Abstract: In order to explore the inhibitory effects of nitric oxide on lipid peroxidation in flue-cured tobacco under drought stress, the pot experiment was carried out to investigate the effects of different concentrations of exogenous NO donor (sodium nitroprusside, SNP) on the membrane permeability of leaf and root system of flue-cured tobacco, MDA content, antioxidant enzyme activity and content of osmotic adjustment substances under drought stress. The results showed that membrane permeability of leaf and root system, the contents of MDA, soluble protein, soluble sugar, proline (Pro) and K+, and the activities of superoxide dismutase (SOD) and catalase (POD) of the leaves and roots of tobacco increased significantly under drought stress, while the content of catalase (CAT) decreased significantly. The membrane permeability of leaf and root system and MDA content decreased significantly after spraying 0.25 mmol/L and 0.5 mmol/L, while the activity of antioxidant enzymes and content of osmotic adjustment substances increased significantly. This indicated that exogenous SNP could effectively improve the activity of antioxidant enzymes and content of osmotic adjustment substances, maintain the stability of cell membrane, and alleviate the oxidative damage of lipid membranes of flue cured tobacco under drought stress. It also showed that the concentration effect of SNP on alleviating drought damage, and different organs of flue-cured tobacco had different response to SNP concentration.

Key words: flue-cured tobacco, nitric oxide, drought stress, lipid, antioxidant enzyme

摘要： 为探究一氧化氮（NO）在干旱胁迫下对烤烟脂膜过氧化的抑制效应，采用盆栽试验研究了不同浓度NO供体硝普钠（sodium nitroprusside, SNP）对干旱胁迫下烤烟叶片和根系膜透性、MDA含量、抗氧化酶活性及渗透调节物质含量的影响。结果表明：干旱胁迫下，烤烟叶片和根系膜透性，丙二醛（malondialdehyde, MDA）、可溶性蛋白、可溶性糖、脯氨酸（proline, Pro）、K+含量以及超氧化物歧化酶(superoxide dismutase, SOD)、过氧化物酶（peroxidase, POD）活性明显提升，过氧化氢酶（catalase, CAT）显著降低；喷施0.25 mmol/L和0.50 mmol/L SNP分别使烤烟叶片、根系膜透性和MDA含量显著降低，抗氧化酶活性和渗透调节物质含量显著增加。说明外源SNP能有效提高烤烟抗氧化酶活性和渗透调节物质含量，维持细胞膜系统稳定性，缓解干旱胁迫对烤烟细胞脂膜的氧化损伤，同时SNP在缓解干旱损伤时具有浓度效应，且烤烟不同器官对SNP浓度响应不同。

关键词: 烤烟, 一氧化氮, 干旱胁迫, 脂膜, 抗氧化酶