Question

In which one of the following plants is the lever mechanism of pollination observed?
A.Salvia
B.Jasmine
C.Bougainvillea
D.Butea

Answer 1

Hint: Lever mechanism of pollination is a characteristic feature of the Labiatae family which promotes Entomophily, which means pollination with the help of insects.

Complete answer:
Pollination is the mechanism by which pollen grains from the male anther is transferred to the female stigma in a flower. The pollen grain fuses with the egg in the flower leading to mating of the male and female gametes.
Option A: Salvia is an example of lever mechanism of pollination since it belongs to the Labiatae family. Therefore, this is the correct option. In this, the pollinator comes to the male flower to get nectar it ends up pushing the posterior anther theca. This lever movement causes the stamens to move and thereby the pollen gets deposited on the pollinator.

Option B: Jasmine belongs to the Oleacaece family while the lever mechanism of pollination is followed in the Labiatae family there for option B is the incorrect option. Normally, self pollination is seen in jasmine.

Option C: Lever mechanism of pollination is followed in the Labiatae family, whil bougainvillea belong to the Nyctaginaceae family and in them cross pollination is usually seen. So, option C is an incorrect option.

Option D: Butea belongs to the Fabaceae family while the lever mechanism is followed in the Labiatae family and they are generally pollinated by the help of bees. Therefore, option D is an incorrect option.

Hence, the correct answer is option (A)

Note: In this lever mechanism of pollination, the corolla has a spreading upper lip, which acts as a landing place for the insect. When the insects land on the lower lip of the corolla and in its endeavour to obtain nectar that is secreted by the hypogynous disc, pushes the sterile lobes of the stamen inwards. Due to this the upper half of the connective with the fertile lobes act as a lever. Then the other lobe comes down and sheds the pollen on the back of the insect.