In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. However, this is not always the case, a root can also be aerial (growing above the ground) or aerating (growing up above the ground or especially above water). Furthermore, a stem normally occurring below ground is not exceptional either (see rhizome). So, it is better to define root as a part of a plant body that bears no leaves, and therefore also lacks nodes. There are also important internal structural differences between stems and roots.
The first root that comes from a plant is called the radicle. The four major functions of roots are 1) absorption of water and inorganic nutrients, 2) anchoring of the plant body to the ground, and supporting it, 3) storage of food and nutrients, 4) vegetative reproduction. In response to the concentration of nutrients, roots also synthesise cytokinin, which acts as a signal as to how fast the shoots can grow. Roots often function in storage of food and nutrients. The roots of most vascular plant species enter into symbiosis with certain fungi to form mycorrhizas, and a large range of other organisms including bacteria also closely associate with roots.
Famous quotes containing the word root:
“And a man of tan engages
For the springtime of her pride,
Eats the green by easy stages,
Nibbles at the root beneath
With intimidating teeth.”
—Gwendolyn Brooks (b. 1917)
“The lack of money is the root of all evil.”
—Mark Twain [Samuel Langhorne Clemens] (18351910)
“But a cultivated man becomes ashamed of his property, out of new respect for his nature. Especially he hates what he has if he see that it is accidental,came to him by inheritance, or gift, or crime; then he feels that it is not having; it does not belong to him, has no root in him and merely lies there because no revolution or no robber takes it away.”
—Ralph Waldo Emerson (18031882)