The Growth and Development of 'Mini Chal' Tomato Plug Seedlings Grown under Monochromatic or Combined Red and Blue Light-Emitting Diodes

Abstract

This study was conducted to examine the effects of monochromatic or combined LEDs lighting on the growth and development of tomato plug seedlings. 'Mini Chal' tomato (Solanum lycopersicum L.) seedlings were grown under diniconazole or various light quality treatments [fluorescent lamp (FL), 150 mg.L-1 diniconazole treatment under FL (Dini), and combination of red (R) and blue (B) LEDs as follows: R:B = 100: 0 (R), R:B = 70: 30 (R7B3), R:B = 50: 50 (R5B5), R:B = 30: 70 (R3B7), or R:B = 0: 100 (B)] for 23 days. Combined R and B lighting resulted in shorter plants except for Dini, and monochromatic or combined LEDs lighting led to thickened stems than Dini. High R light environments resulted in the highest number of leaves. The leaf area was lower for plants in all LEDs environments and Dini compared to plants in FL. Dini and all LEDs environments except B increased the leaf thickness, with the thickest leaves observed for seedlings in R3B7 among LEDs treatments. The fresh and dry weights were the highest for plants in R and R3B7, respectively. Dini, R5B5, and R3B7 slightly increased the dry matter of plants. Combined LEDs environments increased the compactness, with R3B7 resulting in the largest increase. After transplanting to hydroponics culture systems, combined LEDs lighting induced accelerated flowering of the first and second clusters. In conclusion, the results of this study suggest that R3B7 is the most suitable light environment to produce high-quality 'Mini Chal' tomato plug seedlings.