Corn fields in northern Illinois are close to peaking in growth, with tassels showing beginning to emerge. It is remarkable that these field showed only small seedlings a few months ago. We are observing the result of light energy being transformed into chemical energy in the chloroplasts within leaf cells. That energy bonding carbon dioxide molecules to hydrogen atoms derived from water molecules formed glucose, some of which was moved to mitochondria within the cells. Respiration in the mitochondria transformed the bonding energy within glucose to form ATP molecules as an energy source for other cellular activity and growth. New cells, originating from the cell division at growing points, elongated due to turgor pressure caused by movement of water molecules and osmosis.
Glucose molecules eventually were chemically hooked together as specific enzymes changed their structures, causing hydrogen bonding to be shared by the molecules. Hundreds of them formed a solid wall of cellulose surrounding the cells. Cellulose is the most common polysaccharide in cell walls but other modifications of the linking the carbon, hydrogen and oxygen atoms form other strengthening compounds such as hemicellulose, lignin and pectin. The ratio of these molecules varies among tissues affecting their function. Each varies in ultimate strength and digestibility. All contribute to the rapid growth that we witness in a corn plant at this time of the season.
Each step of synthesis, beginning with photosynthesis, is dependent upon specific enzymes and energy. Enzymes are proteins, strings of amino acids attached in the ribosomes of cells. Twenty amino acids have been identified, based on their arrangement of hydrogen, carbon, oxygen and nitrogen atoms. The arrangement is dictated by the DNA code of the cell nucleus. Each of the 4 nucleic acids in the chromosome, when transcribed into RNA at the appropriate time, is carried to the ribosome where the appropriate amino acid is attached to the next one according to the arrangement of the code. That arrangement of amino acids affects the specific enzymatic action of the protein participating in synthetic reactions within cells, including formation of cellulose chains.
That rapid growth of corn plants is the result of external factors such as light, water and fertilizer but it is also interactions within each cell as influenced by the genetics. One summary of cellulose synthesis and regulation can be found on this online publication by the American Society of Plant Biologists https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3894906/
Visit us at the ASTA in Chicago, Dec 9-12 (booth G207)
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.