Abstract: In order to explore the physiological response mechanism of Reaumuria soongorica salt tolerance under sparying different concentrations of nitric oxide donor sodium nitroprusside,the effects on growth,osmotic adjustment and membrane lipid peroxidation,R. soongorica seedlings were studied under 300 mmol·L^-1 NaCl stress by pot culture. The results showed that treatment with 300 mmol·L^-1 NaCl significantly inhibited the average plant height growth rate and biomass accumulation of R.soongorica (P<0.05). The content of soluble sugar (SS),proline (Pro),ion selective transport of K⁺ coefficients (ST _K+,Na+) and soluble protein (SP) were all reduced,while the content of malondialdehyde (MDA),Na⁺ and Na⁺/K⁺increased. Exogenous NO treatment can significantly improve the content of SS,Na⁺/K⁺ value and ST_K+,Na+, and decrease the content of Pro,SS,MDA. Exogenous NO at high concentration (>1.00 mmol·L^-1SNP) failed to alleviate the damage of NaCl stress,while low concentration (0.01~1.00 mmol·L^-1SNP) alleviated the inhibition of salt stress. Among all the experimental treatments,0.10 mmol·L^-1 sodium nitroprusside showed the best alleviation effect on salt stress. Exogenous NO treatment could significantly increase the SS content,Na⁺/K⁺ value and ST_K+,Na+,and reduce Pro,SP and MDA contents of R.soongorica under salt stress. These data suggested that NO mainly improved the salt tolerance of R.soongorica by increasing the content of plant SS and reducing the content of Pro and MDA. Meanwhile,NO can improve the adaptability of R.soongorica to the salt stress environment by promoting the selective absorption of the Na⁺ in R.soongorica and improving the transport capacity of K⁺ from the underground part to the above-ground part.

Key words: Nitric oxide, NaCl, Physiological response, Reaumuria soongorica

摘要： 本试验以当年生红砂（Reaumuria soongorica）幼苗为材料，采用盆栽实验，通过研究叶面喷施0.01~1.0 mmol·L^-1不同梯度NO供体硝普钠（sodium nitroprusside，SNP）对在300 mmol·L^-1 NaCl胁迫下红砂生长、渗透调节物质和膜脂过氧化程度的影响，以探讨外源NO对红砂耐盐性的生理响应机制。结果表明：300 mmol·L^-1 NaCl处理显著抑制了红砂植株平均株高生长速率和生物量的积累（P<0.05），降低了可溶性糖（Soluble sugar，SS）、脯氨酸（Proline，Pro）、离子选择向上运输K⁺的系数（ST_K+，Na+）和可溶性蛋白（Soluble protein，SP）含量，提高了丙二醛（Malondialdehyde，MDA）、Na⁺含量和Na⁺/K⁺值。外源NO处理可显著提高红砂在盐胁迫下的SS含量、Na⁺/K⁺值和ST_K+/Na+，降低Pro、SS、MDA含量。高浓度（>1.00 mmol·L^-1 SNP）外源NO未能缓解盐胁迫对红砂的伤害，而低浓度（0.01~1.00 mmol·L^-1 SNP）则有缓解盐胁迫对红砂生长抑制的作用，尤其以0.10 mmol.L^-1的NO供体SNP对盐胁迫的缓解作用最为显著。分析表明：NO主要通过提高植物SS的含量、降低Pro和MDA含量来提高红砂的耐盐性，同时，NO可通过促进Na⁺在红砂体内选择性吸收，提高地下部分K⁺向地上部分的输送能力来提高红砂对盐胁迫环境的适应能力。

关键词: 一氧化氮, NaCl, 生理响应, 红砂