【摘要】 青花菜采后花蕾中可溶性蛋白质和ＡｓＡ（抗坏血酸）含量，ＳＯＤ（超氧物歧化酶）和ＬOX（脂氧合酶）活性不断下降，膜脂过氧化加快，引起了衰老。外源ＡｓＡ对花蕾的延衰效应依处理浓度及次数而异，１００ｍｇ／ＬＡｓＡ稍有延衰作用，５０ｍｇ／ＬＡｓＡ延衰作用不明显，２００ｍｇ／ＬＡｓＡ、１００ｍｇ／ＬＡｓＡ每日连续喷施均促进衰老。较低浓度ＡｓＡ的延衰效应主要与延缓内源ＡｓＡ降解、激活ＳＯＤ活性有关，ＬＯＸ活性降低所起的作用并不重要；较高浓度ＡｓＡ促进衰老可能与引起ＳＯＤ活性下降及促进Ｆｅｎｔｏｎ反应，形成氧化力更强的，ＯＨ自由基有关。更多还原

【Abstract】 After the harvesting of broccoli,the contents of toluble protein and ascorbic acid( AsA)together with the activities of superoxjide dismutase(SOD)and lifxjxldase(LOX)decreased constantly; lipid peroxidation increased,caus-ing senescence in the flower buds. The effects of exogenous AsA on deferring the senescence varied with different AsA concentrations and times of treatment. 100mg/L AsA deferred the senescence slightly; 50mg/l AsA didn’ t show evi-dent deferring effect;while 200 mg/L and 100mg/L AsA with daily treatment promoted the senescence. The defer-ring effect of lower AsA concentration on the senescence was mainly related to the delay of endogenous AsA degradation and the stimulation of SOD activity. The decrease of LOX activity didn’t play an important role in deferring senes-cence. The promoting effect of higher AsA concentration on the senescence was probahly related to thedecrease of SOD activity,the promotion of Fenton reaction and the formation of free radical.OH which had stronger oxidizing force.更多还原