The Effects of the Light Spectrum on a Plant

Our sun emits tremendous energy in the form of wavelengths, including visible light. X-rays, ultraviolet rays and infrared rays are showered upon the earth, and the atmosphere helps shield the life on earth from the harmful rays. Plants convert solar energy into basic foods like sugars and starches. While visible light is present, there remains ultraviolet and infrared light wavelengths that can effect plant and animal life, too.

Engine for Photosynthesis

Bend visible light with a prism and the full gamut of colorful wavelengths are revealed, just as in a rainbow after a thundershower. Pigments in plant leaves absorb visible light, propelling the making of food--the process known as photosynthesis. Not all light colors are utilized by plants. According to graphs supplied by the Estrella Mountain Community College, the many different pigments in leaves most readily utilize visible light that is in the violet, blue and red color wavelengths.

Damage of Cell DNA

Ultraviolet light (UV) has very high frequency in its wavelengths. Earth's atmosphere filters some UV radiation, and plant pigments also absorb various levels of these rays. Excessive exposure to UV rays can destroy individual plant cells as well as the DNA (genetic materials) in the cell nucleus. While natural sunlight typically doesn't harm plants, manipulation of UV light exposure on plants in a lab setting by humans can visibly create genetic mutations. An example of a mutation caused by UV overexposure is the modification of leaf pigmentation, so that a normally green leaf may develop with variegation with white or pink hues.

Heat Build-Up

Infrared light energy is most often equated with microwaves and heat. Plant foliage absorbs infrared light without harm, as the excessive build-up of heat is off-set by transpiration by the leaves. Transpiration allows water molecules from the plant to escape through pores called stomata and effectively cool the temperatures on and in the leaf tissues. If soil moisture is lacking and not enough water pressure exists in the plant, heat from infrared light energy can cause wilting. Severe cases cause death of tissues and death of a plant.

Keywords: plants and sunlight, effects of light, light wavelengths, visible light spectrum

About this Author

James Burghardt has written for "The Public Garden," "Docent Educator," nonprofit newsletters and for horticultural databases, becoming a full-time writer in 2008. He's gardened and worked professionally at public and private gardens in Colorado, Florida, Minnesota, New York, North Carolina and Pennsylvania. He has written articles for eHow and GardenGuides.