Abstract: Nitric oxide (NO) as a physiological active substance is widespread in organisms and can regulate a series of physiology and biochemical reactions of plant to enhance adversity resistance.The effects of sodium nitropprus-side (SNP,an exogenous nitric oxide donor) on growth and physiological characteristics were investigated in perennial ryegrass (Lolium perenne L.) seedling under osmotic stress (15%PEG-6000).Results showed that under osmotic stress (15%PEG-6000),0.1 mmol·L^-1 SNP significantly alleviated growth inhibition of perennial ryegrass seedling,accelerated accumulation of proline (Pro) and delayed water dissipation.The activity of superoxide dismutase (SOD),peroxidase (POD) and catalase (CAT) were enhanced and the content of malondialdehyde (MDA) were reduced significantly in perennial ryegrass seedling leaves under osmotic stress.The damage of perennial ryegrass seedlings caused by the osmotic stress of 15%PEG-6000 was significantly reduced by 0.1 mmol·L^-1 SNP.A higher concentration of SNP (0.5 mmol·L^-1) had less effect on growth and alleviating oxidative damage in perennial ryegrass seedlings.Exogenous nitric oxide induces changes in water content of leaves and antioxidant enzyme systems in plants,which is an important anti-adversity mechanism of plant physiology response to maintain natural growth under osmotic stress.

Key words: Perennial ryegrass (Lolium perenne L.), Nitric oxide (NO), Osmotic stress, Seeding growth, Physiological characteristics

摘要： 一氧化氮(Nitric oxide,NO)作为生物体广布的一种生理活性物质,可调节植物一系列生理生化反应,增强其对逆境的抵抗能力;为此,以15%PEG-6000模拟渗透胁迫,研究外源NO对多年生黑麦草(Lolium perenne L.)幼苗生长和生理特性的影响。结果表明:15%PEG-60000渗透胁迫下,0.1 mmol·L^-1NO供体硝普钠(Sodium nitroprus-side,SNP)可显著减轻对幼苗生长的抑制;促进脯氨酸(Pro)的累积,延缓幼苗叶片的水分散失(P<0.05);可诱导超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性升高,减缓丙二醛(MDA)的积累,显著缓解因渗透胁迫诱导的细胞膜脂过氧化过程(P<0.05),增强其抗渗透胁迫能力,且随着胁迫程度的加剧效果越佳。0.5 mmol·L^-1SNP处理对黑麦草幼苗生长影响不显著,促进保护酶活性及缓解氧化损伤的作用较0.1 mmol·L^-1SNP处理显著减弱。外源NO诱导植物水分及抗氧化酶系活性的变化,是植物在渗透胁迫下维持正常生长的重要抗逆生理机制。

关键词: 多年生黑麦草, 一氧化氮(NO), 渗透胁迫, 幼苗生长, 生理特性