Green wavelength range
It can be seen from the CIE1931 chromaticity diagram that the wavelength range of green light is 500nm-570nm, which is also subdivided into 492-577nm. The spectral design of the plant lamp is usually: 500-600nm. This range is divided for the convenience of calculation and analysis.
The photon energy of green light is between red light and blue light. Green light has the biggest weighting effect on the human eye. Therefore, we will think that the green light is very bright. However, in plant planting, the role of green light is still under discussion.
- Green light in the photosynthesis of pigments
In the absorption spectrum of the pigment, the green light is absorbed very little, only about 6%, and only the chlorophyll is absorbed; then, does the plant need green light in the end? How much do you need? The current research conclusions require the reader to judge.
We see that green plants are green. According to optical theory, green plants reflect green light, and other components of light are absorbed. Then, some people may ask if purple cabbage absorbs green light and red maple leaves are not. Absorbing green and blue light, the answer is yes. We see black objects because black objects absorb all the light. This is the visual conclusion drawn from the basic optical theory, except for color blindness.
2.The evolution of green plants
So, does green light have any effect on planting? We only showcase the case, one who is engaged in technical work, the most important is the instinct of cognitive savvy, and the savvy of technology is innovation.
Life was born in the ocean between 3.8 and 3.4 billion years ago. The original living body is called a chemical synthetic bacterium. The energy used in the chemical reaction of molecules and atoms comes from sulfur-oxidizing bacteria. It does not use sunlight, and plants evolve into green. One of the hypotheses is that other creatures give green light to the plants and co-evolve together. Otherwise, the world has no main color, and most animals can feel the green light, the green light reflected by the plants, and construct the life. The harmony of evolution.
However, the biggest component of sunlight reaching the ground is green light. Why don’t plants use green light?
The reason is that in the process of evolution, the plant is from the ocean to the land. At that time, there was no oxygen in the atmosphere, so the ozone layer was not formed. The short-wavelength ultraviolet light energy was much larger than the present, and the plant chose the energetic sunlight to evolve. Therefore, the photosynthesis bacteria of the oxygen-generating type are known to be dangerous, or develop from the seabed to the land, and chlorophyll, which has completely undergone ultraviolet light energy conversion, is born.
Since then, the plants themselves produce oxygen, and the increase in oxygen in the atmosphere also exacerbates the formation of the ozone layer. The chlorophyll of plants begins to absorb red light that is second only to ultraviolet light and low energy, while green light evolves into plants during plant evolution. The role of the appearance of color, so that other animals can recognize.
Why plants will absorb the energy of green light to absorb the energy of red light. The problem has not been concluded. Plant sensitivity to temperature will also promote the demand for infrared light, and biological evolution follows the most appropriate principles.
The photosynthesis of plants only occurs in chloroplasts. The figure below shows the tissue structure of plant leaves seen from a high power microscope. There are a large number of chloroplasts in the green leaf structure. The chloroplast is a place for photosynthesis in green plant cells. The chloroplast reflects most of the green light. The leaves seen by the human eye are green. It is these chloroplasts that enable the life of the earth to be maintained. The entire earth creature is in the user. Chloroplast photochemical reaction converts solar energy.
Green leaf tissue structure
The theoretical premise of this biological evolution theory is demonstrated by the results of current biological evolution. In any case, at least we know that plants expressing themselves in green make our planet so vibrant.
3. Discussion on the use of green light in plant cultivation
The following case presentations and conclusions are not fully justified and may contain exaggerated ingredients for reference only.
The study of strawberry planting using green light has the following effects:
The pest control effect of the disease, the plant’s resistance is improved.
Fertility promoting effect, moderate stimulation of plants with green light can promote the improvement of strawberry taste.
The quality improvement effect, the strawberry sugar content is high, and the acidity balance is also very good.
Green light has a role in flowering regulation.
b) Some scholars believe that functional ingredients such as vitamin C and polyphenols increase by illuminating green light.
c) Some scholars believe that green light is absorbed. In terms of absorption, the absorption of green light is not large, but the absorption efficiency is equivalent to red light.
d) Some scholars believe that green light has penetrability and internal scattering in the blade. Scattering can be scattered and absorbed multiple times inside the blade, and penetrability can be photosynthesis on the back of the leaf that cannot be reached by red and blue light.
e) Experiments have shown that part of the green light penetrates the plant canopy and provides photosynthesis to the underlying green leaves.
f) The Mokley curve reveals that green light having a wavelength of 550 nm is absorbed the least.
g) An early monochromatic spectral planting experiment conducted by Donghai University, which contains green light planting.
The above data are the conclusions of the planting experiment. The latest data is basically planting experiments with blue light, red light and white light. This shows that the application of green light in plant cultivation basically forms a consensus, only the proportion of green light radiation needs further. the study.
Although green light is needed, the mechanism of green light still has no complete conclusion. The use of LED light source provides a good research method for the research of plant lamp spectrum technology. It has been exploring the application of green light in plant lamp spectrum design in.
4. A question that needs to be answered
Since green light is needed for photosynthesis, why do you use red and blue light to grow vegetables when growing vegetables indoors?
This requires understanding photosynthesis. Photosynthesis only occurs in the chloroplast. It is the process of photon energy decomposing carbon dioxide gas and water molecules under the action of enzymes to form oxygen and glucose. It can be completed with red and blue photons. Green light photons are not needed, but some components of the plant will increase after adding green light, but in the absence of green light, certain components of the plant will be produced according to their own needs and will not affect plant growth.
Plants are evolutionary creatures that have the function of self-regulation and adaptation to the environment. They can obtain the nutrients they need through other channels. Just like people living on the grassland, the amount of vegetables consumed is small, but the same vegetables can be obtained by eating herbivores. nutrition. In planting of artificial environment, the most important thing to consider is the energy consumption index, which is to improve the planting efficiency. The purpose of improving the light quality of the spectrum is to improve the planting efficiency. The development of artificial light source to LED is also the result of the improvement of energy utilization efficiency. Whether the plant light requires a green light component requires a planting process to determine.