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Question
Explain briefly the following terms with suitable examples :
(i) Protonema (ii) Antheridium (iii) Archegonium (iv) Syngamy (v) Sporophyll (vi) Isogamy.
(i) Protonema (ii) Antheridium (iii) Archegonium (iv) Syngamy (v) Sporophyll (vi) Isogamy.
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Solution
(i) Protonema : It is the Juvenile, green, autotrophic filament like haploid, independent, gametophytic stage in the life cycle of mosses. It is produced from the germination of spores and gives rise to new gametophytic plants.
(ii) Antheridium : It is multicellular, Jacketed male sex organ in bryophytes and pteridophytes. It produces sperms (antherozoids or maie gametes).
(iii) Archegonium : It is multicellular, jacketed, flask shaped female sex organ in bryophytes, pteridophytes and gymnosperms. It has a neck and swollen venter and produces a single female gamete called egg or ovum or oosphere.
(iv) Diplontic : It is a type of life cycle in which the dominant free living phase is diploid (2x). It produces haploid gametes on gametic meiosis, e.g., Fucus, Sargassum.
(v) Sporophyll : It is a leaf that bears sporangia or sori. Sporophyll may be microsporophyll or megasporophyll. Sporophylls aggregate to form cones or strobili, e.g., sporophyll of fern; micro and megasporophyll of Selaginella, Pinus; stamen and carpel of Angiosperms.
(vi) Isogamy : It is a type of sexual reproduction in which the fusing gametes are similar in structure and function, e.g., Utothrix, Chlamydomonas, Ectocarpus.
(ii) Antheridium : It is multicellular, Jacketed male sex organ in bryophytes and pteridophytes. It produces sperms (antherozoids or maie gametes).
(iii) Archegonium : It is multicellular, jacketed, flask shaped female sex organ in bryophytes, pteridophytes and gymnosperms. It has a neck and swollen venter and produces a single female gamete called egg or ovum or oosphere.
(iv) Diplontic : It is a type of life cycle in which the dominant free living phase is diploid (2x). It produces haploid gametes on gametic meiosis, e.g., Fucus, Sargassum.
(v) Sporophyll : It is a leaf that bears sporangia or sori. Sporophyll may be microsporophyll or megasporophyll. Sporophylls aggregate to form cones or strobili, e.g., sporophyll of fern; micro and megasporophyll of Selaginella, Pinus; stamen and carpel of Angiosperms.
(vi) Isogamy : It is a type of sexual reproduction in which the fusing gametes are similar in structure and function, e.g., Utothrix, Chlamydomonas, Ectocarpus.
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