2021 Volume 65 Issue 1 Pages 29-40
Sugar content is an important consideration when evaluating the quality of strawberry fruit and is governed by the interaction between the plant and its environment during growth. In this study, we examined the reproductive growth rate of strawberry and its relationship with sugar accumulation in the fruit under different phosphorus concentrations (2, 6, and 12 mM) and light spectra (purple light-emitting diode [LED] light [PL], white LED light [WL], and white fluorescence light [WF]) under plant factory conditions. In the early growth stage, the plants grew best with the P6WL treatment, which led to a low relative growth rate (RGR) in the reproductive stage. During the reproductive period, the net assimilation rate had a major effect on the difference in RGR among treatments and was mainly controlled by the phosphorus concentration. Relative allocations of RGR to vegetative and reproductive growth rate were impacted by both of phosphorus concentration and light spectrum; 6 or 12 mM phosphorus and white spectra enhanced the reproductive growth rate, while 2 mM phosphorus and PL significantly improved the vegetative growth rate of the plants. A high reproductive growth rate together with high sucrose phosphate synthase activity resulted in higher levels of fruit sugar accumulation, with the reproductive growth rate and sugar accumulation being highest in the P6WL treatment and lowest in the 12WF treatment. Therefore, we demonstrated that controlling the phosphorus concentration and light spectrum could direct plant growth and fruit sugar accumulation in strawberry.
