Sexual Reproduction in Plants

biology class 12

What does a young anther look like?

A homogeneous mass of meristematic cells surrounded by epidermis.

How does the anther become 4-lobed?

By differentiating into four lobes, each with a row of archesporial cells.

What are archesporial cells?

Special cells with conspicuous nuclei and dense cytoplasm; they divide to form parietal and sporogenous layers.

What divisions do archesporial cells undergo?

Periclinal division → forms outer primary parietal layer & inner primary sporogenous layer.

What does the primary parietal layer form?

By further periclinal & anticlinal divisions, it gives rise to:

1. Epidermis

2. Endothecium

3. Middle layers

4. Tapetum

What does the primary sporogenous layer become?

It divides to form sporogenous cells → microspore mother cells (MMCs).

How are MMCs initially connected and then separated?

Connected by plasmodesmata, then separated by callose wall formation.

Final structure of mature anther?

4-lobed with 4 microsporangia, each with layers: epidermis, endothecium, middle layers, tapetum, and pollen mother cells inside.