超干贮藏对苤蓝种子抗氧化系统稳定性的影响

Effects of Ultradry Storage on the Stability of Antioxidation System of the Seed of the Seed of Brassica caulorapa Pasq.

超干处理苤蓝(BrassicacaulorapaPasq.)种子含水量由6.6%降至3.7%、1.5%,发芽率和活力指数均未受到影响,但抗老化劣变能力显著提高,超氧阴离子自由基(O·2)产生速率提高,对丙二醛(MDA)含量、抗氧化系统则无明显影响。经同等老化处理后,含水量为3.7%和1.5%的超干种子内的O·2自由基产生速率与MDA含量明显低于含水量为6.6%的对照种子;超干种子内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、愈创木酚过氧化物酶(GPX)和抗坏血酸过氧化物酶(APX)等酶活性保持完好,一旦吸胀萌动,迅速表现出活性,一起协同作用清除种子在贮藏过程中产生的活性氧自由基等有害物质,防止脂质过氧化伤害的发生,保证了种子正常快速萌发。

The effects of antioxidant system on the ultradry seed of Brassica caulorapa Pasq. were investigated. Ultradry treatment did not cause any changes in seed germination percentage and vigor index in the seed of B. caulorapa. Further more, it improved the storability of the seed during 30 days of accelerated ageing. Ultradry treatment enhanced superoxide generation rate, but did not affect the level of malondialdehyde (MDA) and the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) in B. caulorapa seed. After 10 days of ageing treatment at 50℃, both the superoxide generation rate and the MDA content were lower in ultradried seed than in the control. The content of ascorbic acid (AsA) was higher in ultradried seed than in the control. Once rehumidified and imbibed, the antioxidant enzymes in the ultradried seed played a very important role to scavenge the ultimate product of lipid peroxidation reduced during seed storage in order to maintain the seed germination ability. A more stable antioxidant system was maintained in ultradried seed, which should account for the high vigor of the ultradried seed.