What is the meaning of light for plants?
Light is one of the most important environmental factors for plant growth and development. Sunshine to reach the ground 43% to 52.5% wavelength of 400 ~ 700nm, is visible to the human eye visible light, which is photosynthetic energy and environmental signals, through photosynthesis and light form of the pathways affect the growth and development of plants and yield quality The
First, photosynthesis is the basis of plant biomass and yield formation, 95% of the plant dry matter from the photosynthesis of carbohydrates. Plants have complex reactions to light conditions, including light response, light suppression, light adaptation, and so on. Only part of the spectrum of the sun's light is absorbed by the plant to produce photosynthesis, plant leaf morphology, plant physiological response, and so will affect photosynthesis.
Second, the light form is built as light as an environmental signal on the role of plants, regulating plant growth, differentiation and development process. The receptors that experience light are less in plant cells, but are sensitive to changes in the amount of ambient light. For example, 600 ~ 700nm red field to promote the germination of lettuce seeds, and 720 ~ 740nm far red areas inhibit lettuce seed germination.
2 What is "light fertilizer"?
Plants use photosynthesis at different wavelengths, that is to say, plants have a selectivity to the spectrum. The photosynthesis of plants is about 6% of the light energy absorbed in the visible spectrum (380 ~ 760nm), with wavelengths of 610 ~ 720nm (Peak 660nm) of red and orange light and 400 ~ 510nm (peak 450nm) blue violet light absorption peak area, the two bands to become the plant "light fertilizer."
LED can produce the monochromatic light needed by plant growth, monochromatic light combination can form plant photosynthesis and form the required spectrum. LED plant growth light source can improve the plant's light energy utilization.
3 What is the effect of the photosynthetic apparatus?
Light and institutions are broadly said to be able to carry out part of the reaction or all the reaction of photosynthesis, small to chloroplast, thylakoid, large mesophyll cells, leaf organs, so that the entire plant. Narrow is the chloroplast.
First, photosynthetic institutions affected by light adversity. Too strong and weak light will lead to plant light adversity, inhibition of photosynthesis, reduce photosynthetic efficiency. Weak light causes the phenomenon of yellowing occurs, under the light of plants produce reactive oxygen free radicals, resulting in light suppression.
Second, the photosynthetic mechanism is affected by temperature. The cyclical changes in temperature affect plant photosynthetic carbon fixation, reduction, sucrose synthesis, photosynthetic product transport and distribution and electron transport.
Third, photosynthetic organs are affected by nutrient supply. Nitrogen nutrition is the life basis of plants. The correlation coefficient between leaf photosynthetic capacity and nitrogen content was 0.9, and the photosynthetic rate of light was increased linearly with the increase of nitrogen content. Therefore, maintaining nitrogen nutrition and other related elements related to chlorophyll anabolism is important to protect the activity of photosynthetic apparatus.
Fourth, photosynthetic institutions are affected by carbon dioxide. Carbon dioxide is the main raw material of photosynthesis. The increase of carbon dioxide concentration in the air at the saturation point can improve the plant photosynthetic rate, reduce transpiration, inhibit plant respiration and improve the plant water use efficiency. Keeping the appropriate concentration of carbon dioxide is critical to the promotion of carbon dioxide.
Fifth, the photosynthetic mechanism by the humidity wind speed and so on. The low stomatal conductance or too high air relative humidity will reduce the stomatal conductance of plant leaves, increase the carbon dioxide into the leaf resistance, reduce the transpiration rate, especially in the low water and fertilizer supply conditions, easily lead to plant water nutrient deficiency, The effect of carbon dioxide. The wind speed will affect the uniform distribution of carbon dioxide in the plant canopy and the community, affecting the effect of increasing carbon dioxide. In the case of sufficient water supply, high concentrations of carbon dioxide increase the stomatal conductance of soybean leaves and reduce the amount of water evaporation.