Botany Assignment Help




Botany, plant science(s), phytology, or plant biology is a branch of biology that involves the scientific study of plant life. Botany covers a wide range of scientific disciplines concerned with the study of plants, algae and fungi, including structure, growth, reproduction, metabolism, development, diseases, chemical properties, and evolutionary relationships among taxonomic groups. Botany began with early human efforts to identify edible, medicinal and poisonous plants, making it one of the oldest sciences. Today botanists study over 550,000 species of living organisms.

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BOTANY :-->

Botany is a branch of biology that deals with plants. It is a scientific study of plant life. Botany covers a wide range of plants, algae and fungi including their development, growth, structure, metabolism, reproduction and diseases etc.

Some good books that can be recommended for botany are:

Botany in a Day: The Patterns Method of Plant Identification

Botany Illustrated: Introduction to Plants, Major Groups, Flowering Plant Families

Botany for Gardeners

 

Learn Botany (a Sample Article)

Here is a sample of some important topics in botany:

HOW DO PLANTS INCREASE IN NUMBER?

Germination of a seed

Most plants that grow around us have flowers. Such plants are known as flowering plants. Flowers can form fruits. Most ripe fruits have only one or more fully-formed seeds.

A seed has a seed coat and one or two cotyledons. The seed coat protects the seed. A cotyledon is also called a seed leaf.

A seed can grow into a new plant. When the embryo (baby plant) brgins to grow out from a seed, we say the seed has germinated.

Germination is the process of growth of a plant from a seed.

What do seeds need to germinate?

1. Seeds need water to germinate.

2. Seeds need warmth to germinate

3. Seeds need air to germinate

4. Seeds do not need sunlight to germinate

A Seedling

When a seed begins to grow into a new plant, first of all, a white structure begins to grow. It is called the radicle. This is actually the root of the plant. When the root appears from the seed, we say, the seed has germinated. 

  The leaves develop on the shoot after a few days. This young plant is called a seedling. The cotyledons remain attached to the young plant. They provide food to the seedling until its leaves begin to make food.

  The seedling needs the right amount of water, warmth, air, sunlight and fertile soil to grow into a healthy plant.

Seed Dispersal

In nature, seeds germinate in the soil. Once the seeds are fully formed, they move away or disperse from the mother plant. The spreading away of seeds is known as seed dispersal.

  Dispersal of seeds is necessary so that each seed gets enough space, nutrition, water and warmth to grow into a new plant.

How do seeds disperse?

1. Dispersal by Wind e.g. Milkweed

2. Dispersal by animals

3. Dispersal by water e.g. coconut

4. Dispersal by explosion e.g. lady finger

Learn Botany (continued)

REPRODUCTION IN PLANTS

Flowers are the reproductive parts of a plant. A flower may have either the male part or the female part or both.

  There are several ways by which plants produce their offspring. These are categorised into two types:

(i) Asexual Reproduction: In which plants can give rise to new plants without seeds.

(ii) Sexual Reproduction: New plants are obtained from seeds.

ASEXUAL REPRODUCTION

Vegetative propagation: It is a type of asexual reproduction in which new plants are produced from roots, stems, leaves and buds. Plants produced by the method of vegetative propagation take less time to grow. The new plants are exact copies of the parent plant.

Budding: The small bulb-like projection coming out from the yeast cell is called a bud. The bud gradually grows and gets detached from the parent cell and forms a new yeast cell.

Fragmentation: When water and nutrients are available, algae grow and multiply rapidly by fragmentation.

Spore Formation: Fungi on a bread piece grow from spores which are present in the air.

SEXUAL REPRODUCTION

The flowers are the reproductive parts of a plant. Stamens are the male reproductive part are the and the pistil is the female reproductive part. Anther contains pollen grains which produce male gametes. A pistil consists of stigma, style and ovary. The ovary contains one or more ovules. The female gamete or egg is formed in an ovule.

