From nodal bud to corn ear.
The stems of most vascular plant species have specialized cells at the base of where leaves are attached. These nodes often also have a bud with its own meristem. Genetics and environment determine the development of stem tissue from those nodal buds. Thousands of years of human selection towards specialized expansion of buds to producing only one or two buds into special branch convenient to produce grain and harvest.
Those specific meristems are activated as a short stem with several nodes are attached to short leaves. Then the enclosed stem produces several hundred flowers. Each flower in modern hybrid grain corn, has only the female parts as corn in these flowers developing from these nodal branches. Each flower consists of an ovule and attached stigmata. The activated meristem at this node produces hormones causing flow of sugars to this activated stem and flower tissue. One corn stigmata (silk) grows from one ovule. The cells within each silk are metabolically active and cell expansion is fueled by energy supplied by photosynthesis in leaves and water pressure supplied through vascular system in the short stem and ultimately leading to the roots. Cellular growth extends the silk about 1-1.5 inches per day for about 10 days as it emerges from the surrounding leaves composing the husk. Exposed tip of each silk cell grows side extensions that promote the capture of pollen.
Silk life is relatively short, the tissue degrading after pollination and extension of the pollen tube to the attached ovule. If unpollinated after several day after exposure the cells die. The nodal bud of a corn plant has been selected to produce very specific function in corn. Genetics and environment influence it ability to carry out that function.
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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.