Abstract: The tomato variety 'Micro Tom' is used as an experimental material in a fully artificial light-type plant factory. An LED light with adjustable illumination modes was used as the light source and a pure white LED light was used as the control. Different illumination mode, such as pure red light, pure blue light, mixed red and blue light, and alternating red and blue light were used as supplementary light. The influence of different red and blue supplemental lighting modes on the growth, development, and fluorescence characteristics of greenhouse tomatoes was explored. The results showed that: (1) in all treatments, the growth indicators and fruit weight of the tomato plants increased to a certain extent. The dynamic change of chlorophyll fluorescence was significantly affected by supplementary light. Pure red light supplementation had the greatest effect on the increase in plant height, stem thickness, leaf area, and yield of the tomato plants. Alternating red and blue light supplementation at intervals of 1h or 6h significantly promoted the increase in chlorophyll content and the improvement of PSII photosynthetic performance. (2) During the vegetative growth stage of tomatoes, under pure red light supplementation, the relative growth rate and absolute growth rate of plant height increased by 106.8% and 60% respectively compared to the control. The relative growth rate and absolute growth rate of stem thickness increased by 50% and 80% respectively. 44 days after sowing, the leaf area of the tomato plants under pure red light supplementation increased by 92.1% compared to the control.(3) During the reproductive growth period of tomatoes, compared with the control, 83 days after sowing, the number of fruits set under pure red light supplementation increased by 73.6%. The horizontal and vertical diameters and volume of tomato fruit increased by 34.4%, 35.3%, and 129.6% respectively.(4) Compared with the control, 44 days after sowing, the chlorophyll content in tomato leaves under alternating red and blue light supplementation at intervals of 1h or 6h increased by 30.3% and 31.8% respectively. 83 days after sowing, the performance index (PI_ABS) of tomato plants after alternating red and blue light supplementation at intervals of 1h or 6h increased by 100% and 30% respectively compared to the control. The electron transfer efficiency (ET_o/CS) of PSII after alternating red and blue light supplementation at intervals of 1h or 6h increased by 16% and 23% respectively compared to the control. In summary, pure red light supplementation can effectively promote the growth and development of facility tomatoes. Alternating red and blue light supplementation at intervals of 1h or 6h significantly affects the fluorescence characteristics of tomatoes. In the future, the most suitable supplementary lighting mode can be chosen based on different production objectives.

Key words: Plant factory, Light supply mode, LED light, Growing period, Chlorophyll