Solute transport into Shiraz berries during development and late-ripening shrinkage

Shiraz berries commonly lose weight during the later part of ripening and loss of vascular flows into the berry may be a contributing factor. Changes in flow through the vascular streams were assessed by monitoring the accumulation of potassium and calcium in berries at the preveraison, postveraison, and shrinkage stages of development. Potassium, a predominantly phloem-mobile element, accumulated most strongly postveraison and less strongly during the shrinkage phase. Calcium, a xylem-mobile element, accumulated strongly before veraison, but after veraison accumulation patterns were variable. Girdling and excision of pedicels to remove phloem before and at the postveraison stage of development resulted in smaller berries but also inhibited the accumulation of sugars, pigments, and potassium, but not calcium, into the berry. With an assumption of ongoing transpiration, late-ripening shrinkage may be attributed to decreased phloem flow into the berry.