Photosynthetic performance of strawberry acclimated to the solar spectrum modified by spectrum conversion film in greenhouses

Functional films have been used in greenhouses to improve the light environment for plant growth. A spectrum conversion film (SCF) converting the green light into red light has been introduced to improve the photosynthesis and crop productivity in greenhouses. However, the reasons for the improvement are not fully investigated. The objective of this study was to reveal the effects of the SCF on the electron transport and photosynthetic performance of strawberry. The photosynthetic efficiency, chlorophyll fluorescence, growth, and fruit qualities when the plant was grown under a commercial polyethylene film (PE) and SCF were compared. SCF significantly increased the efficiency of electron transport and the reduction end electron acceptors at photosystems I (PSI) acceptor side. The electron transport rate of PSI and PSII of leaves grown under the SCF were significantly higher than those grown under the PE. Accordingly, the photosynthetic light response curve and photosynthetic rates of leaves increased significantly under the SCF compared to the PE. The growth of strawberry plant was not different, but the fruit weight, sweetness, acidity, and firmness grown under the SCF were significantly improved. These results indicated that the solar spectrum modified by SCF improves electron transport, photosynthetic performance, and fruit quality of the strawberry.