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Changes in glycosidase activities during development and ripening of melon

1991; Elsevier BV; Volume: 1; Issue: 2 Linguagem: Inglês

10.1016/0925-5214(91)90006-w

1873-2356

B. Fils-Lycaon, Michel Buret,

Plant Physiology and Cultivation Studies

Changes in the activity of several glycosidases were studied in mesocarp tissues of muskmelon (Cucumis melo L., var. Alpha) during fruit ontogeny. Mesocarp tissue contained α- and β-D-galactosidase, α-D-mannosidase, β-D-glucosidase, β-D-xylosidase, α-L-arabinopyranosidase and α-L-arabinofuranosidase activities at selected stages during fruit development. The activities of α-D-galactosidase and β-D-xylosidase did not change significantly during ripening. The activities of α-D-mannosidase and α-L-arabinofuranosidase increased slightly from the turning to the ripe stages, while those of β-D-galactosidase, α-L-arabinopyranosidase and β-D-glucosidase increased significantly from the turning to the overripe stages. When expressed on a protein basis, all activities measured increased at the turning stage, but only those of β-D-galactosidase, α-L-arabinopyranosidase and β-D-glucosidase continued until the end of ripening and overripeness. Glycosidases whose specific activities increased or remained constant during the final stages of ripeness were mainly solubilised in a high-ionic-strength-extractable fraction. In contrast, those whose specific activity decreased towards full ripening were mainly solubilised using a low-ionic-strength extractant. A possible role for glycosidases in muskmelon softening is discussed.