Individual plants in corn fields are starting to show red leaves as the season approaches the final days of grain fill. Close observation of these plants reveals that they have very few kernels, generally because of poor fertilization. These plants probably were silking only after most pollen in the field was gone, perhaps because of late emerging seedlings or other causes of late silk emergence such as moisture stress.
Red pigments are caused by production of a flavonoid known as anthocyanin. Many plant species produce anthocyanins, especially in reaction to stresses such as low temperatures, diseases or insect damage. Anthocyanin compounds accumulate in cells as water soluble compounds in cell vacuoles. It is derived from glucose in a synthesis and is linked to accumulation of glucose within the cells. It has the effect of absorbing light with effect of reducing photosynthesis.
It is not completely clear the advantage to the corn plant to reduce glucose production by absorbing less light for photosynthesis. Perhaps it reduces the callose development in phloem tissue that could reduce the flow of glucose to the few developing kernels. It is clear that it is related to accumulation of glucose in the leaf tissue because of reduction of transport to grain.
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.