Young corn seedlings are provided with energy for growth and development by new photosynthesis in the young leaves. Light, of course is the important, source of that energy as a series of enzymes in the chloroplasts transform the light energy into stored chemical energy of glucose. Glucose is moved to mitochondria in cells, where the energy is captured into the chemically useable energy of ATP. This chemical energy powers the growing points as it divides, resulting in more cells including more chloroplasts and mitochondria. The result is a growing corn plant.
The other, perhaps less obvious energy source is heat. The speed of movement of the process in all aspects of the plant cells is affected by heat energy. This includes the rate of photosynthesis, the rate slowing as temperatures approach freezing and increases until temperatures above 104°F, at which enzyme integrity falls apart. Low temperatures also slow down the movement of the glucose within and to other cells. The low temperature effect on glucose movement appears to be greater than the effect on photosynthesis, resulting an accumulation of sugars in the leaf tissue.
Plants, including corn, tend to react to over accumulation of sugars in leaves, by production of pigments, a form of carotene called xanthophylls. These are often red pigments in corn. They absorb the light energy, protecting the molecules within chloroplasts from damage from accumulation of too much glucose.
Hybrids will vary in intensity of red pigments in plants that are exposed to cold spring weather but, they will recover with warm weather as glucose resumes movement to the growth areas.
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.