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Plant growth is spectrally selective

The light sources in the existing facility agriculture are difficult to meet the needs of plant growth, thus creating a new market for agricultural lighting. This market is very hot, but for the illumination of agricultural lighting, what should I still not be able to say?
Rather than starting from the environment in which plants grow, most of the plants we see are mostly grown in daylight, so some people think of it. The whole spectrum of daylight simulation gives plants a stable environment for growth. This idea is correct, However, plant growth does not require spectra in all bands.
Plants are selective to the spectrum, and photosynthesis of plants takes about 60% of the light energy in the visible spectrum (380-760 nm), with red-orange light at wavelengths of 610-720 nm (660 nm peak) and 400-510 nm (450nm peak) blue-violet light absorption peak area, these two bands times as the plant's "light". Plants absorb less yellow-green light from 510 to 610 nm. Therefore, the development of these two bands as the main artificial light will improve the plant's light energy efficiency.
Plant growth is selective to the spectrum do you know?
(Experimental method: The acetone extract of chlorophyll is placed between the light source and the prism. After the light is transmitted through the chlorophyll extract and the prism, a visible spectrum is formed at the back and the absorbed spectral region will show a black line or a black band. Right to get the absorption spectrum of chlorophyll.)
As we all know, light is one of the most important environmental factors in plant growth and development. There are two kinds of mechanisms that affect plant growth and yield and quality formation. One is photosynthesis; the other is light form.
First, photosynthesis is the basis for the formation of plant biomass and yield, and 95% of the plant's dry matter is derived from photosynthesis-producing carbohydrates. Plants have complex responses to light conditions, including light response, photoinhibition, light adaptation, and shade avoidance. Only a part of the light in the full-color spectrum of the sun is absorbed by the plants to produce photosynthesis, the leaf shape of the plants and the physiological responses of the plants all affect the photosynthesis.
Second, the formation of light form refers to the role of light as an environmental signal on plants, regulating the process of plant growth, differentiation and development. Light receptor receptors in the plant cells content slightly, but very sensitive to changes in the external light environment. For example, the red field of 600-700 nm promotes the germination of lettuce seeds while the field of 720-340 nm far red light inhibits the germination of lettuce seeds.
Plant growth is selective to the spectrum do you know?
(Plant leaf structure)
Plant growth is selective to the spectrum do you know?
(Plant Cell Structure and Internal Structure of Chloroplast)
Plant growth is selective to the spectrum do you know?
(Photosynthesis in chloroplast diagram)
This requires an additional reference to the concept of "photosynthetic pigments." The leaves are the main organs of plant photosynthesis, and the chloroplast is the most important organelle of photosynthesis. The pigments that absorb light energy in the photosynthesis reaction are called photosynthetic pigments. There are mainly three types of chlorophyll, chlorophyll, carotenoids and algae Cholestin. Higher plants contain the first two categories, and phycobiliphos is found only in algae. One of the best known of chlorophyll. But chlorophyll is not the only pigment useful for photosynthesis. Other pigments are also involved in photosynthesis, so the photosynthesis efficiency can not only consider the absorption spectrum of chlorophyll.
Plant growth is selective to the spectrum do you know?
(Curve 1, bacterial chlorophyll a, curve 2, chlorophyll a, curve 3, chlorophyll b, curve 4, algal bilirubin, curve 5, beta carotenoids.
Plant growth is selective to the spectrum do you know?
(Chlorophyll a effective spectrum)
Plant growth is selective to the spectrum do you know?
(Chlorophyll b effective spectrum)
Plant growth is selective to the spectrum do you know?
(Carotene effective spectrum)
Plant growth is selective to the spectrum do you know?
(Chlorophyll f effective spectrum)
Plant growth is selective to the spectrum do you know?
(Photosynthetic pigment on the spectrum of the specific use Note: from Liu Wenke, Yang Qichang, "LED light source and its facilities, horticultural applications," a book)
Plant growth is selective to the spectrum do you know?
The selective absorption of light waves by different photosynthetic pigments in plants is the adaptation to the ecological environment formed by the plants in the long-term evolution, which enables the plants to utilize various wavelengths of light for photosynthesis.
Photosynthesis is also related to photosynthetically active radiation that impinges on the leaf surface, and photosynthetically available radiation is visible light that is effective for plant photosynthesis. Usually, 8 to 10 photons are needed to complete a photosynthesis. Therefore, the effective photon flux of photosynthesis is evaluated by the photon flux density PPFD (unit: μmol / ㎡ / s), which is in line with the actual photobiological effect. Widely introduced.
Different plants suitable for different proportions of red and blue light at different stages of growth suitable lighting formula is different. The traditional light source of the spectrum can not be controlled, and the LED can emit the monochromatic light needed for plant growth, monochromatic light combination can form the photosynthesis and morphological needs of the spectrum. However, to achieve the regulation of light radiation environment also need to accurately measure the optical parameters of the light environment to meet the growth needs of the corresponding plant.
It is worth mentioning that the most sensitive human eye spectrum is 555nm, between the yellow-green light, the sensitivity of the blue and red regions less sensitive. As mentioned above, plants are not the most sensitive to red light spectrum, but less sensitive to yellow-green light, but the difference in sensitivity is not so great as human eyes. In other words, plants and human eyes respond differently to the spectrum.
Plant growth is selective to the spectrum do you know?
(Ideal light quantum sensor and typical plant spectral response curve)
The spectral characteristics of the PLA-20 plant lighting special analyzer are consistent with the spectral response characteristics of plants, and can accurately determine the absorption spectrum, red / blue light ratio and PPFD parameters of photosynthetic pigments. Can be widely used in plant plants, soilless culture, greenhouse, plant growth boxes and other plant growth in the optical radiation on-site monitoring.
Plant growth is selective to the spectrum do you know?
Plant growth is selective to the spectrum do you know?
 
(PLA-20 plant lighting dedicated analyzer measurable parameters, the red part of its dedicated plant lighting set parameters)
Main Specifications
Wavelength range: 380nm ~ 800nm
Wavelength accuracy: ± 0.5nm
Illumination measurement range: 10lx ~ 200klx
Illumination accuracy: ± 4%
Plant growth is selective to the spectrum do you know?
Plant growth is selective to the spectrum do you know?
Spectral measurement of a plant light
 
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