关键词: 鸭梨, 脂氧合酶, 果心褐变, 基因表达, 褐变指数

Abstract:

Hebei-grown Yali pears (Pyrus bretschneideri Rehd cv. Yali) of different maturities were stored at (0 ± 1) ℃
directly or after pre-cooling at gradually decreasing temperature. Changes in respiration intensity, ethylene production and
core browning index and lipoxygenase (LOX) activity and LOX gene expression pattern during storage were determined and
the relationship of LOX gene expression with core browning was studied as well. The results showed that during storage,
the decreasing order of LOX activity and core-browning index was as follows: late-harvested fruit > early-harvested fruit >
middle-harvested fruit, as well as rapid-cooling fruit > slow-cooling fruit. The expression level of LOX gene in core tissues
initially increased slowly, then declined, and increased again until the end of storage. The expression level of LOX gene in
rapid-cooling fruits was higher than in slow-cooling fruits, and the expression level of LOX gene in middle maturity fruits
was lower than in fruits of early and late maturities. Middle-maturity harvest combined with slow pre-cooling inhibited the
LOX gene expression of flesh and core tissues, thereby suppressing core browning of Yali pears. LOX activity and the gene
expression level of LOX were coordinated with core browning index, suggesting that the expression level of this gene was
correlated closely with core browning of Yali pears.

Key words: Yali pear, lipoxygenase, core browning, gene expression, core browning index