Corn seed’s ability to rapidly grow new cells for shoots and roots after imbibing water deteriorates eventually. Unfortunately, this does not occur at the same rate for each seed within a seed lot or for all seed lots. Genetics, field history during seed production, and handling and environment of seed after harvest all affect the rate of deterioration for each individual seed. Associated with the deterioration is a reduced respiratory rate, consistent with the view that the mitochondria, where cellular respiration occurs, are not functioning properly. This process involves the membranes of mitochondria and probably are the main site of the problem. Each living cell includes multiples of mitochondria, each able to replicate and each able to repair membrane damage. Some of that damage occurred during the swelling from water imbibition. It is not difficult to imagine that as cells deteriorate, fewer mitochondria are able to duplicate. This reduces the total conversion of glucose to the chemical energy form (ATP), needed for the cellular duplication necessary for growth shoots and roots. Differences among the seed in this level of damage results in some being slower than others.
Mitochondria are an interesting part of the story of seed deterioration and cell function in all plants and animals. They are the size of bacteria. They can be seen with a light microscope but the anatomical details only seen with electron microscopes. They are the site of conversion of stored energy glucose to useable ATP energy needed for all other cell functions. More information on mitochondria was reviewed in the corn journal blog on 2/9/2016 http://www.cornjournal.com/corn-journal/mitochondria.
One researcher’s personal experience with mitochondria research as it applies to humans is described at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4137050. It is interesting and appropriate that this person grew up on a farm, where curiosity in biology can draw one deeper into trying to understand its basic dynamics.
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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.