Flowers Adapted to Pollination by Different Agencies (Class 12 Biology Practical File)

Pollination is a vital process in flowering plants, and different flowers show unique adaptations based on the pollinating agent—wind, insects, or birds. Wind-pollinated flowers are small, dull, and scentless. They produce large amounts of dry, lightweight pollen that can easily disperse through air. Their stigmas are long and feathery to efficiently catch airborne pollen.

Insect-pollinated flowers are bright, fragrant, and nectar-rich to attract bees, butterflies, and other insects. Their pollen is sticky and rough, helping it attach to insect bodies. These flowers often have specialized structures that guide insects toward nectar while ensuring pollen transfer.

Bird-pollinated flowers are usually large, tubular, and brightly coloured. They produce abundant nectar and have strong floral parts to support bird visits. Their pollen is sticky, aiding effective transfer through the bird’s beak or feathers.

These adaptations help ensure successful pollination and reproduction in plants. This topic is essential for Class 12 Biology practical file preparation.

AIM:- Flowers adapted to pollination by different agencies (wind, insects, birds).

REQUIREMENTS

Fresh flowers of maize or any other cereal/grass, Salvia / Osmium and Brassica (mustard) forceps, hand lens, slide, needle etc.

PROCEDURE

Place the given flower on a slide and observe it with the help of hand lens. Note down the adaptations of the flowers meant for pollination by the external agencies.

Maize Flowers (Anemophilous or Wind Pollinated Flowers)

The flowers of maize show following adaptations for pollination by wind

1. The maize plant is monoecious and bears unisexual flowers. The male flowers are born

in terminal inflorescence while the female flowers are born in axillary inflorescence.

2. Flowers are small and inconscipicous.

3. The flowers are colourless, odourless and nectar less.

4. Flowers are produced above the foliage or placed in hanging position.

5. Both the stigmas and anthers are exerted (i.e., hang outside the perianth).

6. Anthers are versatile, and pollen grains are light, small and dusty.

7. The pollen grains are produced in very large numbers.

8. Stigma is hairy, feathery or branched to catch wind born pollen grains

Salvia Flowers (Entomophilous or Insect Pollinated Flowers)

The flowers of Saliva show following adaptations for pollination by insects.

1. The flowers are showy or brightly coloured for attracting pollinating insects.

2. The flowers are born in verticillate inflorescence to become conspicuous.

3. Flowers secrete nectar to feed visiting insects. Nectar glands are placed in such a position that an insect must touch both the anthers and stigmas.

4. The flowers have landing platform for the insects.

5. The flowers are protandrous with blipped corolla and have turn pipe or lever mechanism.

6. Each stamen has long connective which bears a fertile anther lobe at the upper end and sterile plate like anther lobe at the lower end. The two sterile anther plates block the path of insect.

7. As the insect moves inward a young flower in search of nectar, its head pushes, the anther plates and forces the fertile anther lobes to strike against its back.

8. In older flowers the style brings the stigma in such a position that it brushes against the back of insect and collect pollen grains brought by the insect from a young flower.