以陆地棉新陆早45号为材料,在盆栽和大田条件下,选择新疆夏季持续高温、高光照天气,利用外源甲醇水溶液对花铃期棉花进行叶面喷施处理,求证其对C3作物光合酶Rubisco(核酮糖-1,5-二磷酸羧化酶/氧化酶)以及对棉叶光合日变化参数的影响,探讨外源甲醇提高棉花光合效率的可能机理.结果表明,外源甲醇处理田间棉花后7～56 d检测期间,处理组棉叶Rubisco羧化活性提高60％以上;Rubisco含量提高10％.外源甲醇处理盆栽棉花后14～49 d检测期间,处理组棉叶的净光合速率和气孔导度均有明显增高,分别提高了15％和20％;处理组蒸腾速率提高幅度为7％～10％,其变化曲线为非双峰型,无明显波峰、波谷及午休现象;处理组8:00～17:00胞间CO2浓度持续下降,胞间CO2浓度变化与净光合速率变化在14:00时前呈负相关.%Gossypium hirsutum L.No.45 Xinluzao was used as test materials to prove the effects of exogenous methanol on Rubisco and photosynthetic diurnal variation in cotton in flower-bolling stage under sustainable high temperature and high light conditions and to discuss the possible mechanism for exogenous methanol increasing photosynthetic diurnal variation of cotton in summer of Xinjiang.The results indicated that when the cotton treated with exogenous methanol for 7-56 days,the Rubisco activities increased by above 60％ ;Rubisco content increased by 10％ in field cotton foliage;When the cotton in the pot treated with exogenous methanol for 14-49 dags,the net photosynthesis rate and intercellular CO2 concentration were increased by 15％ and 20％,respectively.The transpiration rate of methanol group increased by 7 ％-10 ％,whose variation curve was non-double peak type.The intercellular CO2 concentration of methanol group showed continue to decline from 8:00 to 17:00,comparing with control,and this change was negatively correlated with changes in the photosynthetic rate before 14:00.
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