Question

Explain briefly the following terms with suitable examples:
A) Protonema
B) Antheridium
C) Archegonium
D) Diplontic
E) Sporophyll
F) Isogamy

Answer 1

Hint:The juvenile gametophyte is expressed by Protonema. While the protonema develops by apical cell division, buds that develop by three-faced apical cells are induced at some stage, under the control of the phytohormone cytokine.

Complete answer:
Let us know about the following terms with an appropriate example.
i) Protonema: A protonema is a thread-like cell chain that constitutes the initial stage of the life cycle of mosses (the haploid stage). It starts as a germ tube that lengthens and develops into a filamentous complex called a protonema, which grows into a leafy gametophore, the adult type of a gametophyte of bryophytes, when a moss first develops from the spore. Ex- Physcomitrella patens

ii) Antheridium: The antheridia are considered the equivalent male organ. A haploid arrangement or organ that creates and includes male gametes (named sperm or antherozoids) is an antheridium. An androecium is considered a structure comprising one and sometimes more antheridia. 'Androecium' is sometimes used as the collective name for the flowering plants' stamens. Ex- Hornworts

iii) Archegonium: An archegonium is indeed a multicellular form or gametophyte process organ of some plants, creating the ovum or female gamete and containing it. The archegonium has a venter or long neck canal and an enlarged base. Archegonia are usually found on the surface of the thallus of the plant, but they are found in the hornworts. Ex- bryophytes

iv) Diplontic: Gametes undergo meiosis in diplontic, and the primary and autonomous process is diploid sporophyte. Gametes are haploids and are referred to as gametophytes. The sporophyte is perceptible. Ovaries and stamens comprise sporophytes in the angiosperm. Angiosperms and gymnosperms are found in it. Ex- Cladophora glomerata

v) Sporophyll: A leaf containing sporangia is a sporophyll. Sporophylls can be both megaphylls and microphylls. Sporophylls carry either megasporangia in heterosporous plants and are thus termed megasporophylls, and microsporangia, and are referred to as microsporophylls. Ex- The brown algae Alaria esculenta displays sporophylls bound at the base of the algae.

vi) Isogamy: Isogamy is a mode of sexual reproduction involving gametes of similar shape and size, which vary only in the expression of alleles in one or more regions of the mating type in general. Ex-flagellated gametes
Note:Sporophylls are not produced by any plants. Sporangia are specifically manufactured on stems. Psilotum on the terminus of a stem has been viewed as creating sporangia (fused into a synangium). Equisetum still contains strobili, although it has been described as modified stems of the structures carrying sporangia (sporangiophores). While being curved, the sporangia are perceived as terminal.