[目的]探索一氧化氮(nitric oxide,NO)在八宝景天耐盐性产生中的作用.[方法]以八宝景天(Hylotelephium erythrostictum (Miq.) H.Ohba)水培苗为试材,经不同浓度NaCl、NaCl+硝普钠(SNP,NO供体)、NaCl+钨酸钠(T,硝酸还原酶活性抑制剂)及NaCl+ N'-硝基-L-精氨酸甲酯(L-NAME,一氧化氮合酶活性抑制剂)处理后,检测叶片的生理指标.[结果]盐胁迫下八宝景天叶片的相对电导率(REC)、丙二醛(MDA)和可溶性糖含量升高.SNP显著降低盐胁迫下八宝景天叶片的相对电导率和丙二醛含量,并增加可溶性糖含量,提高PSⅡ最大光化学效率(Fv/Fm)、PSⅡ实际量子产量(Y(Ⅱ))和光化学淬灭系数(qP),降低初始荧光(Fo)和非光化学淬灭系数(NPQ).NO抑制剂的施用则导致相反的结果,加剧盐胁迫对八宝景天的损伤.[结论]NO通过降低盐胁迫对膜系统的损伤,维持PSⅡ反应中心的活性,进而提高八宝景天的耐盐性.%This study aimed to explore the role of nitric oxide (NO) in the salt tolerance of Hylotelephium erythrostictum (Miq.) H.Ohba.The hydroponic cutting seedlings were treated with different concentrations of NaCl,NaCl+sodium nitroprusside (SNP,NO donor),NaCl+sodium tungstate (T,nitrate reductase inhibitor) and NaCl+N'-nitro-L-arginine-methylesterhydrochloride(L-NAME,nitric oxide synthase inhibitor),the physiological indexes of leaves were measured.The results showed NaCl treatment led to significant increases in the relative electric conductivity (REC),malondialdehyde (MDA)content and soluble sugar content.SNP significantly reduced the REC and MDA content and increased the soluble sugar content under salt stress.Moreover,SNP treatment resulted in the increases of photochemical efficiency of photosystem Ⅱ (Fv/Fm),photochemical yield (Y(Ⅱ)) and photochemical quenching coefficient (qP),and the decreases of minimal fluorescence (Fo) and non-photochemical quenching coefficient (NPQ).The application of NO inhibitor led to the opposite results,and exacerbated the injury of salt stress on H.erythrostictum.These results indicated that NO could maintain the activity of PS Ⅱ reaction center,and reduce the damage of membrane system by salt stress to enhance the salt tolerance of H.erythrostictum.
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