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In the prothallus of a vascular cryptogam, the antherozoids and eggs mature at different times. As a result
A
there is high degree of sterility
B
one can conclude that the plant is apomictic
C
self-fertilization is prevented
D
there is no change in success rate of fertilization
Detailed Solution
Vascular cryptogams are the pteridophytes. Their gametophyte is a small, free-living, mostly photosynthetic thallus called the prothallus.
In most ferns the prothallus is monoecious; it bears both antheridia (male sex organs) and archegonia (female sex organs).
When the antherozoids and the eggs of the same prothallus mature at different times (usually the antheridia mature first, a condition called protandry), the antherozoids cannot fertilise the eggs of the same prothallus.
The eggs are then fertilised by antherozoids coming from another prothallus.
So self-fertilisation is prevented and cross-fertilisation is promoted, which brings about genetic variation.
It does not cause sterility or apomixis, and it does change the pattern of fertilisation.
Hence the result is that self-fertilization is prevented.
In most ferns the prothallus is monoecious; it bears both antheridia (male sex organs) and archegonia (female sex organs).
When the antherozoids and the eggs of the same prothallus mature at different times (usually the antheridia mature first, a condition called protandry), the antherozoids cannot fertilise the eggs of the same prothallus.
The eggs are then fertilised by antherozoids coming from another prothallus.
So self-fertilisation is prevented and cross-fertilisation is promoted, which brings about genetic variation.
It does not cause sterility or apomixis, and it does change the pattern of fertilisation.
Hence the result is that self-fertilization is prevented.