Fibrous roots are the type of roots that arise from the base of a stem or the nodes of a horizontal stem (like grasses).
Fibrous roots are present in the monocotyledonous plants.
Similar to a taproot system, fibrous roots also begin as a single main root. These primary roots are short-lived and, therefore, as the plant develops, these roots are replaced by a large number of fibre-like roots arising from the base of the stem. Fibrous roots spread in the soil like a mat; for example, roots of Palm trees.
The roots in the fibrous root system are morphologically similar in contrast to the roots in the taproot system in which a thin, short root arises from a single, thick root.
In this lesson, we are going to discuss the different modifications of the fibrous root system and how they are beneficial for the plants along with appropriate examples. In the end, we will know about some of the major functions of these Fibrous Roots.
Types of Fibrous Root System
1.Fleshy Fibrous Roots
Just like the storage roots of the taproot system, the fleshy roots of fibrous root system also accumulate food and become fleshy and swollen.
The cells of the fibrous root system are modified in such a way that they can accumulate the food prepared by the plants and store it. Once the food is packed, these cells swell and, ultimately, the whole root appears swollen.
The stored food is later utilized by the plants as a source of nutrition during the unfavourable conditions.
The fleshy root system is further divided into three types, that is,
- Tuberous Roots
- Fasiculated Roots
- Annulated Roots
a. Tuberous Roots or Single Root Tubers
These roots occur singly and give the appearance of a taproot.
These swollen roots do not attain any particular shape. Tuberous roots or storage roots are enlarged lateral roots. The cells of these roots are modified in such a way that they can store food inside them.
- Sweet Potato (Ipomoea batatas)
b. Fasciculated Roots
These are the tuberous roots which are present in clusters.
Similar to the tuberous roots, the cells of the fasciculated roots are modified in such a way that they can store food inside them.
Therefore, the only difference between tuberous roots and fasciculated roots is that the tuberous roots appear singly but fasciculated roots appear in clusters.
- Asparagus (Asparagus officinalis)
c. Annulated Roots
These are the swollen roots that possess ring-like structures all over the surface. It appears like discs placed one above the other. Therefore, they are referred to as annulated.
- Ipecac (Cephaelis ipecacuanha)
These roots are short but thick and arise from the basal node of the stem. They grow downward in an oblique direction and penetrate the soil. Once they are rooted in the soil, they develop fibrous roots which hold the soil firmly to support the long and narrow unbranched stem, analogous to the ropes holding a pole or tent.
These roots allow better absorption of mineral salt and water.
- Sugarcane (Saccharum officinarum), Maize (Zea mays), Pennisetum and Sorghum (Sorghum bicolor)– their stilt roots grow in whorls.
- Screwpine (Pandanus odoratissimus)– their stilt roots arise from the lower surface of the oblique stem and provides support.
These fibrous roots are fleshy and form buds. These buds grow into new plants under favourable conditions. Therefore, roots containing buds which help in the formation of a whole new plant are known as reproductive roots.
- Sweet potato (Ipomoea batatas)
Functions of Fibrous Roots System
- They absorb water and dissolved mineral from the soil.
- They can store food in the form of reserve material.
- They can also synthesise growth regulators.
- They keep the plant attached to the soil firmly, that is, provide anchorage.