Question

The evidence for aquatic origin of bryophyte is (multiple correct)
A. Ciliated sperms
B. Green colour
C. Protonema thread
D. Same are still aquatic

Answer 1

Bryophytes are non-vascular land plants that are found particularly in moist and dry places. The plants belonging to bryophytes do not have complex organization and they generally preterstrady and humid places.

Complete Answer:
- Bryophytes are nonvascular plants placed in between the algae and pteridophytes. Some forms are land-inhibiting plants. Whereas some are aquatic forms that live in water. They are known as ‘Amphibians’ of the plant kingdom because they require water for the act of fertilization.
- The fusion of male and female gametes resulting in formation of zygote is called fertilization. The reproduction taking place in Bryophyte is sexual reproduction and it takes place with the help of gametes soil is known as oogamous type of reproduction. The male gametes are called antherozoids and female gametes are called archegonium.
- Archegonium is also called oospores. The male gametes are biflagellate in structure. Due to the presence of flagella, antherozoids move in the water to reach the non-metallic female gamete called archegonium. This fertilization results in the formation of spores that germinate into a thread like structure.
- The thread-like structure developed in the early stages is called protonema. It looks like a simplified strand of green algae small buds arise on the structure of protonema. Which helps in the formation of new adult gametophytes.
- Thus, the evidence for aquatic origin of bryophyte is their aquatic habitat, reproduction by the means of flagellated sperms and these are usually green in color. They give rise to spores as a result of fertilization. Which helps in development of spores which develop into protonema thread.

Therefore, from the above explanation multi correct options are (B) (C) (D).

Note: Bryophytes are descendants of algae. They do not have a well differentiated body that shows root, stem and leaves but it shows root like structure called rhizoids.