Special research on LED plant fill light to promote plant growth

In the past ten years, the indoor planting area has developed rapidly, and the lighting technology of supplementary light environment control for plant growth has attracted attention. Plant fill light lighting technology is mainly used in two aspects:
1. Use as supplementary lighting for plant photosynthesis when the amount of sunshine is small or the sunshine time is short;
2. Induced lighting as plant photoperiod and photomorphology.

Research on LED plant supplementary lighting as supplementary lighting for plant photosynthesis Traditional artificial light sources generate too much heat, such as LED supplementary lighting and hydroponic systems, air can be recycled, and excess heat and water can be removed , electrical energy can be efficiently converted into effective photosynthetic radiation, and finally into plant matter. Studies have shown that the growth rate and photosynthetic rate of lettuce can be increased by more than 20% by using LED plant fill light lighting. It is feasible to use LED plant fill light in plant factories.
 
The study found that compared with fluorescent lamps, LED plant supplementary light with mixed wavelengths can significantly promote the growth and development of spinach, radish and lettuce, and improve morphological indicators; it can maximize the bioaccumulation of sugar beet, and the accumulation of betalain in hairy roots is the most significant. The highest sugar and starch accumulation occurred in hairy roots.
 
Compared with metal halide lamps, the anatomical morphology of stems and leaves of pepper and perilla plants grown under LEDs with wavelengths changed significantly, and with the increase of optical density, the photosynthetic rate of the plants increased. LEDs with composite wavelengths caused an increase in the number of stomata in marigold and sage plants.

LED plant fill light as a plant photoperiod and light form to induce lighting with specific wavelengths of LEDs can affect the flowering time, quality and duration of flowering of plants. Certain wavelengths of LEDs can increase the number of flower buds and flowering of plants; certain wavelengths of LED plant fill light can reduce the flower formation response, regulate the length of the pedicel and the flowering period, which is conducive to the production and marketing of cut flowers. It can be seen that the flowering and subsequent growth of plants can be regulated by LED regulation.

Research on LED application in aerospace ecological life protection system Establishing a Controlled Ecological Life Support System (CELSS) is the fundamental way to solve the problem of long-term manned space life support. The cultivation of higher plants is an important element of CELSS, and one of the keys is light.

 
Based on the special requirements of the space environment, the light source used in the cultivation of higher plants in space must have high luminous efficiency, output light waves suitable for plant photosynthesis and morphogenesis, small size, light weight, long life, high safety and reliability records and no environment pollution, etc. Compared with other light sources such as cool white fluorescent lamps, high pressure sodium lamps and metal halide lamps, LED plant fill lights can more effectively convert light energy into photosynthetically active radiation; in addition, it has a long life, small size, light weight and solid state. Therefore, it has been paid much attention in the cultivation of ground and space plants in recent years. Studies have shown that the LED plant fill light lighting system can provide lighting with uniform spectral energy distribution, and the efficiency of converting electrical energy into the light required by plants is 520 times higher than that of metal halide lamps.