Fertilization

 In sexual reproduction a male and a female gamete fuse to form a zygote. This process is called fertilization.

Pollination

The transfer of pollen from the anther to the stigma of a flower is called pollination.

Epidermis-->

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Epidermis

Epidermis can be referred to three categories namely:

  • Epidermis in botany refers to the outermost layer of cells covering the leaves and young parts of a plant.
  • Epidermis in skin refers to the outer, protective, non-vascular layer of the skin covering the exterior body surface or dermis in vertebrates.
  • Epidermis in zoology refers to the integument layer of the skin of various invertebrates.

Epidermis in Botany

The epidermis which acts as a boundary between the plant and the external environment is a single-layered group of cells covering plants leaves, flowers, roots and stems. It has various functions such as protection against water loss, regulates gas exchange, secretes metabolic compounds and absorbs water and mineral nutrients.

The outermost layer of cells on the plant body usually has several layers. The five structural components of the tissue are as follows:

  • Cuticle- covers the surface of the young stems, leaves, floral organs and apical meristem. It is made up of fatty substance.
  • Stomatal apparatus- apertures in the epidermis surrounded by specialized cells called guard cells and subsidiary cells.
  • bulliform cells- known as motor cells
  • trichomes
  • Roots Hairs- certain root epidermal cells have thin walled extensions called root hairs.

The epidermis is retained throughout the life of leaves, herbaceous stems and floral organs while most woody stems retain it for one or two years, after which it is replaced.

Epidermis in Skin

The epidermis in humans acts as the body’s major barrier against unfavourable environmental conditions. The epidermis is a stratified squamous epithelium, made of differentiated suprabasal keratinocytes and proliferating basal. It is ectodermic in origin. In human, it is the thickest on the palm and thinnest on the eyelids. 95 per cent of the epidermis consists of keratinocytes. The epidermis consists of 5 layers namely:  cornified layer, clear/translucent layer, granular layer, spinous layer, and basal/germinal layer.

The main reason for skin colour variation in modern Homo sapiens is the pigment known as melanin in the epidermis.

Epidermis in Zoology

The epithelium that covers the body of a eumetazoan is called the epidermis. Eumetazoa have a cavity lined with a similar epithelium, the gastrodermis, which forms a boundary with the epidermis at the mouth.

Torus-->

Torus is defined as swelling or bulging projection. It can be any bulging projection for that matter. The term is widely used in literary works of various fields like Architecture, Botany, Anatomy, Geometry.

The torus concerning Biology is described in two respects, Botany and Anatomy.

Torus : Botany

1. Cell wall structure:

It is the thickened central part of pit membrane, classically seen in bordered pits. It is guarded by borders and surrounded by pit chamber. this chamber communicates with adjacent cell through pit aperture. It is a structure of secondary cell wall. The cell walls containing pits are known as pitted. Pits develop in pairs i.e., when pit is present on the secondary wall of one cell, it is complemented by a similar or dissimilar pit on the opposite side of adjacent cell. Such types of pis forming functional and morphological units are called pit pairs.

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The torus is known to act as a valve blocking the pit when there is pressure discrepancy on either side of the membrane. Eg: damage to tracheary elements of adjacent wall.

2. Torus/Thalamus/Receptacle:

This torus (better known as Receptacle) is the expanded portion of peduncle over which the whorls of flower are arranged. It is mostly concave but may be flat or even convex, depending on which the arrangement of gynoecium is described (hypogynous, perigynous and epigynous flowers).

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Torus : Anatomy

Any bulbous swelling inside the body is called torus. The most well known of these is the torus tubarius. It is also called as tubal elevation and corresponds to the base of cartilaginous part of Eustachian tube. It is present as a cushion, superior to the nasopharyngeal end of auditory tube and covered by only mucous membrane. From the lower part of torus posteriorly, a salpingopharyngeal fold arises, carrying the corresponding muscle. On the anterior side, another fold called salpingopalatine fold extends from upper part of torus to soft palate.

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