Roots- Morphology of Flowering plants

The term Morphology derived from Greek words: morphe– forms and logos– study

Morphology is the branch of biological science that deals with the study of the form, size, shape, color, and external structure of organisms.

In flowering plants there is large diversity is found in external structure or morphology these are mostly differentiated into the root system (underground) and shoot system (aerial).

The root system consists of roots and their branches while the shoot system consisting of stem, branches, leaves, buds, flowers, and fruits.

parts of flowering plant

The Root

The root is generally non-green, underground, hydrophytic, and positively geotropic. it is a negatively phototropic and descending cylindrical axis of a plant that develops from the radicle of the embryo.

These provide anchorage for the plant, take in water and nutrient which helps the plant to grow.

Structure of Roots

Generally, the roots of plants divided into three main regions

  1. Region of Maturation
  2. Region of Elongation
  3. Region of Meristematic Activity- A few millimeters above the root cap

structure of root

The root is covered at the apex by a thimble-like structure called the root cap. Its main function is to protect the tender apex of the root that makes its way through the soil. Region of meristematic activities found above root cap.

The region of elongation is found at the place where the newly formed cells increases in length and by this the lengthening or elongation or root takes place.

from the region of maturation epidermal cells form very fine and delicate, thread-like structures called root hairs. These root hairs absorb water and minerals from the soil.

Type of root system

The main functions of the root system are the absorption of water and minerals from the soil, providing a proper anchorage to the plant parts, storing reserve food material, and synthesis of plant growth regulators.

  • Formation of the primary root by the direct elongation of radicle in most the dicotyledonous plants. It grows inside the soil. It bears lateral roots of several orders that are referred to as secondary, tertiary, etc. roots.
  • The primary roots and their branches constitute the tap root system, as seen in the mustard plant.
  • There are short-lived primary roots found in monocot plants, which replaced by a large number of roots that originate from the base of the stem constitute the fibrous root system, as seen in the wheat plant.
  • The roots arise from parts of the plant other than the radicle and are called adventitious roots. In some plants, like grass, Monstera, and the banyan tree.
Modifications of Roots
S.No Modification of root Functions Example
1
Modification of Tap Root
I Conical root base is broad, tapering apex and fleshy basal part is shown

Storage of food

Carrot (Daucus carota)
II Fusiform The middle part is swollen, tapering apex, secondary root arises from the apical region.

Storage of food

Radish (Raphanus sativus)
III Napiform The base found thick, root suddenly tapers towards the apex

Storage of food

Turnip (Brassica rapa)
IV Tuberous Tuber like, no definite shape or size

Storage of food

Mirabilis
V Nodulated (tuberculated) Nodules on primary secondary roots . Atmospheric N2 fixation ability. Pea (peasum sativum)
VI Respiratory roots (Pneumatophores) Functions to gas exchange in aerobic respiration. Mangrove plants (sonneratia and Avicenia, Rhizophora)
2
Modification of Adventitious Roots
I

 

Fasciculate Store food Dahlia and Asparagus
II Moniliform Store food Portulaca and Momordica
III Annulated Medicinal value Ipecac (cephaelis)
IV Palmate Medicinal value Orchid
V Reproductive Vegetative propagation Sweet potato and Dahlia
3
Modification of Root For Mechanical Support
I Prop root Arises from nodules of main stems grow vertically downward the soil and anchor. Functions as Mechanical support. Banyan tree (Ficus benghalensis), rubber plant

 

II Stilt root Arises from the stem, enters in soils, consisting of many root caps.

Functions for aditional support, absorption of water and minerals from the soil

Pandanus, Sorghum, Maize
III Clinging Roots Arises from nodes and internodes in week stemmed plants these observed in epiphytes or space parasites

Function for climbing, additional support

Piper betel and pothos
Iv Buttress roots These are large wide roots that arise from the basal part of the stem, spreads in the soil in various directions.

Works for support

Almond and peepal

 

modification of roots

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