Question

The microsporophyll of Cycas represents a
a. Male gamete
b. Stamen
c. Pollen grain
d. Pollinium

Answer 1

A microsporophyll in non-flowering plants that bears only microsporangia is rough, leafy triangular and the lower side bears several microsporangia between 700 and 1160.

Complete answer:

Option A is incorrect. Male Cycas gametes are produced by germination of microspores borne on microsporophylls, which are multicellular, top-shaped, equal, and the largest in the plant kingdom. It is spirally coiled with thousands of tiny cilia in the anterior portion.

Option B is correct. Cycas microsporophyll accounts for a stamen. Every microsporophyll (equivalent to angiosperm stamen) is rough, leafy triangular, and on the lower (abaxial) side bears a number (700 to 1160) of microsporangia (pollen sac). Male plants in Cycas develop male cones which are clusters of microsporophylls containing microspores (pollen) each bearing microsporangia.

Option C is incorrect. Pollen-grain is the gametophyte's first cell. In situ, i.e., the microspore germinates when inside the microsporangium. These microspores asymmetrically divide into a 2-cell where there is a smaller prothallial cell and a larger antheridial cell. No more distinction is made between the prothallium cell, while the antheridial cell divides into a smaller generative cell similar to the prothallial cell and a significantly evolved one.

Option D is incorrect. A pollinium or pollinia in a plant is a coherent mass of pollen grains that is the result of only one anther but is transferred as a single unit during pollination. This is seen frequently in plants such as orchids and several dandelions species (Asclepiadoideae).

So, the correct answer is Option B.

Note: Cycas is used as a staple food in Japan, Australia, South East Asia, the southern and eastern parts of India. It is used to produce starch and alcoholic beverages. The starch is called 'sago’, extracted from its stem.