The significance of light to plants

Light is one of the most important environmental factors for plant growth and development. The wavelength of 43% ~ 52.5% of sunlight reaching the ground is 400 ~ 700nm, which is the visible light that can be seen by human eyes. This is the photosynthetic energy and environmental signal, which affects the growth, development, yield and quality of plants through photosynthesis and light morphogenesis.

First, photosynthesis is the basis for the formation of plant biomass and yield. 95% of plant dry matter comes from carbohydrates produced by photosynthesis. Plants have complex responses to light conditions, including light response, light inhibition, light adaptation, shade avoidance and so on. In the panchromatic spectrum of the sun, only some wavelengths of light are absorbed by plants to produce photosynthesis. Plant leaf morphology, plant physiological response, etc. will affect photosynthesis.

Second, light morphogenesis refers to the process that light acts on plants as an environmental signal to regulate plant growth, differentiation and development. The content of light receptors in plant cells is small, but they are very sensitive to the changes of external light environment. For example, 600 ~ 700nm red light field promotes lettuce seed germination, while 720 ~ 740nm far red light field inhibits lettuce seed germination.