Planting season is upon us, and it is important for growers
to brush up on early-season growth in corn. The first step is to get good
In order for corn seeds to germinate successfully, there are
three basic requirements: optimum temperature, adequate moisture and sufficient
oxygen. Variations in temperature and moisture can create uneven timing of
germination as well as uneven emergence.
The seed provides energy for the plant for the first few
weeks of life and absorbs about 30 percent of its own weight in moisture during
the germination process.
Enzymes also play a key role during this time. These enzymes
convert sugars, starches and proteins into structural materials for the small
The minimum soil temperature for these enzymes and for
germination is 50 degrees, making optimum temperatures a must.
If all the basic requirements are met, the first structure
to emerge from the seed is the radicle or root, followed by the coleoptile. The
coleoptile is a sheath that helps protect the first leaves.
Next, the seminal roots will grow directly from the seed. A
special stem called the mesocotyl pushes the coleoptile upward.
Near the soil surface, exposure to light causes the
mesocotyl and coleoptile elongation to cease. The coleoptile ruptures, and the
first leaves of the corn seedling emerge.
The mesocotyl not only helps move the coleoptile upward, but
is the structure that allows water and nutrient movement from the seed to the
Damage to either the seed or the mesocotyl can reduce the
survival of the seedling. This structure should remain firm, white and healthy
for several weeks after emergence.
For corn to successfully germinate, the plants need optimum
temperatures, adequate moisture and sufficient oxygen. Once germination has
occurred, a healthy seed, primary root system and mesocotyl are absolutely
essential to drive early-season development.