Priyanti, Subject Matter Expert at Edumarz
Solution: Protonema: A protonema is the earliest stage in the development of the gametophyte in the life cycle of mosses (a bryophyte). It is a thread-like, filamentous, autonomous complex representing the juvenile gametophyte of mosses and consists of a chain of haploid cells. Protonema is formed by the lengthening and branching of germ tube that is formed by spores of moss.
Antheridium: An antheridium is the male reproductive organ of lower plants that produce male gametes (called antherozoids) and contains them. It is a sac-like structure covered by a one-cell thick layer of sterile cells and enclosing spermatogenous tissue, which give rise to spermatids by mitotic division. Antheridia is found in algae, bryophytes and some ferns.
Archegonium: An archegonium is the female reproductive organ of some non-flowering plants that produce female gametes or ovum. It is a flask-shaped structure surrounded by layers of cells and has a long neck canal and a swollen base. The cells in the neck canal dissolve as sperm passes through, and the base of archegonium contains the egg. It is observed in non-flowering plants such as gymnosperms.
Diplontic: Diplontic life cycle occurs in plants and algae as they show alternation of generation. In this case, life cycle is dominated by the diploid sporophyte stage and the haploid gametophyte stage is minimum. Gametic meiosis is observed predominantly in this stage.
Sporophyll: A sporophyll is defined as a leaf that bears sporangia. For heterosporous plants, male sporophylls are called microsporophylls and female sporophylls are called megasporophylls. Examples include ferns, Cycads and Ginkgo.
Isogamy: Isogamy is the type of sexual reproduction resulting in the fusion of two morphologically similar gametes. Examples include algae such as Spirogyra and Ulothrix.