毛竹种子人工老化过程中生理生化变化

摘要

研究人工老化过程中毛竹种子活力及其生理生化变化过程.结果表明:人工老化处理后,种子发芽率、发芽指数和活力指数均先快速下降后缓慢下降,活力指数下降较发芽率和发芽指数快.老化6天时活力指数下降72％,老化12天时种子活力基本丧失.伴随着种子活力下降,表现出种子浸出液相对电导率和可溶性糖含量升高,MDA含量升高,POD,SOD和CAT酶活性降低,可溶性蛋白质含量降低,内源GA3和IAA含量降低,ABA含量升高,GA3/ABA比值降低等一系列生理生化变化.相关分析表明:SOD活性、CAT活性、可溶性蛋白和GA3,IAA,GA3/ABA,与种子活力呈极显著正相关;种子浸出液相对电导率、MDA和ABA含量呈极显著负相关.膜脂过氧化引起的生物膜损伤是加速毛竹种子老化的重要原因,内源激素失衡也是影响种子萌发和加速老化的主要因素之一.%The seed vigor of moso bamboo (Phyllostachys edulis) and the physiological and biochemical changes involved in seed deterioration were investigated in this article.The results showed that the germination rate,germination index,and vigor index all decreased rapidly in the beginning and slowly later in response to the artifical aging.The vigor index of seeds decreased more rapidly than the germination rate and germination index.The vigor index of moso bamboo seeds decreased by 70％ after 6 days of artificially accelerated aging,and lost almost all after 12 days of artificially accelerated aging.With the seed vigor declining,the physiological and biochemical changes were observed.The relative electric conductivity of the seed leachate,soluble sugar content,and MDA content of the seed extract were increased,while the soluble protein content,and the activity of antioxidant enzymes SOD,CAT and POD were declined.The content of GA3 and IAA,and GA3/ABA ratio were decreased.The correlation analysis indicated there was a very significant positive correlation between the activity of antioxidant enzymes SOD and CAT,the soluble protein content,the content of GA3 and IAA,GA3/ABA ratio and the seed vigor,while there was a very significant negative correlation between the relative electrical conductivity,MDA content,ABA content and the seed vigor.It was suggested that the injury to the membrance integrality caused by peroxidation of membrane lipids was one the main mechanisms to cause or accelerate seed deterioration in the artificial aging.The balance loss of endogenous hormones also played an important role in influencing seed germination and speeding up the seed deterioration.