Botany Chapter on Plant Reproduction

Study Notes

Perennials

Plants that live for three or more years.
Examples include mango, peepal, and neem.
Perennials may bloom in their first year, flowering profusely.
Some perennials overwinter indoors (e.g., Dahlia).

Sexual Reproduction in Plants

Begins with the formation of gametes.
Gametes can be formed by the same individual or different individuals.
Gametes fuse to form a zygote.
Plants reproduce sexually during their mature phase.
The vegetative phase precedes the mature phase of reproduction.

Flower Structure

Calyx: Referred to as sepals, they are green in color and perform photosynthesis.
Corolla: Referred to as petals, they are brightly colored and attract pollinators (insects or birds).
Androecium: The male reproductive part. It consists of stamens.
- Stamen: Consists of a filament (stalk) and an anther. The anther has two lobes, each containing two pollen sacs that develop pollen grains. Each stamen is dithecous (having two thecas).
Gynoecium: The female reproductive part. It consists of a pistil.
- Pistil: Consists of a stigma, style, and ovary. The stigma is the landing platform for pollen grains; the style connects the stigma to the ovary; the ovary contains ovules.

Flower Function

The androecium and gynoecium are known as essential whorls of flowers.
The female part is a long tube-like structure called a pistil, part of the gynoecium.
The male part consists of stamens. Each stamen has two distinct parts: a filament (stalk) and the anther. Each anther has two lobes, and each lobe contains two thecas with pollen sacs.
Calyx and corolla are collectively known as non-essential or accessory whorls.
Calyx is known as sepals. Sepals are green in color and perform photosynthesis.
Corolla is known as petals. Brightly colored to attract pollinators. Androecium is the male part that consists of stamens. The female part called gynoecium consists of three distinct segments called a stigma, style, and an ovary.

Pollen

Pollen is formed in the pollen sacs in the anther.
Pollen grains are often clustered.

Megasporangium (Ovule)

The ovule is a small structure attached to the placenta by a stalk called the funicle.
The body of the ovule fuses with the funicle at the region called the hilum.
Each ovule has one or two protective envelopes called integuments.
The integuments encircle the ovule except at the tip, where a small opening called the micropyle is present.

Female Gametophyte

In most flowering plants, one of the megaspores is functional, while the other three degenerate.
The functional megaspore develops into the female gametophyte (embryo sac).
This method of embryo sac formation from a single megaspore is termed monosporic.

Description

Explore the fascinating world of perennials and their reproductive strategies in this quiz. Dive into the intricate structures of flowers, including their various parts and functions. Test your understanding of sexual reproduction in plants and the life cycle phases they undergo.