Changes in neutral sugars and pectin-related materials during ripening of sour cherry fruit
Z. Gao, S.-D. Yoo, S. van Nocker, and W. Loescher
Proceedings of 26th International Horticultural Congress. Volume of Abstract . Toronto, Canada, 11-17 August, 2002. Abstract S09-P-154. pp. 260-261.
2002
บทคัดย่อ
Sour cherry (Prunus cerasus) fruit lose firmness in a few days, causing problems during mechanical harvesting and processing. We evluated changes in cell wall composition during fruit development. Fruit were collected throughout development and ripening. Mesocarp tissues were extracted to yield phenol:acetic acid:water (PAW) –soluble and other cell wall materials (CWM). Cell wall analyses showed several distinct changes in the mass of CWM, with a net increase becoming a sharp decrease at 36-40 days after pollination. These changes were associated wity CDTA- and Na CO2-solubilized CWM, the pectin-related components, along with PAW –soluble materials. During development, arabinose was the major neutral sugar in CDTA and Na CO2 fractions; other sugars were minor components. Using gel-filtration chromatography we analyzed neutral sugars and of PAW and CDTA-solubillized CWM. With ripening, pectins and neutral sugars increases in PAW, and these were present in a broad range of high to low molecules. Arabinose was the major neutral sugar in high fractions, but glucose was the major component of small fractions. In CDTA-solubillized CWM in young fruit pectins were broadly distributed across the range of eluted fractions. Later, however, small and intermediate pectins were sequentially solubillized, leaving only high pectins in mature fruit. Ripening thus involves removal of arabinose and glucose rich side chains from pectins, resulting in pectin depolymerization and increasing pectin-related solubility. These developmental and ripening related changes in cell walls are entirely consistent with changes in gene expression of a broad range of cell wall modifying enzymes.