Imbibition of water into the seed leads to activation of the cytoplasm within cells. Most of those processes occur along membranous components of mitochondria, ribosomes, plastids and the endoplasmic reticulum. Hydrated proteins now acting as enzymes in break down starch molecules stored in the endosperm and glucose and sucrose molecules are moved thru the scutellum to embryo cells. Diffusion of these sugars through pores of these cells, with cooperation of the cellular membrane and endoplasmic reticulum, these complex molecules composed of carbon, hydrogen and oxygen atoms are transported to mitochondria where they are further metabolized to create the ATP energy needed for other cellular activity. This cellular respiration process allows further cell construction as cells divide in the root and shoot meristems. Elongation of hypocotyl cells, as well as meristem cell division pushes the tissues from the kernel.
Heat energy helps in driving these metabolic activities, including repairing damage to membranes occurring during seed production and storage, as well as those enhanced by hydration of membranes after planting.
ATP (adenosine triphosphate) results from the energy transfer from electrons holding the glucose atoms together to form ATP, releasing CO2 and H2O. This process occurs in the mitochondria. These membrane-intense organelles apparently vary in number and efficiency among corn varieties. Mitochondria, having their own DNA, and yet is dependent upon the rest of the cell for its structural components, are transmitted to the next generation only through the egg cell. This is probably why different female parents of corn hybrids vary in time for seedling emergence and vulnerability to imbibition chilling damage.
It is amazing to see a near-perfect emergence of corn seedlings in a field, given all that had to happen at the cellular level.
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.