Railway Science (Biology – Plant Kingdom) (Part-II)

Intercalary meristems, found at leaf bases, and promote plant elongation in nodes and internodes. They aid longitudinal growth in stems and leaves, especially in grasses. They are present in monocots at the base of leaf primordia, and enable petioles to extend leaves above water surfaces through their activity.

It was first used by Carl Nageli in 1858. Function - Transportation of water from roots to stems and leaves. Parenchyma - It is composed of living cells. Function - Converts sugar into insoluble starch and stores it for future use. Collenchyma - Simple permanent tissue found in plants; Present in the mesophyll of leaves that contain chloroplast; Almost completely absent in monocots. Aerenchyma - Present in leaves, stems, and roots of the plants. It is richly found in Hydrophytes; Helps for the transportation of oxygen and reduces cellular oxygen demand in plants.

Epidermal cells on the aerial parts of the plant often secrete a waxy, water resistant layer on their outer surface. This aids in protection against loss of water, mechanical injury and invasion by parasitic fungi.
Since it has a protective role to play, cells of epidermal tissue form a continuous layer without intercellular spaces.
Connective tissue: Supports and binds other tissues of the body. Example - Adipose, Cartilage, Bone, Blood and Lymphatic tissues.

This process of taking up a permanent shape, size, and a function is called differentiation. Cells of meristematic tissue differentiate to form different types of permanent tissue. On the basis of their position in the plant body, meristems tissues are classified as - apical, lateral, and intercalary.

Parenchyma cells are involved in the storage of starch, sucrose, protein, water, phenol derivatives, many mineral substances, etc. They are live cells. They are usually loosely packed so that large spaces between cells (intercellular spaces) are found in this tissue.

Gymnosperms: These are seed-producing plants like pines and conifers. Pteridophyta: These are also known as ferns and have vascular systems. Bryophyta: These are non-vascular plants like mosses.

Some examples of halophytes are mangroves, saltwort, and pickleweed. Macrophytes - Large plants that live in water. Examples - cattails, hydrilla, water hyacinth and duckweed.
Xerophytes - Plants that live in dry environments. Examples - Agave, Acacia trees, Joshua trees, Oleander. Hydrophytes - Plants that live in water. Examples - Trapa, Vallisneria, Potamogeton, Salvinia.

Examples - Muscle tissue, bone tissue, and nervous tissue. Meristematic tissue - A type of tissue that is found in plants and is responsible for growth. It consists of cells that are constantly dividing and differentiating into new cells. Epidermal tissue - a type of tissue that covers the outside of the body. It consists of cells that are tightly packed together and form a protective barrier. Nervous tissue - A type of tissue that makes up the nervous system. It consists of cells that are specialized for sending and receiving signals.

Thallophyta is a plant division comprising primitive forms with simple plant structures, ranging from unicellular to large algae, fungi, and lichens. Thallophytes are characterized by their lack of true roots, stems, or leaves.

In plants, this refers to sclerenchyma, which consists of dead cells with thickened cell walls mainly composed of lignin. These cells lack living protoplasm due to the loss of cytoplasm and organelles during their maturation process.