H_(2)S对盐胁迫下黄瓜幼苗生长生理的影响

Effect of H_(2)S on growth physiology of cucumber seedlings under salt stress

【目的】研究H_(2)S对盐胁迫下黄瓜幼苗生长抑制的缓解作用,为黄瓜耐盐栽培提供一定的科学依据。【方法】选用黄瓜品种新春四号为研究材料,采用气候箱内水培法,NaCl(50 mmol/L)胁迫下叶面喷施H_(2)S供体NaHS(200μmol/L)和H_(2)S合成抑制剂PAG(DL-炔丙基甘氨酸,150μmol/L)。【结果】与NaCl胁迫相比,NaHS叶面喷施可改善黄瓜幼苗生长状况,地上、地下干质量增加29.12%和48.52%。叶片可溶性糖、脯氨酸含量增加53.99%和22.21%,光合色素含量与叶绿素荧光参数Fv/Fm显著升高,同时,过氧化氢(H2O2)和丙二醛(MDA)含量降低37.79%和24.27%,抗氧化酶活性同样降低,而PAG处理的黄瓜幼苗则相反。【结论】H_(2)S可以通过增加渗透调节物质的积累,降低光合色素的减少,维持PSII最大光化学效率,调节抗氧化酶活性,缓解中度盐胁迫下黄瓜幼苗的氧化应激损伤,提高其耐盐性。

【Objective】The study aimed to investigate the alleviating effect of H_(2)S on growth inhibition of cucumber seedlings under salt stress,providing scientific basis for cucumber salt-tolerant cultivation.【Method】Cucumber cultivar Xinchun No.4 was employed as the materials,which was water-cultured and NaCl(50 mmol/L)stressed in climatic chamber;and the leaves were sprayed with H_(2)S donor(i.e.,NaHS)of 200μmol/L and H_(2)S synthesis inhibitor PAG(DL-propargyl glycine,150μmol/L).【Result】Compared with the NaCl stress,the foliar spraying with NaHS could improve the growth of cucumber seedlings,the dry masses of above ground and underground increased by 29.12%and 48.52%,respectively;and the contents of soluble sugar and proline increased by 53.99%and 22.21%,and also,the content of photosynthetic pigment and chlorophyll fluorescence parameter Fv/Fmsignificantly increased.The contents of hydrogen peroxide(H2O2)and malondialdehyde(MDA)decreased by 37.79%and 24.27%,respectively,and the antioxidant enzymes activity also decreased,while these indexes exhibited the opposite change in the PAG-treated cucumber seedlings.【Conclusion】H_(2)S can increase the accumulation of osmotic regulatory substances,mitigate the loss of photosynthetic pigments,maintain the maximum photochemical efficiency of PSII,regulate the activity of antioxidant enzymes,and alleviate the damage of oxidative stress to cucumber seedlings under moderate salt stress,and whereby improve salt tolerance of cucumber plants.