Question

a) Draw a labelled schematic diagram of the transverse section of a mature anther of an angiosperm plant.
(b) Describe the characteristic features of an insect-pollinated flower.

Answer 1

Hint: Anther is the male reproductive part of the flower. It is present in the stamen and houses as a two-lobe structure over a thread-like stalk or filament. It acts as a reservoir for pollens.

Complete answer:
To answer this question, we must know about the structure of the anther. The anther is made up of two lobes which are connected by a connective. Each lobe contains longitudinally placed two chambers of pollen. Each pollen chamber is called a microsporangium which contains a large number of microspores or pollen grains.

The mature anther has the anther cavity which is enclosed by an anther wall.
i) Anther wall- It has the following layers epidermis, endothecium, middle layers and tapetum. The epidermis is protective in nature. The tapetum is responsible for controlling the fertility of the pollens. ii) Anther Cavity- It is then filled with pollen grains. The meiotic division takes place here to produce haploid pollens.

iii) Connective- It consists of sterile tissue which is surrounded by anther lobe. It is vascularised in nature.

b) The characteristics of insect-pollinated flowers are:
- The flowers are coloured and attractive.
- They emit a sweet smell.
- The flowers are larger in size.
- The flowers are rich in nectar.
- The pollen grains are large, sticky and are spinous in nature.

Note: The pollination by insects is called Entomophily. Butterfly, wasps, beetle, flies are common insects that bring about pollination. The honey bee is also one of the major insect pollinators.