Multiple copies of chlorophyll molecules are located on the folded membranes (thylakoids) within the chloroplasts in corn leaves. The complex structures of these molecules allow the absorption of the blue and red wavelengths of daylight, reflecting the green portion of light that we see in green leaves.
Two major types of chlorophyll molecules are found in corn leaves. Chlorophyll a includes 57 atoms of carbon, 72 atoms of hydrogen, 5 of oxygen, 4 nitrogen and one magnesium. Absorption of a photon of light energy frees up an electron from the chlorophyll a molecule that gets transmitted to chlorophyll b molecules that has only 2 less atoms of hydrogen and one more oxygen atom. This energy ultimately is used to split the water molecule by freeing the hydrogen ion to be combined with carbon dioxide to form glucose. Oxygen molecules are thus freed as a gas and moved through the plant stomates into air.
Construction of the complex components of chlorophyll molecules can occur in the dark but the final step requires light. Seedlings grown in complete darkness are yellow but shortly after exposure to light they become green. Nitrogen or magnesium deficiencies in the plant will affect the chlorophyll construction but also other minor elements such as iron are needed in the biosynthesis process of the enzymes leading to the construction of chlorophyll. Although much of the genetics controlling final construction and function of chlorophyll is within the chloroplast DNA, the chromosomal DNA within the cell nucleus affects the supply of essential chemicals.
Growth of plant tissue needed to supply those chemical components for chlorophyll initially supplied by carbohydrate energy in the seed, becomes dependent on that supplied by chlorophyll as glucose energy is transmitted to mitochondria where the molecules are broken apart supplying the energy in the form of ATP to be used to drive construction of more corn structures. This cycle continues until excess energy is deposited in grain and the plant begins senescence.
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.