Increasing the level of nutrients in plants by irradiating with visible light

摘要

The level of phytochemicals in a plant cell comprising chlorophyll or in a plant tissue comprising chlorophyll can be altered by irradiating the plant material with light of at least one wavelength selected from the range 400nm to 700nm. Preferably, a source of red light of wavelength 600nm to 700nm is used in combination with a source of blue light of wavelength 420nm to 490nm. In examples, the ascorbate and glutathione levels of harvested bokchoi, broccoli and spinach were increased by exposure to visible light. The plants may be exposed to visible light within an exposure chamber 11 having a glass plate 12 for supporting the plant material. A plurality of light sources 14 and reflectors 16 expose the plant material to light from several directions. A programmable timer 17 and switching means control the length of time the plant material is exposed to the light.