Effects of Red and Blue LED Light Ratio on Growth and Photosynthesis of Tomato.

The tomato variety 'Provence' was used as the material, and the artificial light supplement test was carried out in the double-arch steel frame solar greenhouse, and T1 (2R3B, the ratio of red/blue light beads R:B=2:3), T2 (4R1B), T3 (6R1B), T4 (7R1B) four groups of red and blue light treatments were set up, and no artificial light was used as the control (CK) to explore the optimal red and blue light ratio for greenhouse tomato growth and photosynthetic response. The results showed that after 35 days of T1 treatment, the plant height, SPAD, transpiration rate (Tr) and photochemical quenching coefficient (qP) of tomato were significantly increased by 26.7%, 19.6%, 107.6% and 34.3%, respectively, compared with the control group. After 35 days of T3 treatment, the stem diameter, flower number, net photosynthetic rate (Pn), intercellular CO2 concentration (Ci), stomatal conductance (Gs), actual photochemical efficiency (ΦPSII) and electron transport rate (ETR) of tomato were significantly increased by 26.9%, 38.6%, 133.7%, 5.9%, 183.3%, 31.3% and 30.9%, respectively, compared with the control group. After 35 days of T4 treatment, the maximum photochemical efficiency (Fv/Fm) was significantly increased by 4.0% compared with the control group. Compared with the control group, the growth and photosynthesis of tomato could be significantly promoted under different red and blue light supplement treatments. Among the four red and blue combination light treatments of 2R3B, 4R1B, 6R1B and 7R1B in this experiment, the comprehensive effect of each index under 6R1B treatment was the best, which could provide some theoretical guidance for LED light supplement in greenhouse tomato cultivation. [ABSTRACT FROM AUTHOR]