Rare earth transfer films enhance the photosynthetic efficiency of strawberry plants, thereby improving fruit quality and yield

Strawberry (Fragaria × ananassa Duch.) is an important crop in the world. Environmental fluctuations have a significant impact on the growth of strawberries. Photoconversion films can change the environment of facility crops to increase production and improve quality. Therefore, this study investigated the effects of rare earth light conversion films (RPOs) on strawberry cultivation. The temperature, photosynthetic photon flux density, light transmittance and proportion of spectra beneficial to the crop production of RPO greenhouses were all greater than those of the control. Compared with those of the control, spongy tissues were sparser in RPO1 and RPO2 leaves. The cross-sectional surface area of the main vascular bundles of strawberry petioles treated with RPO1 and RPO2 increased slightly. Compared with those of the control, net CO₂ assimilation, stomatal conductance, activity of Rubisco and gene expression levels of RPO1 and RPO2 were all increased, and the intercellular CO₂ concentration was decreased. Compared with those of the control, yield, soluble solids, soluble sugar content, Vc content, and flavonoid contents of RPO1 and RPO2 increased, while the soluble protein content decreased. In conclusion, RPO promotes photosynthesis in strawberry plants by optimizing photosynthetic photon flux density, spectrum and temperature in greenhouses; adjusting the spectrum to change pigment content, spongy tissue structure, petiole vascular bundles, and Rubisco activity; and regulating the expression of the Rubisco gene, thereby increasing the quality and yield of strawberry plants. Compared with RPO1, RPO2 could be a more suitable film for strawberry production.