Effect of fruit gas exchange on photosynthate accumulation and fruit growth of strawberries

Abstract

To clarify the effect of fruit gas exchange on photosynthate accumulation and fruit growth of strawberries (Fragaria × ananassa Duch.), fruit CO2 and H2O fluxes, and changes in fruit volume and sugar accumulation were investigated under limiting and non-limiting conditions of fruit gas exchange. By limiting fruit gas exchange with a combination treatment of calyx removal and vaseline coating, the daily integral values of fruit CO2 and H2O flux decreased to one-half of those in non-treatment. The limitations to fruit gas exchange remarkably inhibited translocation of sugars to fruits, and the concentration of total sugar (glucose + fructose + sucrose) in fruits was decreased below one-half of that in non-treated fruits. As a result, this inhibition of sugar accumulation to fruits under the limitation of fruit gas exchange brought a suspension of fruit growth. This suggests that not only leaf photosynthesis but also fruit gas exchange (respiration, transpiration) affect the sugar accumulation and growth of fruits through a process of photosynthates partitioning from leaves to fruits. It can be expected to achieve a higher strawberry productivity by the environmental control based on physiological responses of leaf photosynthesis and photosynthates translocation with the help of plant instruments.