Explain briefly the following term with suitable example :-
(i) protonema
(ii) antheridium
(iii) archegonium
(iv) diplontic
(v) sporophyll
(vi) isogamy

Explanation

(i) Protonema. The gametophytic plant body of a moss and ferns are called protonema. They are haploid, e.g., Moss and Ferns.
(ii) Antheridium. Male sex organs of bryophytes and pteridophytes are called antheridia. Each antheridium as a body and a stalk. The body encloses antherozoids covered by jacket. e.g. Marchantia.
(iii) Archegonium. Female sex organs of bryophytes and pteridophytes are called archegonia. Each archegonium is differentiated into neck, venter and stalk. The egg is enclosed within the Venter, e.g., Marchantia.
(iv) Diplontic. It is a kind of life cycle in which the diploid sporophytic generation is dominant. The gametophytic phase is represented by the single to few called haploid gametophyte. Examples, gymnosperms and angiosperms.
(v) Sporophyll. The leaf bearing sporangia is called sporophyll, e.g., ferns.
(vi) Isogamy. It is a kind of sexual fusion in which two fusing gametes are morphologically and physiologically similar e.g., chlamydomonas.