蝴蝶兰花自然衰老与活性氧代谢的关系

摘要

以蝴蝶兰花的萼片、花瓣和唇瓣为试材,研究其自然衰老过程中活性氧及相关酶的生理变化,探索花朵衰老的主要因素.结果表明:萼片、花瓣和唇瓣从小蕾期至初开期的超氧化物歧化酶(SOD)和过氧化物酶(POD)活性没有表现出明显的变化,但在盛开期与衰败期二者活性显著升高；过氧化氢酶(CAT)活性在开花的各个时期总体表现为先下降后上升的趋势；从小蕾期至初开期,超氧阴离子(O2-·)的产生速率一直处于较低水平,盛开期开始明显上升,衰败期急剧增加；从小蕾期至初开期,H202质量摩尔浓度逐渐降低,衰败期质量摩尔浓度显著增加；可溶性蛋白质量浓度从小蕾期至衰败期逐渐降低；丙二醛(MDA)质量摩尔浓度从小蕾期到盛开期逐渐降低,盛开期达到最低,此后质量摩尔浓度迅速升高.在自然衰老过程中,萼片、花瓣和唇瓣三者的生理过程变化相似,但萼片最早,花瓣次之,唇瓣最慢.02-·是决定蝴蝶兰花衰老的主要因素.%The changes of reactive oxygen species concentration and the activities of antioxidant enzymes in the sepal, petal and palp of Phalaenopsis amabilis were investigated during senescence. The results show that from small bud to the beginning of flowering, the SOD and POD activities hardly change, but they increase significantly in the florescence and senescence stage. CAT activities decrease in the earlier stage and increase in the florescence and senescence stage in the sepal, petal and palp. Generating rate of O2-·hardly changes during earlier three stages, and then increases a little in the florescence and greatly in the last stage. H2O2 content decreases gradually in the beginning of the flowering, and then increases sharply in the last stage. Soluble protein content decreases gradually from small bud to senescence. MDA content decreases gradually from small bud to the beginning of flowering, and then increases greatly after florescence. Although similar changes happen in the sepal, petal and palp of P. amabilis, the senescence is found firstly in the sepal followed by the petal and palp. O2-· is the main factor during the senescence in P. amabilis.