What is Plant Morphology and Anatomy?

The study of life and organisms is biology. The cell is recognized as the basic unit of life by biology. From ancient Greek, biology is recognized. Modern biology deals with the recent developments in Science.

Morphology is a discipline of biology concerned with the study of organisms' form and structure and their different structural characteristics. The plant morphology includes roots, stems, leaves. 

Plant anatomy, often known as phytotomy, is the study of the internal structure of plants.

The plant anatomy includes leaves, stem, and flower.

Parts of Plant Anatomy

Below are various parts that come under plant anatomy.

Flowering plant

Over 300,000 species of land plants are present. They are also known as seed-bearing plants. Seed-bearing plants are angiosperms. During Triassic, period angiosperms evolved from gymnosperms. Almost 140 million years ago first flowering plants evolved. 

The flower is a reproductive part of the plant. This character distinguishes it from other seed plants. By the process of pollination, angiosperms reproduce. The morphology of plants includes two systems: the root system and the shoot system. The root is the underground portion of the plant, whereas the shoot is the portion of the plant present above the ground. 

Root system

The brown, underground portion of the plant represents the root. The root system contains roots with root branches. Root systems are of three types.

Taproot, Fibrous, and Adventitious root system

Taproot system: In dicot plants, the taproot system is seen. From the radicle of germinating seed, it develops. It develops along with primary roots and branches, giving rise to the taproot system. The structure of the taproot system is tapering. An example of a taproot system is mustard grams.

Fibrous root systems are often created by thin, modestly branched roots emerging from the stem. A fibrous root system is found in all monocotyledonous plants and ferns.

Adventitious roots are those that form from areas of the plant other than the radicle. These roots can grow from the wounded root, stem nodes, internodes, branches, or other tissue. An adventitious root system is a collection of adventitious roots and their branches. Marigold and grass have an adventitious root system.

The Fibrous root system

In ferns and monocot plants, a fibrous root system is present. From primary roots, this root develops. It does not grow deep in the soil. The structure of the fibrous root system is not wide, and its structure is somewhat of fiber type.

The Adventitious root system: Other than radicle, these adventitious roots can arise from any part of the body. Mainly it is present in monocot plants.

In roots, three regions are present:

• The root cap
• The region of maturation
• The region of elongation

Shoot system

The stem is an essential part of the shoot system. On the stem, branches, leaves, fruits, flowers appear. The shoot arises from the plumule of the embryo. Initially, young stems are green in color, and later it becomes dark brown. Modification of the stem occurs depending on the function it performs. 

Characteristics of stem:

• The stem arises from the plumule and epicotyl of an embryo.
• The growth of the stem occurs towards the light.
• At the apex of the stem, a terminal bud is present.
• The shoot is differentiated into nodes and internodes in the case of angiosperms.
• Younger stems are generally green in color.
• Multicellular hairs are present on the stem.
• Fruits and flowers arise on stems and branches.
• Stem modification happens depending on the function of the stem.
• Runners, Suckers, Climbers, Tubers, Rhizome, Tendrils, Thorns.

Morphology of leaves

Leaves are flattened, and laterally borne structures present on the plant. It is the main photosynthetic organ of plants. Absorption of light and exchange of gases occurs through the leaves.

The morphology of the leaf includes petiole, leaf base, and lamina. The petiole structure is swollen, and their growth occurs at nodes and in the axile of leaves, bud is present. Venation is defined as an arrangement of veins and veinlets. Due to the presence of chlorophyll, leaves are green in color. Stomata are present in the leaf as a tiny opening through which an exchange of gases occurs. 

Leaves are classified as simple and compound based on the pattern of the leaf blade. 

Characteristics of leaves:

• Leaves arise from the node
• Its origin is exogenous 
• A bud is present on its axis
• Limited growth occurs in leaf
• Apical bud is not present in the leaf.

Function of leaves

The main function of the leaf is photosynthesis, along with other functions such as transpiration, guttation, storage.

Flower

Morphology of flowering plant: The reproductive part of the plant is a flower. The inflorescence is defined as an arrangement of flowers on the floral axis. 

The morphology of flowering plants includes four different whorls present in flowers known as calyx, corolla, androecium, and gynoecium.

Type of Plant Anatomy

A tissue collects similar cells and their extracellular matrix from the same origin that work together to perform a specified function. The functional grouping of several tissues results in the formation of organs or particular parts.

Two types of plant anatomy are Meristematic and Permanent

Meristematic tissue

Meristematic tissue is made up of actively dividing cells. It comprises Apical meristem, Intercalary meristem, Lateral meristem

Apical Meristem: Apical meristem is present at the tip of the plant. It helps in the formation of primary tissue. An example of apical meristem is vascular and ground tissue.

Intercalary Meristem: It is present between mature tissues, for example, grass.

Lateral Meristem: Secondary tissues are formed from the lateral meristem, for example, cambium.

Permanent tissue

Permanent tissue is a type of tissue that stops division after a specific function is achieved.

They are divided into simple and complex tissue.

Simple tissue: A simple tissue is made up of similar cells with the same structure and functions.

Complex tissue: A complex tissue is composed of more than one type of cell, which performs similar functions.

Epidermal tissue system

The epidermal tissue system comprises the outer covering of plants. Cuticle, stomata, epidermis, epidermal extensions comprise the epidermal tissue system. It helps in the regulation of gaseous exchange and water loss by transpiration.

In dicots, the guard cells are bean-shaped structures having chloroplasts. Dumbbell-shaped guard cells are present in grasses. Unicellular root hairs and multicellular trichomes are also present. 

The Ground tissue system

It is found between the epidermis and vascular tissues and comprises a major cluster of cells. An example is a cortex, a pericycle. 

The Vascular tissue system

Its anatomy comprises the xylem and phloem. Between xylem and phloem, cambium is present in the case of Dicot. It is being formed from the cambium. In Dicots, it is of open type. 

Structure of Dicot root

The outermost layer is epiblema, in which no root hairs are present. In the cortex, several layers are present; the innermost layer is the endodermis; on endodermis, Casparian strips are present. It is formed of waxy material called suberin. The second layer is the pericycle, from which lateral root and vascular cambium arise. Vascular bundles are present in two to six numbers. The nature of the vascular bundle is radial and exarch.

Structure of monocot root

The nature of the hypodermis is sclerenchymatous. Scattered, conjoint, and closed vascular bundles are present. 

Dicotyledonous leaf

Due to distinct dorsal and ventral sides, it is also known as a dorsiventral leaf. The epidermis is present on both the upper and lower surface. On the abaxial epidermis, more stomata are present. 

The nature of mesophyll cells is parenchymatous, and they can perform the process of photosynthesis. It is divided into palisade and spongy parenchyma. Bundle sheath cells surround the vascular bundle.

Monocotyledonous leaf

Since in monocot leaf, both sides are similar, therefore, it is known as an isobilateral leaf. Venation is reticulate. Both the surfaces are covered by epidermis. The differentiation of mesophyll cells is not there. Bulliform cells are present in grasses which are specialized epidermal cells. 

Context and Applications

This topic is important in Bachelor of Science and Master of Science entrance exams

• Bachelors in Science (botany and zoology)
• Masters in Science (botany and zoology).