Anthocyanin is a flavonoid compound produced in plants and giving color to the tissue. It accumulates in the aleurone layer cells in corn kernels of varieties we commonly call Indian corn. This pigment is water soluble and therefore easily extracted. Although it’s total function in grain is not known, the compound does have some microbial inhibition character and perhaps is part of a pathogen resistance system. Selection for purple corn was incorporated as part of the movement of corn to many parts of north and south hemisphere and remains as a mainstay among certain cultures who use the pigments.
Anthocyanin also is the purple pigment that occurs in seedlings of some corn hybrids when temperatures are low. It is mostly a response to accumulation of sugars in tissue because the low temperatures slow down the movement of the sugars to growing points when under this condition. Phosphorus deficiency can be indicated by the purple leaves for the same reason. This functions to block light absorption by chloroplasts and thereby reducing photosynthesis. Red and purple reactions in corn when sugar transfer is inhibited because of disruption of xylem tissue due to borers, or lack of sufficient developing kernels to draw the sugar from leaves also trigger production of anthocyanin. Again, the function is to reduce light absorption in chloroplasts and therefore reduce photosynthesis and production of more sugar.
Genetics affect the occurrence and color intensity of anthocyanin in corn kernels. Although the major dominant gene is needed for purple corn kernels, the intensity of the color is affected by minor genes in the creation of the anthocyanin molecules.
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About Corn Journal
The purpose of this blog is to share perspectives of the biology of corn, its seed and diseases in a mix of technical and not so technical terms with all who are interested in this major crop. With more technical references to any of the topics easily available on the web with a search of key words, the blog will rarely cite references but will attempt to be accurate. Comments are welcome but will be screened before publishing. Comments and questions directed to the author by emails are encouraged.