Root system

Root system

                 The portion of the plant body present below the soil is called root system. In dicots, the taproot system is present, whereas in monocots fibrous root system is present 

Functions

          The root system fixes the plant in the soil and the root hairs absorbs water and minerals salts. The different regions of the root and their function are:

1. Region of root cap: It covers the apex of the root 

2. Region of cell division: The cells undergo repeated divisions.

3. Region of elongation: Increase of growth in length takes place.

4. Region of root hair: Absorbs water and mineral salts.

5. Region of maturation: This provide anchorage to the plant ( helps in fixing plant body ).

            Now let us discuss the modifications of root for performing the function of respiration. These roots are called respiratory roots or pneumatophores. These roots are seen in plants growing in marshy places and salt lakes. From the underground portion of the roots many conical spikes grow vertically upward around the tree trunk. They are provided with numerous pores or respiratory spaces through which air is taken in for respiration. e.g. Avicennia and Rhizophora. Roots that grow from any part of the plant body other than radicle are called adventitious roots. They are of various kinds and have diverse functions normal and specialized. 

            Those with normal functions may be of the following types.

1. Fibrous roots: Cluster of roots are formed from the lowermost node of the stem. e.g. Sugarcane and Bamboo.

2. Foliar roots: Cluster of roots arise from the petiole of leaf. e.g. Pogostemon. 

3. Adventitious roots: Cluster of roots arise from any part of the plant body. e.g. Bryophyllum (Leaf margin), Coleus (branch cutting). 

           In some plants the adventitious roots are modified to perform some special functions like storage. e.g. Sweet potato, mango ginger.

              In some plants, roots are produced for mechanical support. So let us discuss climbing roots and buttress roots.

1. Climbing roots: These roots are formed at the nodes for fixation. e.g. Betel, Pothos.  

2. Buttress roots: In some large forest trees, stout roots arise at the base of the trunk. They provide support. e.g. silk cotton tree.