LED Plant Growth Lamp Characteristics

- Jun 17, 2019-

LED plant growth lamp effect and different wavelength corresponding to what plant effect is better, greenhouse fruit LED lamp application.

1, the red light

In visible light, the most absorbed by green plants are red orange light (wavelength 600~700nm) and blue violet light (wavelength 400~500nm), while green light (wavelength 500~600nm) is only slightly absorbed. Red light is the first light quality used in crop cultivation and experiment, and it is the necessary light quality for normal growth of crops. The number of biological requirements ranks the first among all kinds of monochromatic light quality, and the most important light quality among artificial light sources. Substances produced in red light make plants grow taller, while substances produced in blue light promote the accumulation of proteins and non-carbohydrates, giving plants weight. Further infrared treatment reduced the concentration of anthocyanin, carotenoid and chlorophyll by 40%, 11% and 14% respectively, and increased the fresh weight, dry weight, stem length, leaf length and leaf width by 28%, 15%, 14%, 44% and 15% respectively. The formation of red light is regulated by photosensitive pigments. Red light drives photosynthesis through the absorption of photosynthetic pigments. Red light promotes the elongation of stem, the synthesis of carbohydrates, and the synthesis of VC and sugar in fruits and vegetables. But it inhibits nitrogen assimilation. But growing plants well alone is a bit harder.

2, blu-ray

Blue light is the necessary supplement of red light for crop cultivation, and it is necessary for the normal growth of crops. Blue light inhibits stem elongation and promotes chlorophyll synthesis, which is conducive to nitrogen assimilation and protein synthesis, as well as antioxidant synthesis. Blue light affects plant phototropism, light morphogenesis, stomatal opening and leaf photosynthesis. LED red light supplemented by LED blue light can improve dry matter quality of wheat, seed yield and lettuce dry matter quality. Blue light significantly inhibited the growth of leaf lettuce stems. Adding blue light to white light can shorten internode, reduce leaf area, reduce relative growth rate and improve N/C efficiency. Higher plants need blue light for chlorophyll synthesis and chloroplast formation as well as for high and low chlorophyll a/b ratios. Too much blue light is bad for plant growth. The combination spectrum of red and blue light can promote the growth and development of vegetable seedlings better than red or blue light alone. Different plants need different proportion of red and blue light combination.

3, green light:

Green light and red and blue light can harmoniously adjust to the growth and development of plants. Generally, under the combination of red and blue LED light, the plants are slightly purplish gray, which makes it difficult to diagnose the symptoms of diseases and disorders, and can be solved by adding a small amount of green light. Green light effect is usually opposite to red and blue light effect, for example, green light can reverse stomatal opening promoted by blue light. The photosynthetic yield of the upper chloroplasts near the light surface was lower than that of the lower chloroplasts under strong white light. Because green light penetrates through the leaves better than red and blue light under strong white light, the lower chloroplasts absorb additional green light to a greater extent than additional red and blue light. Green light is not considered for cultivation plants with low light intensity, and green light is not considered for facility plants with low density and low canopy thickness. Green light must be considered for high light intensity and high density and high canopy thickness.

4. Yellow and orange light

Yellow, orange, green and purple light are important photosynthetic effective radiation, but plants need less of them. Adding yellow light on the basis of red and blue light can significantly improve the growth of spinach seedlings. Yellow light is the best to improve the nutritional quality of leaf lettuce, but blue light is more conducive to significantly increase the content of mineral elements of lettuce. The addition of yellow and purple light can improve the photosynthetic ability of cherry tomato seedlings and relieve the red and blue light stress. Compared with white light, violet and blue light increased the activity of antioxidant enzymes and delayed the aging of plants, while red, green and yellow light inhibited the activity of antioxidant enzymes and accelerated the aging process of plants.

5. Far red light

Although the far-red light of 730nm has little significance for photosynthesis, its intensity and ratio to the red light of 660nm play an important role in morphogenesis such as plant height and internode length of crops. Plant morphology and height were controlled by light quality regulation, R/FR ratio. When the ratio increases, the spacing between stems and nodes decreases, the plants dwarf, and the propagating plants tend to elongate. Moreover, the ratio changes have different effects on axillary bud differentiation, chlorophyll content, stomatal index and leaf area. The selective absorption of red light by plants and the selective transmission of far red light make the plants under shade in a light environment rich in far infrared.

6. Ultraviolet (UV)

Wavelengths smaller than 380nm are called ultraviolet. According to the physical and biological characteristics of UV, the wavelength of 320~380nm is uv-a, the wavelength of 280~320nm is uv-b, and the wavelength of 100~280nm is uv-c. 95% of the UV species that reach the ground are uv-a. Photosynthetic active radiation (photosynthetic active radiation), UV and far-red light in sunlight spectrum have regulatory functions on plant growth and development. Ultraviolet radiation reduces plant leaf area, inhibits hypocotyl elongation, reduces photosynthesis and productivity, and makes plants vulnerable to pathogen attack, but can induce flavonoid synthesis and defense mechanism. Low uv-b radiation causes plant growth and hinders the synthesis of plant pigment, which is not easy to cover fruits and vegetables. An important feature of plant factories is the lack of uv-a and uv-b radiation in sunlight. The complete absence of UV radiation will bring negative production effects and affect plant growth and development. Therefore, it is very necessary to regulate the UV radiation level in plant factories.