Abstract: In order to understand the difference of physiological responses to drought stress between oat （Avena sativa L.） awned mutant obtained by chemical mutagenesis and its wild type， the awnless wild type and its M₅ awned mutant of ‘Everleaf’ were used as materials. A pot experiment with controlled soil moisture was carried out to analyze the antioxidant and photosynthetic physiological indexes at seedling stage， tillering stage and jointing stage by setting 75%， 60% and 45% field water holding capacity. The results showed that genotype， water stress and growth stage had significant effects on each index. Under drought conditions， the activities of superoxide dismutase （SOD）， catalase （CAT） and peroxidase （POD） in the awned mutant were significantly increased， while the content of malondialdehyde （MDA） was decreased. At the same time， the net photosynthetic rate （Pn） and water use efficiency （WUE） were maintained at a high level， and Pn increased by 20.27% under severe stress at jointing stage. In addition， the actual quantum yield of PSⅡ （ΦPSⅡ） and relative electron transport rate （ETR） of the mutant was increased， while the non-photochemical quenching （NPQ） was decreased. In conclusion， the oat awned mutant enhances drought resistance by enhancing antioxidant capacity and maintaining photosystem stability.

Key words: Oat, Awn, Drought stress, Antioxidant enzymes, Photosynthetic characteristics, Chlorophyll fluorescence

摘要： 为了解化学诱变获得的燕麦（Avena sativa L.）具芒突变体及其野生型对干旱胁迫的生理响应差异，以‘爱沃’无芒野生型及其M₅代具芒突变体为材料，采用盆栽控水试验，设置75%，60%和45%田间持水量，分析苗期、分蘖期和拔节期的抗氧化及光合生理指标。结果表明：基因型、水分胁迫和生育时期对各指标具有显著影响。干旱条件下，具芒突变体的超氧化物歧化酶（Superoxide dismutase，SOD）、过氧化氢酶（Catalase，CAT）和过氧化物酶（Peroxidase，POD）活性显著升高，丙二醛（Malondialdehyde，MDA）含量降低；同时维持较高的净光合速率（Net photosynthetic rate，Pn）和水分利用效率（Water use efficiency，WUE），在拔节期重度胁迫下Pn提高20.27%。此外，突变体的PSⅡ实际量子产量（Actual quantum yield of PSⅡ，ΦPSⅡ）和相对电子传递速率（Relative electron transport rate，ETR）有所提高，非光化学淬灭系数（Non-photochemical quenching，NPQ）降低。具芒突变体通过增强抗氧化能力和维持光系统稳定性，提高了抗旱性。

关键词: 燕麦, 芒, 干旱胁迫, 抗氧化酶, 光合特性, 叶绿素荧光