Agents of Pollination

Adaptations for Wind Pollination:

Wind pollination is also termed as anemophily and takes place through the wind.

i. Flowers are small, colourless, inconspicuous, nectar less and become arranged as inflorescence.

ii. The anthers are well exposed for the easy dispersal of pollen grains.

iii. Pollen grains are small, light, dry, dusty, non-sticky and sometimes even winged.

iv. The stigmas are large, hairy and feathery or branched to catch the air borne pollen grains.

v. Examples of wind pollinated flowers are grass, sugarcane, bamboo and coconut, etc.

Adaptations for Water Pollination:

Water pollination is also termed as hydrophily and mode of pollination is water. It is quite rare in flowering plants and is limited to about 30 genera, mostly monocotyledons.

i. It is very common in plant groups such as algae, bryophytes and pteridophytes. Flowers are small, colourless, inconspicuous, odourless and nectar-less and pollen grains and stigmas are generally unwettable.

ii. The stigmas are long and sticky, e.g., Vallisneria, Hydrilla and Zostera.

iii. Not all aquatic plants use water for pollination. In a majority of aquatic plants, the flowers emerge above the level of water and are pollinated by insects or winds as in land plants, e.g., water hyacinth and lily.

iv. In Vallisneria, the female flower reach the surface of water by the long stalk and pollen grains are released on to the surface of water. They are then carried by the passive water currents.

v. In most of the water pollinated species, pollen grains are protected by mucilaginous covering.

Adaptations for Insect Pollination:

Inject pollination in also termed as entomophily.

Insect-pollinated flowers are large, colourful, fragrant and rich in nectar.

i. A number of flowers are clustered into an inflorescence to make them conspicuous.

ii. Flowers have nectar glands and are highly fragrant to attract insects.

iii. The surface of pollen grains is sticky due to exine layer and stigma is sticky due to mucilaginous layer.

iv. Nectar and pollen grains are floral rewards for the insect pollinators.

v. In some species, floral rewards are to provide safe place to lay eggs, e.g., for the tallest flower of Amorphophallus (about 6 feet in height).

vi. In plant Yucca, moth and the plant, cannot complete their life cycles without each other. The moth deposits its eggs in the locule of the ovary and the flower, in turn plant gets pollinated by the moth. The larvae of the moth come out of the eggs as the seeds start developing.