Effect of 1-methylcyclopropene treatment on chilling injury, fatty acid and cell wall polysaccharide composition in loquat fruit.

Loquat fruit was treated with 2.32 nmol L(-1) 1-methylcyclopropene (1-MCP) for 24 h at 20 degrees C, and then stored at 1 degrees C for 35 days to investigate the effect of 1-MCP treatment on chilling injury (CI) and fatty acid and cell wall polysaccharide composition. Loquat fruit developed CI, manifested as increased fruit firmness, internal browning and decreased extractable juice. These CI symptoms were reduced by 1-MCP treatment. 1-MCP-treated fruit exhibited higher levels of linoleic and linolenic acid and a higher unsaturated/saturated fatty acid ratio than control fruit during storage. The treatment also markedly delayed increase in alcohol insoluble residue, i.e. hemicellulose and cellulose. Meanwhile, the level of water- and CDTA-soluble pectins in treated fruit was higher than that in control. Our result suggested modifications of fatty acid and cell wall polysaccharide composition are associated with CI develpoment in loquat and 1-MCP treatment modulates the changes that seem to regulate the strength of cell wall and so to alleviate CI.