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Life cycles of plant groups
Concepts tested here
- Gametophyte and sporophyte
All Questions
2012 AIPMT-MAINS 1 question
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Read the following five statements (A – E) and answer as asked next to them.
(A) In $Equisetum$ the female gametophyte is retained on the parent sporophyte
(B) In $Ginkgo$ male gametophyte is not independent
(C) The sporophyte in $Riccia$ is more developed than that in $Polytrichum$
(D) Sexual reproduction in $Volvox$ is isogamous
(E) The spores of slime moulds lack cell walls
How many of the above statements are correct?(A) is wrong: $Equisetum$ is a homosporous pteridophyte; its spores germinate into a free-living, independent gametophyte (prothallus). The female gametophyte is retained on the sporophyte only in heterosporous forms such as $Selaginella$ and in seed plants.
(B) is correct: $Ginkgo$ is a gymnosperm; in gymnosperms the male gametophyte is highly reduced, is confined to the pollen grain and has no independent free-living existence.
(C) is wrong: the sporophyte of $Riccia$ (a liverwort) is the simplest, consisting only of a capsule, whereas the sporophyte of $Polytrichum$ (a moss) is more elaborate with foot, seta and capsule.
(D) is wrong: sexual reproduction in $Volvox$ is oogamous (a large non-motile egg and a small motile male gamete).
(E) is wrong: the spores of slime moulds possess true walls and are extremely resistant.
Only statement (B) is correct, so the number of correct statements is one.