Sexual Reproduction in Flowering Plants

Question 1

The stamen consists of two parts -

Answer 1

a long and slender stalk called the filament and a terminal generally bilobed structure called the anther

Question 2

Structure of microsporangia

Answer 2

It is surrounded by four wall layers - the epidermis, endothecium, middle layers and the tapetum. The outer three wall layers perform the function of protection and help in the dehiscence of the anther to release pollen. The innermost layer nourishes the pollen grains. The cells of the tapetum possess dense cytoplasm and generally have more than one nucleus.

Question 3

What is sporogenous tissue

Answer 3

A group of compactly arranged homogenous cells which occupy the centre of each microsporangium.

Question 4

What is microsporogenesis

Answer 4

The process of formation of microspores from a pollen mother cell (PMC) by meiosis is known as microsporogenesis. As the anther develops the sporogenous tissue undergoes meiotic division to give rise to microspore tetrads. As the anthers mature and dehydrate they dissociate from each other and develop into pollen grains.

Question 5

Pollen Germination

Answer 5

Pollen grains have a prominent two-layered wall. The hard outer layer called the exine is made up of sporopollenin, which is the most resistant organic material known. they can withstand high temperatures and strong acids and alkali. Pollen grains have apertures called germ cells, where sporopollenin is absent.
The inner wall of the pollen grain is called the intine and it’s a thin and continuous layer made up of pectin and cellulose.
The cytoplasm of the pollen grain is surrounded by a plasma membrane.
When the pollen grain is mature it contains a vegetative and a generative cell. The vegetative cell is bigger and has an abundant food reserve. The generative cell is small and floats in the cytoplasm of the vegetative cell, it is spindle-shaped with dense cytoplasm and a nucleus.

Question 6

A pistil consists of

Answer 6

Stigma - Landing part
Style - Elongated part, joining the stigma and the ovary
Ovary - The bulge (lmao what)
Inside the ovary is the ovarian cavity (no shit sherlock) or locule and within the ovarian cavity lies the placenta. Megasporangia or ovules rise from the placenta.

Question 7

Structure of Megasporangia

Answer 7

1. Attached to the placenta by a stalk called a funicle (fun uncle)
2. The ovule fuses with the funicle in a region called the hilum.
3. Each ovule has one or two protective envelopes called integuments. They encircle the nucellus except at the tip where a small opening called the micropyle is organized.
4. The opposite end is the chalaza, representing the basal part of the ovule.