Here is your short essay on Morphology

Angiosperms (Gr. Angeion: case; spermos: seeds) are a group of plants characterized by production of flowers and formation of seed(s) within a fruit.

The plant body shows a great range in size and diversity in form. This led to the morphological and physiological differentiation between various parts of plant body which gave thus the plant organ concept.

The plant body is the sporophyte which is made up of several fundamental parts or organs. The morphologists divide the plant body into three basic organs – the root, stem and leaf. The main axis of the plant body consists of a root, normally developing under the ground, and a stem normally growing up.

The root bears a number of lateral structures similar to it and forms the root system. The stem holds lateral appendages in the form of leaf and branch. The stem along with leaf is called the shoot and forms the shoot system.

The root system and the shoot system together constitute the vegetative body of the angiosperm as the plant grows and reaches maturity; it forms flowers, fruits and seeds.

These three constitute the reproductive system of the plant as the flower forms the fruit and seed after fertilization. The seed when germinates, gives rise to new plant and serves the function of multiplication of the plant.

The Root

The root is the underground or descending portion of the axis of the plant. The radicle of the embryo gives rise to root. It is non-Greek and not having nodes and internodes. Anatomically branch root arises from an inner layer, i.e., pericycle. So it is endogenous in origin.

It is positively geotropic, negatively phototropic and positively hydrotropic. The root developed from the radicle is called primary root. If primary root persists and gives rise to root system, it is called the tap root system.

The lateral branches, those coming out from the primary root are known as secondary roots. The branch roots coming out from the secondary root are known as tertiary roots. The tap root branches in an acropetalous manner. Mainly tap roots are formed in dicotyledonous plants.

Most of the monocotyledonous plants show a different type of root system. In this case, although the radicle comes out first during germination as in dicotyledons and gives rise to primary root, this does not persist.

A number of roots are developed from the base of such radicle, e.g., rice. Such roots behave like primary roots and are known as seminal roots. Along with these, some fiber-like roots come out from the base of the plumule or lowermost node to form a distinct root system, known as fibrous root system.

A root can be differentiated into four organographies regions root-cap region, region of elongation, root hair region and region of maturation.

Characteristics of the root:

1. Root is the descending portion of the axis of the embryo and grows away from light. It is non-Greek in color.

Exceptional cases are seen in the aerial roots of Tinospora, the root of which is green when exposed to light for a prolonged period. In some epiphytic orchids and submerged roots (e.g., Trapa), the roots are green in color.

2. It generally does not bear buds; however, the roots of Aegle, Trichosanthes bear buds for vegetative propagation.

3. At the terminal portion of the root there is a root- cap to provide a protective sheath to the tender root meristem. In Pandanus, the root-cap is distinct and multiple in nature. In aquatic plants root pockets are present.

4. The root bears unicellular hairs, a little behind the apex. These are having thin walls made of cellulose and are short-lived. When older root haris perish, newer ones are formed towards the apex.

5. Nodes and internodes are absent in the roots.

6. Lateral roots are developed from an inner layer, i.e. pericycle. So, these are endogenous in origin.