WATER POTENTIAL AND CELL TURGOR OF STRAWBERRY FRUIT ARE INFLUENCED BY RIPENING.

Abstract

Since large ripe strawberry fruit lose water faster than smaller unripe fruit, ripening fruit may out-compete unripe fruit for water within an inflorescence and thereby reduce yields. Xylem water potential (ψ) of greenhouse-grown `Brighton' fruit, at different stages of development, was measured with a pressure chamber during mid-afternoon. Large ripe and medium sized green-white fruit within an inflorescence had a more negative ψ than small green fruit. This suggests that small green fruit have a lower priority for xylem water moving into a strawberry inflorescence. Large ripe and small green fruit within an inflorescence had positive cell turgor (about 300 KPa), whereas turgor of medium sized green-white fruit was near zero, suggesting that these latter fruit were encountering greater water stress. When competing fruit on an inflorescence were removed, the calculated cell turgor was very similar to fruit with competition. Cell turgor of strawberry fruit is greatly influenced by developmental stage; this may moderate effects caused by water loss from neighboring fruit on an inflorescence.