Question

Heteromorphic alternation of generations is found in
A) Spirogyra
B) Mucor
C) Selaginella
D) Pinus

Answer 1

Heteromorphic alternation of generation is seen in land plants in which the haploid gametophyte and diploid sporophyte are distinct from each other. They are different both morphologically and genetically.

Complete answer:
Let us analyze each option to find out the correct answer.

Option A: Spirogyra is an algae and it does not show alternation of generation between sporophyte and gametophyte. Hence, this is an incorrect option.
Option B: Mucor is a Fungi which usually shows haplontic life cycle. Its diploid phase is only limited to the zygote stage. Hence, this is an incorrect option.
Option C: There is alternation of generation in Selaginella which happens regularly. A diploid sporophyte produces haploid microspores and megaspores which form male and female gametophyte respectively. Male and female gametes are formed from these gametophytes which eventually fuse to give rise to a diploid oospore. A sporophyte is then formed from the diploid oocyte. Hence, this is the correct answer.
Option D: Pinus does not show heteromorphosis in alternation of generation. The sporophyte phase is a dominant one and vegetative reproduction is missing. Hence, this is an incorrect option.

Additional information:

All events like gamete production, fertilization and embryo development take place inside the sporophyte.
Male gametes are developed inside the walls of the microspore.
Megaspore develops inside the megasporangium and is never released from that.

Thus, the correct answer is option (C) Selaginella.

Note: Heteromorphosis is seen when plants show haploid gametophyte and diploid sporophyte generations. They both are conspicuous and different.All events like gamete production, fertilization and embryo development take place inside the sporophyte.