Photosynthesis and leaf development of cherry tomato seedlings under different LED-based blue and red photon flux ratios

We investigated the photosynthesis and leaf development of cherry tomato seedlings grown under five different combinations of red and blue light provided by light-emitting diodes (LEDs). Fresh biomass increased significantly under treatments with blue light percentages of 50, 60, and 75%, with 50% blue-light-grown seedlings accumulating significantly more dry mass. The 25% blue-light-grown seedlings were obviously weaker than those from the other LED treatments. An increase in net photosynthetic rate upon blue light exposure (25-60%) was associated with increases in leaf mass per unit leaf area, leaf area, leaf density, stomatal number, chloroplast and mesophyll cell development, and chlorophyll contents. Our results imply that photosynthesis and leaf development in cherry tomato seedlings are associated with both the proportion and quantity of blue light.