Question

The smallest pollen grain occurs in
A. Myosotis
B. Mirabilis
C. Zostera
D. Eucalyptus

Answer 1

Hint: Pollen grains considered as a male gametophyte. Pollen grains are normally spherical around 25-50 micrometer in diameter. The pollen grain is spherical in shape and it has 25-50 micrometer in diameter. Pollen grain has a two-layered wall, an outer wall called an exine and an inner wall called an intine.

Complete answer:
A. Myosotis: The smallest pollen grains are found in this plant. It is around 0.006mm in diameter. It is a flowering plant both sexual and asexual reproduction takes place. In sexual reproduction, pollen grains differ in diameter in the myosotis plant. Pollen grains shoot up on the surface of the stigma. The flower forms a pollen tube. Pollen cytoplasm is responsible for the growth of the pollen tube. Two sperm cells are moved inside the pollen tube and transfer into embryo sac inside the ovule fertilization takes place.
So, option (A) is the correct answer.

B. Mirabilis: The best familiar species is Mirabilis Jalapa. Commonly called a four o’clock plant. Several species found in this plant. Usually, this plant is used for ornamental purposes and has medicinal properties. The smallest pollen grains are not found in this plant.
So, option (B) is incorrect.

C. Zostera: The largest pollen grain present in the Zostera plant. About 2500 micrometer in length. Propagating organs found in plants and trees. These are minute bodies that connect female propagating organs of the plant to ease fertilization.
So, option (C) is incorrect.

D. Eucalyptus: Eucalyptus is a genus above 700 kinds of flowering trees. Eucalyptus leaves possess a medicinal attribute. It reduces inflammation and reduces pain etc. The smallest pollen grains are not found in this plant.
So, option (D) is incorrect.

Hence, the correct answer is option (A).

Note: Myosotis is commonly called Forget me not. Myosotis belongs to the family Boraginaceae. Myosotis species, like Myosotis scorpioides is an evergreen, never-ending extension to 0.3m by 0.6m at the fast rate it is not toxic when touched it causes infection. The entire plant is worn to build a medicine. Mankind used this plant for lung problems, bloody noses, etc.