Emerging corn seedlings initially utilize the primary root for absorption of water and nutrients as this root tissue is powered initially by the endosperm and then the photosynthesis from the first seedling leaves. Initial stem nodes remain under the soil surface. Soil temperatures affect the growth rate of the seedling but by time the third leaf is visible inside the whorl of the seedling, lateral secondary roots emerge from the nodes below the soil surface. Photosynthate are moved to these root tips stimulating more cell in new root tips as hormones direct the growth down. Cells outside the dividing root tip cells develop a strong epidermis allowing the root to push through the soil.
Newly formed cells of the elongating roots, near the root tip includes epidermal cells with thin-walled protrusions called root hairs. These protrusions into the soil affectively expand the net root surface area of the root allowing flow of water and nutrients into the root by osmosis.
Cells in the core of the new root differentiate to form vascular tissue that connects to the stem vascular tissue through the nodes. This vascular tissue allows transport of water and minerals upwards through the xylem and carbs downwards through the phloem. A few cells in this vascular portion of the young root maintain cell division capability, becoming stimulated by another group of hormones (cytokinins) to increase cells laterally, pushing through the epidermal cell layer becoming lateral roots with their own root meristems. As more lateral root branches form, along with their root hairs the water and nutrients shipped to the developing seedling leaves the upper leaves are formed and photosynthesis increased.
This early coordination of shoot and radical root emergence from the seed. Initially with energy from the seed endosperm and then from photosynthesis, allows the new plant to develop for its annual lifetime.
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.