Complex sentence: The accumulation of hexose sugars (glucose, fructose) is associated with the development of xylem cell discontinuities which reduce the volume of water entering the berry relative to the volume of sugar, resulting in an increase in sugar concentration.
Split into simpler sentences: The accumulation of hexose sugars (glucose, fructose) is associated with the development of xylem cell discontinuities. These discontinuities reduce the volume of water entering the berry relative to the volume of sugar, resulting in an increase in sugar concentration.