Question

The evidence for aquatic origin of Bryophyte is

• A. Ciliated sperms
• B. Green colour
• C. Protonema thread
• D. Some are still aquatic

Answer 1

Answer: (A), (C)

The correct options are
A Ciliated sperms
C Protonema thread

The Bryophytes occupy the position in between algae on one hand and the Pteridophytes on the other. With the exception of few aquatic forms they are truly land-inhabiting plants. They are found in humid and shady places. As water is indispensable for the act of fertilization, they are treated to be the amphibians of the plant kingdom. The gametophyte is highly developed and differentiated than that of a complex Alga. It is independent plant at maturity. The sexual reproduction is of oogamous type, i.e., it takes place by means of gametes. The male gametes are motile (biflagellate) and known as antherozoids; the female gametes are non-motile and known as eggs (oosphere). The water is essential for the act of fertilization. The motile ciliated antherozoids swim in the film of water and reach to the neck of an archegonium.
The spores germinate into a tiny green thread, which looks like a simple strand of green Algae. This similarity is one more clue that Bryophytes are descended from green Algae. This early threadlike stage is called the protonema. The new adult gametophytes grow from a tiny bud, that develops on the protonema.