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

This is responsible for plant growth and is located in the tips of both roots and shoots, actively dividing to produce new cells for elongation and development. Sieve Tube: This is part of the phloem tissue responsible for transporting dissolved organic substances.

Thallophytes are a polyphyletic group of non-motile organisms traditionally described as "thalloid plants", "relatively simple plants" or "lower plants". They form a division of kingdom Plantae that include lichens and algae and occasionally bryophytes, bacteria and slime moulds.

The gymnosperms (gymnos : naked, sperma : seeds) are plants in which the ovules are not enclosed by any ovary wall and remain exposed, both before and after fertilisation. The seeds that develop post-fertilisation, are not covered, i.e., are naked.

Cryptogamae - A plant that reproduces by spores without flowers or seeds. It includes all non-flowering plants such as algae, fungi, lichens, mosses and ferns. It is further subdivided into three parts: Thallophyta (example, Algae,and Fungi), Bryophyta (example, Mosses) and Pteridophyta (example, Fern).

Plant Tissue : Types - Meristematic tissue - These tissues have the capability to develop by swift division. Types - Apical meristem (increases the length of the plant), Lateral meristem (increases the thickness of the plant), Intercalary meristem (increases the size of the internode).
Permanent tissues - These cells have lost their ability to distribute but are specialized to offer elasticity, flexibility and strength to the plant. Types - Simple Permanent Tissue (sclerenchyma, collenchyma and parenchyma). Complex Permanent Tissue (phloem and xylem).

Riccia : It is an Example of Bryophyta (small plants that grow in shady and damp areas). Thallophyta - A division of the plant kingdom including primitive forms of plant life showing a simple plant body. Examples - Ulothrix, Cladophora. Types - Algae and Fungi.

Meristems are regions of actively dividing cells in plants responsible for growth and development. They are classified as Apical - It is present at the growing tips of stems and roots and increases the length of the stem and the root; Lateral - The girth of the stem or root increases; and Intercalary - The meristem at the base of the leaves or internodes (on either side of the node) on twigs.

It is present at the growing tips of stems and roots and increases the length of the stem and the root. The girth of the stem or root increases due to lateral meristem (cambium). Intercalary meristem seen in some plants is located near the node.

Collenchymas tissue: These living cells provide support and flexibility to growing plant parts. Parenchyma: These living cells are involved in various functions like photosynthesis, storage, and support.

The ovules after fertilisation, develop into seeds. A seed is made up of a seed coat and an embryo. The embryo is made up of a radicle, an embryonal axis and one (as in wheat, maize) or two cotyledons (as in gram and pea). Coleoptile - The first leaf of a monocotyledon which forms a protective sheath about the plumule.