外源H2S对盐胁迫下红砂幼苗叶片和根系氮代谢的影响

H₂S作为新型气体信号分子在调控植物生长发育和抗逆境胁迫中发挥着重要作用。为探究外源H₂S对盐胁迫下红砂(Reaumuria soongorica)氮代谢的影响机制及最佳叶施浓度，以当年生红砂幼苗为材料，采用盆栽试验，以1/2 Hoagland浇灌为对照(CK)考察在300 mmol·L^-1NaCl胁迫(CK300)下，叶面喷施不同浓度(0、0.010、0.025、0.050、0.100、0.250、0.500、1 mmol·L^-1)H₂S供体硫氢化钠(NaHS)对红砂叶片和根系中硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸合成酶(GOGAT)活性以及硝态氮、可溶性蛋白和游离氨基酸含量的影响。结果表明，盐胁迫下，红砂幼苗根、叶中可溶性蛋白、游离氨基酸、硝态氮含量以及NR、GOGAT、GS活性均较对照(CK)显著下降。经不同浓度外源H₂S处理后，红砂根、叶中可溶性蛋白含量与单独盐胁迫对照(CK300)相比显著降低，NR、GOGAT、GS活性和硝态氮、游...

Effects of Exogenous H2S on Nitrogen Metabolism in Leaves and Roots of Reaumuria Soongorica Seedlings Under Salt Stress

H₂S （hydrogen sulfide）， as novel gas signaling molecule， plays an important role in regulating plant growth and resisting stress. In order to investigate the response mechanism of exogenous H₂S to nitrogen metabolism and the optimal foliar spraying concentration of Reaumuria soongorica under salt stress， we choose the current-year R. soongorica seedlings as test material to measure the activities of nitrate reductase （NR）， glutamine synthase （GS）， glutamate synthase （GOGAT） and concentrations of nitrate nitrogen， soluble protein and free amino acid in leaves and roots by different concentrations of H₂S （0， 0.010， 0.025， 0.050， 0.100， 0.250， 0.500 and 1 mmol·L^-1 sodium hydrosulfide） under 300 mmol·L^-1 NaCl stress in this pot experiment. The results showed that the concentrations of soluble protein， free amino acid and nitrate nitrogen and the activities of NR， GOGAT and GS decreased significantly compared with CK under salt stress in roots and leaves of R. soongorica seedlings. The content of soluble protein in roots and leaves of R. soongorica treated with different concentrations of exogenous H₂S significantly decreased compared with the salt stress control alone （CK₃₀₀）， while activities of NR， GOGAT and GS， content of nitrate nitrogen and free amino acid increased significantly. Comprehensive analysis showed that NR and GS could be used as the main evaluation indexes for the alleviating effect of H₂S under salt stress on R. soongorica seedlings. And the optimal alleviating concentration of exogenous H₂S was 0.025 mmol·L^-1 under salt stress for R. soongorica seedlings. In conclusion， the appropriate exogenous NaHS could effectively alleviate the inhibition function of nitrogen metabolism under salt stress on R. soongorica seedlings. This study provided an important theoretical basis for further understanding the mechanism of salt tolerance and breeding of high quality germplasm resources of R. soongorica.