Experiment on growing tomato seedlings with plant lights
Phytochrome is distributed in various organs of plants. As a photoreceptor, it can induce and regulate the morphogenesis of plants after absorbing light of different wavelengths, and has a significant impact on certain physiological processes. For example, in the germination of lettuce seeds, phytochrome participates in the release of dormancy and the germination of seeds. In the dry seed state after the seeds mature, there are two types of red light-absorbing (Pr) and far-red light-absorbing (Pfr) containing photosensitizing pigments. Pr absorbs red light and converts to Pfr, and Pfr absorbs far red light and converts to Pr. Pfr is the activated form of phytochrome, which can cause various physiological reactions. When the germination conditions are suitable, Pr will be hydrated and converted into Pfr under the irradiation of light, leading to germination.
Generally speaking, light-sensitive seeds are large-grain seeds. They have enough storage material to maintain the seedlings to grow in the dark underground environment for a long time. Generally, light is not needed for germination, such as melons; while seeds that require light are mostly small seeds. When they are in a soil layer that is impermeable to light, they remain dormant. Only when they are on the soil surface, they rely on a small amount of stored materials to germinate, so as to extend out of the soil surface in time for rapid autotrophic growth. This is ecologically meaningful. If a small seed can germinate in the dark under the soil surface, it will have exhausted its storage material and cannot survive when it can't reach the soil surface.
Plant light scientific research experiment
III. The growth and differentiation process of seedlings.
This impact can be divided into two aspects, direct and indirect. Indirect effects refer to the influence of light on plant growth through photosynthesis, transpiration and material transport. This indirect effect is a high-energy reaction, because light is an energy source for photosynthesis, and insufficient light cannot produce enough organic matter, and plant growth loses its material basis. In addition, light can also affect plant transpiration. Light is the most important external factor affecting transpiration. Most of the solar radiation energy absorbed by leaves is used for transpiration. In addition, light directly affects the opening and closing of the stomata. When the stomata are opened under light, the resistance of the stomata is reduced, and the vapor pressure difference between the inside and outside of the leaf is also increased, which speeds up transpiration and facilitates the transportation of materials. However, if the soil moisture is insufficient, it will cause insufficient plant moisture and affect the growth of plants.
The direct effect of light is as a signal transmission. This process is related to the regulation of phytochrome. For example, in dicotyledonous plants, the hypocotyls break out of the soil and stretch out in front of the ground, and the stem tips are hook-shaped. When they are unearthed, they are irradiated with red light to form Pfr (activated type) to promote the hooks to unfold. In addition, seedlings grown in the dark and seedlings grown in the light are very different in morphology. In the dark, the seedling plants are thin and long, the stems are slender and fragile, the mechanical organization is underdeveloped, the top is hook-shaped, the internodes are very long, the leaves are small and cannot be expanded, there is no chlorophyll, the photosynthesis cannot be carried out, and the root system is poorly developed. This kind of seedling is called chlorophyll because the stems and leaves are yellow. The red light promotes the unfolding of young leaves, inhibits excessive elongation of the stem, and plays the most effective role in eliminating yellowing.
The plant supplement light is to simulate the wavelength band of the sun's visible light wave band 400-780nm which has an impact on plant growth, highlighting the advantages of 455-465nm blue light and 640-700nm red light band, which can promote plant photosynthesis and promote plant photosynthesis in an environment with little or no light. plant growth.
The influence of light on cell growth and differentiation, the inevitability of plant growth lights, the influence of light on cell growth and differentiation, the inevitability of plant growth lights, I. All cells can divide, grow and differentiate. Cell division increases cell number, cell elongation increases cell volume. On the surface, it seems that there is no direct connection with light. But in fact, when the seedlings grow up to a certain degree of photosynthesis, photosynthesis will provide the necessary material and energy for cell division and elongation. The cytoplasm of the dividing cells is strong and the anabolism is strong. It can assimilate inorganic salts and organic matter into the cytoplasm, providing a material basis for cell division; when the cell volume is elongated, the energy required for cell growth is mainly from respiration, but photosynthesis The role also serves as a certain source of energy supply, and photosynthesis is not completely unrelated to cell growth.
II. The influence of light on the differentiation of plant cells may be greater. This is manifested in light-induced, changing cell polarity and so on. Cell polarity is the basis for unequal division of cells, and unequal division or differentiation (that is, the two daughter cells produced by cell division have different morphological, physiological and biochemical properties) are the basis for the polar structural differentiation of plant tissues. Experiments have shown that the zygote produced by the combination of large and small spores of Fucus has no cell wall at the beginning and is a completely apolar spherical cell, but under the irradiation of unidirectional light from top to bottom, within a few hours after the formation of the zygote This forms the polarity characterized by the unidirectional calcium ion flow in the cell. At this time, changing the direction of light irradiation can change the direction of the cell polarity. But after the cell wall is formed, the polarity of the cell is fixed. This shows that before the cell is completely polarized, the light has an effect on the cell polarity, affecting the direction of division and differentiation.
Use plant lights to grow industrial hemp in the greenhouse, use plant lights to grow industrial hemp in the greenhouse, greenhouse cultivation can effectively increase the content of other cannabinoids such as industrial hemp CBD, strictly control the THC content, and ensure its stability.
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Compared with traditional outdoor cultivation, growing artificial hemp in a greenhouse can better control the environment in which hemp grows, including temperature, humidity, light, nutrients, and water. Various environmental factors are the guarantee of the content of various cannabinoids such as industrial hemp CBD.
According to the crop habits and nutrient requirements of industrial hemp, the growth process is regulated to ensure the quality of its growth to the greatest extent. For example, a seed with a CBD content of around 109 can be planted in a greenhouse to fully realize its expected CBD content, and even make a breakthrough. But planting outdoors cannot control light, temperature, humidity, pests and diseases, and other natural disasters, and its cannabinoid content is difficult to achieve. More importantly, indoor cultivation can completely control the THC content in hemp crops.
As we all know, cannabinoids can be converted into each other according to the change of light and light environment. Taking CBD and THC as examples, the two are actually isomers, which are very similar in element composition and molecular structure. After years of planting research, we found that the THC content in hemp plants can be controlled and changed by light.
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