Red corn plants

​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.