ROOT SYSTEM (ROOT)                                   Modifications of Root
The root is underground part of the plant and        Roots are modified for support, storage of
develops from elongation of radicle of the           food, respiration.
                                                     1. For support : Prop roots in banyan
Function of root                                          tree, stilt roots in maize and sugarcane.
                                                     2. For respiration: pneumatophores in
  Absorption of water and mineral from soil              Rhizophora (Mangrove).
  Anchorage of the plant body                       3. For storage of food: Fusiform (radish),
  Storing reserve food material.                         Napiform (turnip), Conical (carrot).
  Synthesis of plant growth regulators.
                                                     SHOOT SYSTEM (STEM)
Various types of root
                                                         Stem is the aerial part of the plant and
Tap root                                                  develops from plumule of the embryo.
                                                         It bears nodes and internodes.
  Originated from the radicle.                          Bears bud, may be axillary or terminal
  Persistent in dicot plant. E.g. gram, pea ,           Main function is to spreading branches
   mango                                                  bearing leaves, flower and fruits.
Fibrous root                                         Types of Stem
  Originates from the base of the stem.             There are three types of stem: Underground
  Large number of roots replaces the                stem, Aerial stem and Sub- aerial stem.
   primary root.
  This type of root found in monocot plant.         Underground stem
   E.g. wheat, paddy, grass.
                                                     Stems of some plants remain in the ground and
Adventitious root                                    serve the function of perennation and storage
                                                     of food. They produce aerial shoots annually.
  Roots developed from any part of the plant        They resemble roots superficially but are
   other than radicle.                               distinguishable by the presence of scale leaves
  Found in grass, Monstera and the banyan           and buds at nodes. Such stem also act as a
   tree.                                             means of vegetative propagation. The
                                                     modified underground stems are the following
Regions of root
                                                     Tuber : e.g. Potato
1. Root Cap : The root is covered at the
   apex by the thimble-like structure which          Rhizome : e.g. Ginger
   protects the tender apical part.                  Corm : e.g. Saffron
2. Region of meristematic activity : Cells
   of this region have the capability to divide.     Bulb : e.g. Onion
   The cells of this region are very small,          Sub – aerial stems
   thin-walled and with dense protoplasm.
3. Region of elongation : Cells of this              Lower buds of the stem in some plants grow
                                                     out into short, lateral branches. These are
   region are elongated and enlarged.
                                                     named according to their origin, nature and
4. Region of Maturation : This region has
   differentiated into matured cells. Some of        mode of reproduction.
   the epidermal cells of this region form           Runner : e.g. Doob grass
   thread-like root hairs, which absorbs water
                                                     Stolon : e.g. Jasmine
   and minerals from the soil.
                                                     Offset : e.g. Pistia
                                                     Sucker : e.g. Mentha