The results showed that compared with plants grown under UV stress at low light intensity (PAR100) and low blue light quantity (30%), under UV stress, whether under higher light intensity (PAR300) or high blue light quantity (62%) Plants show better photosynthetic capacity (higher photosynthetic rate, maximum photochemical efficiency (Fv/Fm) and lower non-photochemical quenching (NPQ).
The chlorophyll content and carotenoid content of plants grown under the treatment of low light intensity (PAR100) and low blue light quantity (30%) under UV stress were significantly reduced due to UV. On the contrary, plants under higher light intensity or under high blue light amount accumulated more epidermal flavonols. Similar to the high PAR effect, the results indicate that the high blue light ratio initiates special biochemical and physiological processes, promoting better adaptation and recovery from UV stress damage.
An important feature of plant factories is the lack of UV-A and UV-B radiation in sunlight. The biological effects of facility horticultural crops under the condition of UV deficiency are unclear, but with the destruction of the ozone layer, the UV-B intensity of solar radiation increases, facilities The changes in internal UV and its biological effects are currently less clear.
On the one hand, the plant factory covering material protects the facility plants from the harm of UV radiation, but the complete lack of UV radiation also brings negative production effects. Therefore, it is very necessary to regulate the UV radiation level in the plant factory, but this regulation must be based on the production demand and the plant tolerance response law.
B radiation often causes problems such as lengthy plants of facility vegetables, low nutritional quality, dull color, and unfresh taste. It also hinders the synthesis of plant pigments and is not conducive to the production of solanaceous vegetables. A reasonable dose of UV-B radiation can dwarf plants, promote the accumulation of secondary metabolites such as carotenoids, and improve tomato fruit quality. However, high-dose UV-B exposure can also trigger some responses to plant photosynthesis, such as CO2 absorption, photosynthetic electron transport chain, dark respiration, stomatal behavior, pigment content and plant endogenous hormone content, which inhibit plant growth and development. UV-A also affects the growth and development of plants, but the biological effects are small.
In order to solve these problems in the cultivation of vegetables, the use of artificially controlled UV-B light sources to supplement UV-B radiation in the facility can achieve good results in improving the quality of these vegetables. In addition, fluorescent lamps and light-emitting diode lamps are used to cultivate vegetables under artificial light, and the quality control problem must rely on supplementing UV-A and UV-B.
The regulating effect of UV on the quality of facility plants
​Hoffmann et al. (2015) found that PAR intensity plays an important role in the adaptation of plants to UV radiation. Therefore, the special morphological and physiological characteristics affected by strong light are also affected by blue light. The author believes that a larger amount of blue light in the spectrum is beneficial to the ability of plants to adapt and recover under UV radiation.
The results showed that compared with plants grown under UV stress at low light intensity (PAR100) and low blue light quantity (30%), under UV stress, whether under higher light intensity (PAR300) or high blue light quantity (62%) Plants show better photosynthetic capacity (higher photosynthetic rate, maximum photochemical efficiency (Fv/Fm) and lower non-photochemical quenching (NPQ).
The chlorophyll content and carotenoid content of plants grown under the treatment of low light intensity (PAR100) and low blue light quantity (30%) under UV stress were significantly reduced due to UV. On the contrary, plants under higher light intensity or under high blue light amount accumulated more epidermal flavonols. Similar to the high PAR effect, the results indicate that the high blue light ratio initiates special biochemical and physiological processes, promoting better adaptation and recovery from UV stress damage.
An important feature of plant factories is the lack of UV-A and UV-B radiation in sunlight. The biological effects of facility horticultural crops under the condition of UV deficiency are unclear, but with the destruction of the ozone layer, the UV-B intensity of solar radiation increases, facilities The changes in internal UV and its biological effects are currently less clear.
On the one hand, the plant factory covering material protects the facility plants from the harm of UV radiation, but the complete lack of UV radiation also brings negative production effects. Therefore, it is very necessary to regulate the UV radiation level in the plant factory, but this regulation must be based on the production demand and the plant tolerance response law.
B radiation often causes problems such as lengthy plants of facility vegetables, low nutritional quality, dull color, and unfresh taste. It also hinders the synthesis of plant pigments and is not conducive to the production of solanaceous vegetables. A reasonable dose of UV-B radiation can dwarf plants, promote the accumulation of secondary metabolites such as carotenoids, and improve tomato fruit quality. However, high-dose UV-B exposure can also trigger some responses to plant photosynthesis, such as CO2 absorption, photosynthetic electron transport chain, dark respiration, stomatal behavior, pigment content and plant endogenous hormone content, which inhibit plant growth and development. UV-A also affects the growth and development of plants, but the biological effects are small.
In order to solve these problems in the cultivation of vegetables, the use of artificially controlled UV-B light sources to supplement UV-B radiation in the facility can achieve good results in improving the quality of these vegetables. In addition, fluorescent lamps and light-emitting diode lamps are used to cultivate vegetables under artificial light, and the quality control problem must rely on supplementing UV-A and UV-B.