Table of Contents
Introduction
Plants are an important part of the ecosystem. All living things on earth depend on plants or plants directly. Among the various parts of the plant, the leaf is the most important.
Basically, leaves have two functions: photosynthesis and respiration. In some plants, it takes the responsibility to reproduce.
Plant Morphology also describes the visible species of plants. Plant Morphology is very useful for the visual identification of plants. It is a study of the structure, development, and condition of plants. Four Essential Areas of Research exist in this field and each area exceeds the other area of biology.
Leaf
Leaves small, flat organs responsible for photosynthesis in plants. It grows side by side in a node. It is an integral part of the photography system and derives from shooting apical meristems.
The leaf structure is described below in detail:
Parts of the Leaf
Generally, the base of the leaf, the petiole, and the lamina, together form the main parts of the leaf.
- Leaf Base: This is the part where the leaf attaches to the stem. The base of the leaves has a leaf-like structure called stipules. In plants such as paddy, wheat, and other monocotyledons, this leaf base is broad and closes the stem.
- Petiole: Petiole is a long, slender stem, which connects a leaf to the stem.
- Lamina: Also known as leaf blade. It is a green, flat area of leaves. It consists of a small artery with branches and veins. The artery that runs through the center of the lamina is called the midrib. The Midrib divides the lamina surface into two parts. These arteries and veins provide leaf strength and aid in the transport of water and other substances.
Types of Leaves:
There are two broad categories of leaves – simple and compact, divided into different groups based on their shape, size, stem structure, flowering and flowering plants, and various other body features.
The two different types of leaves found in a plant are:
Simple Leaf
When a single lamina is attached to the main stem with a petiole, the leaf is said to be light. The simple leaf can be cut to any depth but not down to the center or petiole. Eg, Guava leaves
Combined Leaf
A compact leaf is a leaf made up of two or more tracts. In a compact leaf, the leaf midrib is folded into separate strips and connected by a single petiole. For example, Pea, palm leaves.
The fused leaves are further subdivided into the following types of leaves:
Palmately Compound Leaf
In the palm leaf joint, leaflets are attached to the end of the petiole. Eg, silk cotton.
These can be divided into:
- Unifoliate: These types of leaves have only one leaf. Eg, Citrus
- Bifoliate: These leaves have two leaflets. For example, Balanites
- Trifoliate: These leaves have three leaflets coming from the same place. Eg, Oxalis
- Quadrifoliate: These leaves have four leaflets from the same place. Eg, Marsilea
- Multifoliate: This type of leaf contains many leaflets from the common pint. Eg, Bombax
Pinnately Compound Leaf
In a composite leaf, the leaf midrib is divided into several leaflets and all are connected by a common axis. Eg, Neem.
These can also be divided into:
- Pinnate: A compound leaf with an axis on each side of the midrib is known as a pinnate leaf.
- Unipinnate: A leaf with a leaf on each side of the axis. Eg, cassia
- Bipinnate: Here, the second paper-axis is produced by the central axis. Eg, Acacia
- Tripinnate: Here, pamphlets with high-resolution leaflets from the second axis. Eg, Moringa
- Decompound: A leaf with more than three wings. Eg, old coriander leaves
- Paripinnate: A leaf with no leaf retaining. Eg, Cassia
- Imparipinnate: A leaf with an unusual terminal leaflet. Eg, Pea
Leaf Functions
The main function of the leaves is photosynthesis. Photosynthesis is the process by which a plant converts sunlight, carbon dioxide, water, and other substances into sugars and other organic matter. The leaves contain a pigment called chlorophyll, which is essential for this process. And a pigment that gives a green color to the leaves.
- Transpiration: The process of extracting excess water from a plant is called transpiration. This occurs in a structure on a leaf called a stoma. It is a kidney-shaped structure that lives in pairs. It opens to release more water and closes when the water content is low.
- Guttation: It is also the process of extracting excess water from a plant. But it happens when the stomata remain closed. It occurs at the edges of the leaves where the xylem is located.
- Storage: Since the leaves must contain food, they must retain the nutrients needed for the process of photosynthesis.
- Protection: A few leaves are prepared to protect plants. For example, Opuntia converts leaves into spines.
Natural Habits Found in Leaves
During their emergence, the leaves have developed in many structural ways especially to provide life and/or reproductive benefits to a wide variety of plants.
Some of these evolutionary situations are discussed in the following points:
- Some leaves (especially in plants that grow in aquatic environments and may be completely submerged or partially submerged in water) produce a waxy coating on their leaves. On the other hand, the leaves of some plants have microorganisms and nanostructures in place to prevent rain and humidity. This prevents the adhesion of dirt to the leaf area which may prevent light and openness of the stomata in photosynthesis.
- The leaves are divided into leaflets (composite leaves) that withstand strong winds and promote a cooling effect.
- Some leaves (plants found in arid areas) have evolved to produce hairs in their areas that help retain moisture. These hairs also help to create a border layer and prevent moisture loss.
- In plants that grow in large sunlight (e.g. Fenestraria), the leaves may be invisible or partially covered and allow light to pass only through the flexible leaf window of photosynthetic activities in the inner leaf area.
- The anatomy of Kranz and the delicate material of the leaves are also special features of the leaves.
Also read: Important Topic OF Biology: Animal Tissues
FAQs
What is leaf morphology? Briefly describe the different types of leaves found in plants.
Leaf morphology is the science of plant leaf structure. It involves the study of various forms, structures, and modifications that leave improvements to enhance their photosynthetic abilities. And although photosynthesis is the primary purpose of the leaf, detailed research shows that the leaves can perform several important functions in a plant, from successful reproduction to survival in harsh climates, all this through its modification of structure and function.
Describe the different mutations found in the leaves of different plant species.
As we have discussed above, the leaves of plants show many genetically modified species. At the basic level, the leaves are divided into simple leaves and grouped based on how they grow on a branch or plant stem. The simple leaves are lobed structures and do not separate with leaflets. Although compact leaves can grow into separate leaflets and each of these leaflets has a small petiole on its stem.
How do leaves grow on a plant?
According to the partial root theory proposed by Agnes Arber, the leaf originates from the leaf primordia found at the top of the shoot, so it is a partial shoot. In its early development, these primordial cells reflect the dorsoventral apex of the apex to form leaf-like structures. The simple leaves grow farther away from the top of the shoot than the fused leaves. In leaf development studies, it was found that clustered leaves can grow into three distinct shoots. Molecular genetic research has now confirmed the notion that composite leaves reflect the characteristics of both shoots and leaves.
