Question

Describe the various modes of fixation of anther over filament.

Answer 1

Hint: Stamen represents the male reproductive organ of the flower. These organs are filament and anther. Filament can vary in length within a flower. Anther is a bilobed structure with each lobe having two chambers called pollen sac which produce pollen grains.

Complete answer:
On the basis of attachment of anthers to the filament, stamen can be classified in to the following types:
1. Basifixed: In this type of attachment filament attached to base part of the anther.For example, mustard, cassia.
2. Adnate: In this type filament runs throughout the length of the anther. For example magnolia,water lily
3. Dorsifixed: In this type filament attached to the dorsal side of the anther. For example: citrus, passiflora.
4. Versatile: This type of attachment is diversified but anther can swing freely over filament. For example grasses, eucalyptus.

Additional information:
Dehiscence of anther: Anther burst when they become ripe and discharge dry pollen. This is called dehiscence and when this process takes place that is called anthesis
There are different types of dehiscence:
When the anther lobe burst along the longitudinal sutures this is called longitudinal dehiscence. For example datura.
Some unilocular anthers discharge pollen through transverse suture. This is transverse dehiscence.
In porous dehiscence, pollen grains discharge through apical process. For example potato, brinjal.
When anther wall opens out like trap doors releasing the pollen. This is called valvular dehiscence.

Note: In flowers male reproductive organ is androecium. Each stamen consists of fertile anther joined with filament with the help of connective tissue.