Question

In pteridophytes, prothallus produces _ _ _ _ _ _ _ _ _ _
(A) sporangia
(B) antheridia and archegonia
(C) vascular tissues
(D) root, stem and leaf

Answer 1

Hint: Pteridophytes are a group of prothallus producing spores. These spores are developed in sphorgia and these take part in reproduction.

Complete answer:
Pteridophytes cannot produce flowers or seeds. Pteridophytes are also referred to as cryptogams. The leaves of pteridophytes are known as fronds. In pteridophytes, prothallus produces antheridia and archegonia.

Pteridophytes are spores producing plants. These spores can be either homopterous or heterosporous. These plants have vascular tissues (xylem and phylum) that are also called as conducting tissues. Xylem helps in the transport of water and minerals from roots to different parts of the plant body. Phloem helps in the transport of food material from leaves to different plant parts.

The sporophyte bears sporangia that develop spores by meiosis and they form microspores that are haploid; these microspores germinate to give rise to gametophyte called prothallus. The male sex organs produced by prothallus in gametophyte generation is antheridia and female gamete is archaeganis.
On germination, the prothallus which is monoeciuous gives rise to anthredia which is male sex organs and archegonia which is female sex organs.

Therefore, the correct answer is option (B) antheridia and archegonia.

Note: Pteridophytes show alternation of generation i.e. sporophyte and gametophyte is the main or dominant generation of pteridophytes. There is reduction of choromos numbers to ‘n’ and possess sex organs and its connected with sexual reproduction. The haploid gametes units to form a diploid ‘2n’ nucleus. As a result of fertilization zygote is formed which germinates into embryo and devotes sporophyte.