The end of a root is surrounded by a hood of cells called coif, whose function is to protect the root meristem, a tissue in which cells are actively multiplying by mitosis.
It is in the meristem that the new root cells are produced, which enables their growth. Just beyond the extremity is the region where mitosis-grown cells grow. In this region called distention zone or cell stretching, the root has the highest growth rate.
After the distention zone lies the piliferous zone of the root, which is characterized by epidermal cells with thin and elongated cytoplasmic projections, the absorbing hair. It is through these hairs that the root absorbs most of the water and minerals it needs.
Already the region of secondary branches It is the one that notices the sprouting of new roots that arise from internal regions of the main root.
The main function of the root is nutrient absorption in the soil, it is also responsible for the fixation of the vegetable to the substrate. Some root types, however, also perform other functions:
Tuberous Rootslike cassava, sweet potato and turnip store food reservesmainly in the form of starch grains, used during flowering and fruit production by the plant. Farmers harvest these roots before the plant has a chance to consume the stored reserves, using them for human and animal feed.
Respiratory Roots or Pneumatophores are adapted to gas exchange with the environment. This type of root is found in plants such as Tommy Avicenna, which lives on soggy, oxygen-poor soil in the mangroves. The main roots of this plant grow close to the soil surface and, from space to space, have pneumatophores, which grow upward, perpendicular to the soil. During the ebb tide the pneumatophores are exposed and can exchange gases with the air.
Support roots, also called root-struts, increase the grounding base of the plant. Some tree species have tubular roots, shaped like upright planks, which increase plant stability and provide greater breathing surface for the root system.
Aerial roots they are characteristic of epiphyte plants, that is, that live on other plants without parasitizing them. These roots can reach several meters in length before reaching the ground, forming the vines.
Sucking Roots They are adapted to the extraction of food from host plants and are characteristic of parasitic plants, such as lead liana and chickweed. The sucking roots have a fixation organ, called the apprehensive one, from which thin projections called haustories depart. The haustories they penetrate the host plant until they reach the sap-conducting vessels, where they extract water and nutrients that the parasitic plant needs to survive.
If the plant is hemiparasite, as in the case of bird weed (it is chlorophyll, and therefore autotroph), only the raw sap (water and minerals), which travels through the woody vessels of the xylem, is removed from the host plant.