量减少,抗氧化酶活性升高,REC提高,MDA含量增加。适宜浓度的SNP处理能提高Pb胁迫娃娃菜种子的萌发效果;100.0μmol/L SNP可显著提高幼苗的CAT活性(P<0.05,下同),明显提高SOD活性,显著减缓叶片REC升高;200.0μmol/L SNP处理可显著增加Pb胁迫娃娃菜幼苗的叶绿素a(Chla)和叶绿素b(Chlb)含量,使根和芽的鲜、干重显著增加,显著减缓MDA含量增加;50.0μmol/L SNP处理能显著增强幼苗的SOD活性和促进Pro合成。【结论】低浓度(50.0～200.0μmol/L)外源SNP能通过增强娃娃菜的抗氧化酶活性和促进渗透调节物质生成以减轻膜脂过氧化作用,使娃娃菜的生理代谢趋于稳定,从而提高娃娃菜的耐Pb胁迫能力。更多还原

【Abstract】 【Objective】The effects of exogenous nitric oxide(NO)donor sodium nitroprusside(SNP)on seed germination and seedling physiological characters of Brassica pekinensis were studied under lead(Pb)stress to provide a scientific basis for exploring paths for alleviating Pb poisoning B. pekinensis.【Method】Different concentrations(50.0,100.0,200.0,500.0 and 1000.0 μmol/L)of SNP solutions were applied to the B. pekinensis seed and seedlings under Pb stress[500.0 mg/L Pb(NO3)2]. The seed germination and seedling growth were observed,and the relative conductivity(REC),chlorophyll content,malondialdehyde(MDA)content,proline(Pro)content,superoxide dismutase(SOD)activity and catalase(CAT)activity were determined and analyzed.【Result】Under the stress of Pb,the B. pekinensis seed germination rate,germinating energy and germination index,fresh and dry weight of seedling,chlorophyll content decreased,antioxidant enzyme activity increased,REC activity and MDA content increased. Proper concentrations of SNP could increase the effects of Pb stress on seed germination. 100.0 μmol/L SNP significantly increased the activity of CAT(P<0.05,the same below)of seedlings,and increased SOD activity,and significantly alleviated leaf REC increase. 200.0 μmol/L SNP could significantly increased the contents of chlorophyll a(Chla)and chlorophyll b(Chlb)in the B. pekinensis seedlings under Pb stress,and increased the fresh weight of roots and stems,significantly alleviated MDA content increase. 50.0μmol/L SNP could significantly enhance SOD activity and Pro synthesis in seedlings.【Conclusion】Low concentration(50.0-200.0 μmol/L)exogenous SNP can reduce membrane lipid peroxidation through increasing antioxidase activity and promoting osmotic adjustment substances hylogenesis of B. pekinensis. Then physiological metabolism of B. pekinensis is stable and its Pb resistance can be improved.更多还原