Shiraz berry weight loss at the sub-optimal maturity – defining the problem

Abstract

Berries of Vitis vinifera L. cv Shiraz can undergo weight loss during later stages of ripening while other varieties such as Chardonnay and Sultana are less prone to this. Hydraulic characteristics of the xylem connections into developing berries were examined in Shiraz, Chardonnay and Sultana. Chardonnay tended to prevent back-flow by having a 10 fold lower conductance for flow out compared to flow in, while for Shiraz both directions of flow gave equal conductance. Cell vitality and the selectivity of cell membranes of the berry play a role in these phenomena so we examined the changes in cell vitality at key stages in development. There was a loss of cell membrane integrity during late ripening stages. The techniques developed may show differences in berry quality based on the pattern of cell death in the pericarp.

Summary

This project attempts to identify all factors contributing to the onset and extent of weight loss in Shiraz berries.