Plant lighting knowledge: 5 kinds of monochromatic light affecting plant growth
Light is the basic environmental factor for plant growth and development. It is not only a basic energy source for photosynthesis but also an important regulator of plant growth and development. The growth and development of plants are not only restricted by the amount of light or light intensity (photon flux density, PFD), but also by the effects of light quality, namely different wavelengths of light and radiation, and their different compositional proportions. The
The solar spectrum can be roughly classified into ultra violet (UV<400 nm, including UV-A320-400 nm; UV-B280-320 nm; UV-C<280 nm, 100-280 nm), visible light, or photosynthetically active radiation (PAR, 400 to 700nm, among which 400-500nm blue light; 500-600nm green light; 600-700nm red light) and infrared radiation (700-800nm). Due to the absorption of ozone in the stratosphere (stratosphere), UV-C and most of the UV-B cannot reach the surface of the earth. The intensity of UV-B radiation reaching the ground varies depending on the geographical (altitude and latitude), time (daytime, seasonal change), weather (clouds, thickness, etc.) and other environmental factors such as atmospheric pollution ,
1.Red light (R) inhibits internode elongation, promotes lateral branching and delivery, delays flower differentiation, and increases anthocyanins, chlorophyll, and carotenoids. ,
2.In general, increasing the fraction of blue light in white light can shorten the internode, reduce the leaf area, decrease the relative growth rate, and increase the nitrogen/carbon (N/C) ratio.
3.The dry weight of tomato seedlings grown under white light (red, blue, and green light) was significantly lower than that of seedlings grown under red and blue light.
4.Yellow light inhibits growth. Also, yellow light (peak at 595 nm) inhibits cucumber growth more strongly than green light (peak at 520 nm).
5.Ultraviolet radiation reduces plant leaf area, inhibits hypocotyl elongation, reduces photosynthesis and productivity, makes plants vulnerable to pathogen attack, but can induce flavonoid synthesis and defense mechanisms