梨外植体褐变与多酚氧化酶及酚类物质的关系

研究了苍溪梨、金花梨外植体多酚氧化酶（ＰＰＯ）活力、总酚含量和组培褐变率的变化规律及其关系。两品种的ＰＰＯ活力在１～９月间变化都成一单峰曲线，活力高峰出现在４月份。苍溪梨为１１１ｕ，金花梨为１５０ｕ，总酚含量两品种在不同的时期也表现出明显的差异。金花梨总酚含量高峰期出现在５月份，苍溪梨出现在４月份。同期组培褐变率表现为：两品种的褐变高峰均出现在５月份，苍溪梨为５４％，金花梨为７１％。分析三者的相关性表明：ＰＰＯ活力、总酚含量与组培褐变率都存在一定的关系，其组培褐变率的高低取决于ＰＰＯ活力和总酚含量两种因素，在不同的时期由其中之一起主导作用。

THE RELATIONSHIP BETWEEN BROWNING RATIO IN ETRO PPO AND PHENOLS OF PEAR EXPLANTS

The regulation and the relationship of PPO actvity phenol contents and browning ratio in vitro of Comgxili (Pyrus pyrifolia Nakoi) and Jin hua (P bretshneideri Rehd) explants were studied. The PPO activity of the two varieties shows single-peak curves during January to September and the peak values are 111u and 150u in April, individually. The phenol content peak of Jinhua is in May but that of Cangxili is in April. Browning ratio peak of Cangxili is in May and the value is 54%, but the value of Jinhua is 71%. In September the browning ratio of Cangxili presents another peak. The results showed that the PPO and phenol content are interrelated with browning ratio in vitro of the two varieties. The browning ratio is affected by the phenol content and PPO activity of explants. Which one was the main pact depends on the month. The browning ratio is resulted from PPO working on pherols.