关键词: 橄榄, 成熟度, 细胞壁组分, 细胞壁降解酶, 冷害

Abstract: Changes in the cell wall metabolism of Chinese olive fruits during cold storage were examined to explore the relationships between chilling injury and cell wall components and cell wall-degrading enzyme activities in four maturities of Chinese olive fruits. ‘Tanxiang’ Chinese olive (Canarium album (Lour.) Raeusch cv. Tanxiang) fruits harvested at the solar terms of White Dews, Cold Dews, Winter Begins and Heavy Snow were stored at (2 ± 1) ℃ and 85%–90% relative humidity. During storage, chilling injury index, cell wall component contents and cell wall-degrading enzyme activities in the fruit pulp were periodically determined. The results showed that the chilling injury symptoms were closely related to the degradation of cell wall components, and that the chilling injury index of fruits with different maturities was negatively correlated with the contents of ionic-soluble pectin (ISP), covalent-soluble pectin (CSP), semicellulose and cellulose. Cell wall structure disintegration, cell wall metabolism abnormality and chilling injury occurrence were in large part due to the imbalance of pectin methylesterase (PME) and polygalacturonase (PG) activities, as well as the increase of β-galactosidase (β-Gal) and cellulase (CEL) activities. Meanwhile, compared with maturities Ⅰ, Ⅲ, and Ⅶ, maturity Ⅴ could maintain lower chilling injury index during the entire storage and lower activities of PME, PG, β-Gal and CEL in pulp during the middle and late storage stages while retarding the decline in water-soluble pectin, ISP, CSP, semicellulose and cellulose. From these results, it can be concluded that maturity Ⅴ could maintain the integrity of cell wall structure and alleviate chilling injury symptoms in Chinese olive fruits during cold storage.

Key words: Chinese olive (Canarium album (Lour.) Raeusch), maturity, cell wall components, cell wall-degrading enzymes, chilling injury