Research on LED Application in Plant Facility Cultivation

As of 2013, the area of facility horticulture in China has developed rapidly, and the lighting technology for controlling the light environment of plant growth has attracted attention. Facility horticultural lighting technology is mainly applied in two aspects: firstly, it serves as supplementary lighting for plant photosynthesis when the sunlight is low or the sunlight duration is short; 2, As an induced illumination for the photoperiod and photomorphology of plants.
1. The study of LED as supplementary lighting for plant photosynthesis. Traditional artificial light sources generate too much heat, such as using LED supplementary lighting and hydroponic systems. Air can be recycled, excess heat and water can be removed, and electrical energy can be efficiently converted into effective photosynthetic radiation, ultimately converting into plant matter. Research has shown that using LED lighting can increase the growth rate and photosynthetic rate of lettuce by more than 20%, making it feasible to use LED in plant factories. Research has found that compared to fluorescent lamps, mixed wavelength LED light sources can significantly promote the growth and development of spinach, radish, and lettuce, and improve morphological indicators; It can maximize the biological accumulation of sugar beets, with the most significant accumulation of betaine in the hairy roots, and produce the highest accumulation of sugar and starch in the hairy roots. Compared with metal halide lamps, pepper and perilla plants grown under LED wavelengths exhibit significant anatomical changes in their stems and leaves, and their photosynthetic rate increases with increasing light density. Composite wavelength LED can cause an increase in the number of stomata in both marigold and sage plants.
2. LED, as an induction lighting device for plant photoperiod and light morphology, can affect the flowering time, quality, and duration of the flowering period of plants at specific wavelengths. LEDs of certain wavelengths can increase the number of flower buds and flowers in plants; LED of certain wavelengths can reduce the flowering reaction, regulate the length and flowering period of flower stems, and facilitate cut flower production and marketing. It can be seen that LED regulation can regulate the flowering and subsequent growth of plants.