BASIC AND APPLIED RESEARCH APPROACHES FOR OPTIMIZING THE USE OF ARTIFICIAL LIGHT IN VEGETABLE CROPS

Light-emitting diode (LED) lights are a desirable alternative to outdated lighting systems due to their numerous benefits, including programmability and efficiency in energy consumption. But before switching from traditional broad-waveband lighting systems to narrow-wavelength LED lighting, there is a need to ensure that the new lighting system can produce the plants with better or at least the same yields and quality. Moreover, to select appropriate light "recipes," or wavelength combinations, for the best possible plant growth, one must first comprehend the effects of light quality on plant development. The following work delved into the broad range of spectrum from UV-B to infrared with an objective to investigate the effect of various wavelengths and their morphological, physiological, transcriptomics as well as metabolomics effects on the produce. For this purpose, several crop species were given importance such as spearmint, red rubin basil, red and green lettuce, tomato, arugula and wild rocket respectively. While it is a fact that HPS lighting benefited horticulture for a considerable amount of time, a comparison of various morphological, physiological, and quality attributes was made between HPS lighting, LED, and LED assisted with infrared on crops like tomato and spearmint in one section of this study. The traits such as early and late flowering, tomato fruit weight, lycopene, beta carotene, brix index, titratable acidity, phenolic index, anthocyanins, chlorophyll a and b, carotenoids, total sugars, reducing sugars, sucrose as well as TBARS were considered to observe the effects of different supplemental lighting systems. Furthermore, another important aspect of artificial lighting such as energy consumption was evaluated from the standpoint of using pulsed LED lighting on crops such as red and green lettuce. Pulsed frequencies of 2Hz and 1 KHz were considered and investigated for energy consumption and energy used efficiency against the continuous LED treatment in addition to the morpho-physiological evaluation of the produce. Also, another important spectrum, far-red (FR) light in combination with the diurnal temperature fluctuations (DIF) treatments were analyzed while working on arugula and lettuce crops. Additionally, the use of blue light as low and high blue light in the total photon flux density (TPFD) was evaluated in accordance with the shade avoidance response of the crops for both FR light and temperature fluctuations. Morphological, physiological and phytochemical analyses were performed to strengthen the debate about the use of interactive effect between FR light and DIF treatments in the light of low and high blue light. Likewise, the role of the UV-B light in terms of secondary metabolites productions was assessed in multiple crops such as spearmint, red rubin basil and spearmint. Several UV-B doses were selected and investigated for crops responses through morphological, physiological (for wild rocket, red rubin basil and spearmint) in addition to the metabolomics and transcriptomics (wild rocket only) responses. Results indicated that several genes were up and down regulated due to the UV-B treatments and plants' primary and secondary responses to UV-B elicitation can be a key for the improvement of secondary metabolites in the controlled environment agriculture. Finally, it is concluded that the role of artificial lighting, in terms of the wavelengths from the UV-B to the infrared, can play a key role in the horticultural production and global food production and food security.