Abstract: Changes of contents of soluble p rotein, free amino acid, O·2 and malondialdehyde (MDA) ,activities of superoxide dismutase ( SOD) , catalase (CAT) , and peroxidase ( POD) , ethylene production and polyamines contents in bract of two varieties of B ouga invillea glabra were investigated during senescence. The results showed that with the flower opening and senescence, the contents of soluble p rotein, free amino acid and polyamines, the activities of SOD, CAT and POD in B ougainvillea glabra bract were increased first and later decreased, free amino acid contents increased continually and decreased at lasting phase, O·2 generation rate and MDA contents had an ascend tendency and ethylene production changed according to climacteric character. The bract senescence of Bougainvillea glabra Choisy was the same with Bougainvillea spectabilis Willd approximately.

Key words: Bougainvillea glabra, Senescence, Antioxidant enzyme, Ethylene production, Polyamines content