Question

Spore producing sori are located on the undersurface of leaves of
A. Monocot sporophytes
B. Fern sporophyte
C. Liverwort gametophyte
D. Fern gametophyte

Answer 1

Hint: Simple clusters of sporangia are commonly seen in the dominant stage of the life cycle of ferns. It is the primary phase of the fern life cycle. Some fronds at this stage bear some fertile sorus.

Complete answer:
In ferns and fungi, a sorus is a cluster of sporangia. The sorus is surrounded by an external layer in lichens and fungi. They take the form of depression in thallus in the case of some red algae. On the edge of the fertile frond in ferns, they form a brownish or yellowish mass on the underside. I

n some species of ferns, they are protected by the umbrella-like cover during the development by a scale or film of tissue known as indusium. Sori are formed on sporophyte generation, sporangia present in the sori produce haploid meiospores. Upon sporangia maturation, the indusium shrivels so that the spore release is unimpeded. Then, the sporangia bursts and releases the spores.

Particular taxa of fern can be identified based on the shape, arrangement, and location of the sori. Sori can be circular or linear. Ferns are vascular plants that neither have seeds or flowers. They first appeared in the fossil record about 360 million years ago in the middle Devonian period.

Hence, the correct answer is option B.

Note: Fronds that bear sori are known as fertile fronds. The spores are encased to form sporangia. They cluster together to form the sorus. Some are protected by indusia while some are exposed to air.