Explain briefly the following terms with suitable examples:-

(i) protonema

(ii) antheridium

(iii) archegonium

(iv) diplontic

(v) sporophyll

(vi) isogamy

Asked by Pragya Singh | 11 months ago |  36

1 Answer

Solution :-

(i) Protonema:- It is the first stage in the life cycle of moss and is developing directly from the spore. This stage consists of creeping, green, branched, and often filamentous structures.

(ii) Antheridium :- In bryophytes and pteridophytes these are the male sex organ which is surrounded by a jacket of sterile cells. The sperm mother cells are enclosed
by antheridium, which gives rise to the male gametes.

(iii) Archegonium :- Archegonium is the female sex organ present in bryophytes, pteridophytes, and gymnosperms. Generally, in bryophytes and pteridophytes, a swollen venter and a tubular neck contain the female gamete called the egg.

(iv) Diplontic :- For the life cycles of seed-bearing plants in gymnosperms and angiosperms the term diplontic is used The diploid sporophyte is dominant, photosynthetic, and independent in seed-bearing plants. A single-celled (or a few celled) structure represents the gametophyte.

(v) Sporophyll :- The sporophytic plant body bears sporangia in pteridophytes. These sporangia are subtended by sporophylls which are leaf-like appendages.
Microsporophylls and megasporophylls are found in gymnosperms, which bear microspores and megaspores respectively.

(vi) Isogamy :-A type of sexual reproduction which involves the fusion of morphologically similar gametes is known as isogamy. This indicates that the gametes are of the same size, but perform different functions. In Spirogyra this type of reproduction is commonly observed.

Answered by Abhisek | 11 months ago

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