The different types of roots are related to their adaptations to the environment to which they are exposed.
Roots are extremely important structures for plants. It is from it that the plant is able to sustain itself and extract water and nutrients from the substrate. Several types of roots are found and vary according to the environment in which each species lives.
In general, we can divide the roots into two large groups: the pivoting and fasciculated roots. Pivoting are those found in eudicots and are characterized by the formation of a main root from which the ramifications depart. These branches are called secondary roots.
Unlike taproots, in fasciculate roots a taproot is not found, as in these plants it is usually short-lived. Fasciculate roots are found mainly in monocots and are formed by a large number of small-diameter roots, which is why they are also called hair. As they are not formed from the radicle region but from the stem portion, these roots are considered adventitious.
Roots can be classified into other more specialized types, taking into account their adaptations. Below are some of these types:
– Support roots: These are very important adventitious aerial roots for the support of plants in soils that are not firm and plants that are very large, but do not have an efficient support base. It is worth noting that they also act by absorbing water and mineral salts. As an example we can mention the roots of corn.
– Tabular roots: It is a type of support root that gets its name because of its appearance of large boards. They act by increasing the support of the plant, in addition to helping with aeration. Type found mainly in large trees such as chichá.
– Respiratory, aeration or pneumatophore roots: These roots are very common in plants that live in mangroves, mainly because they exchange gas with the environment. They have negative geotropism and therefore can be seen coming out of the ground. In them are found structures called pneumatodes, which allow obtaining oxygen. Example: Avicennia schaueriana .
– Sucking or haustoria roots: These roots are found in parasitic and hemiparasitic plant species. They act by taking their food from the plants in which they settle, penetrating projections called haustoria inside the conducting vessels. When the plant is parasitic (eg lead vine), the haustoria will remove water and nutrients by sucking the elaborated sap. When plants are hemiparasites (eg mistletoe), they will not depend on nutrients, as they are capable of carrying out the photosynthesis process. In the latter case, they only remove water and mineral salts from the host plant.
– Strangulator root: These roots are also parasitic, but, unlike haustoria, there is no penetration to remove the sap, only strangling the host species. The plant dies as it is unable to grow due to the strangling roots that envelop its trunk. An example of a plant that has this type of root is the mata-pau.
– Tuberous roots: Roots characterized by thickening due to the large accumulation of reserve substances, mainly carbohydrates, such as starch grains. The reserve normally occurs in the parenchymal tissue. Among the species that have this type of root we can mention cassava and carrots.