Effect of light and carbon dioxide on photosynthesis, chlorophyll fluorescence, and fruit yield in strawberry (Fragaria x ananassa Duch.) plants

Abstract

BACKGROUND: The use of two-floor bench bed systems to improve the strawberry productivity in Korea is increasing. OBJECTIVE: This study aimed to investigate the effect of different combinations of light intensity and carbon dioxide (CO2) concentration on photosynthesis, chlorophyll fluorescence, and fruit yield in strawberry (Fragaria x ananassa). METHODS: A two-floor bench bed system was used for light intensity treatments. CO2 fertilizer was supplied, from December 5 to January 30, when the concentration in a greenhouse fell below 700 mu molmol(-1), while the control received only ambient CO2. RESULTS: Strawberry plants that were grown under high light intensity in the upper bed had a higher photosynthesis rate than plants grown under low light intensity in the bottom bed; however, light intensity had a negligible effect on the stomatal conductance (Sc) and transpiration rate (Tr) of strawberry leaves. In contrast, CO2 fertilization lowered Sc and Tr values in strawberry leaves. Plants grown under low light intensity without CO2 fertilization had the highest chlorophyll fluorescence decrease ratio. Fruit yield was highest in plants grown under high light intensity, with CO2 fertilization having relatively little effect; however, CO2 fertilization stimulated the accumulation of anthocyanins. CONCLUSIONS: CO2 fertilization is effective in a two-floor bench bed system.