Question

Zygotic meiosis is characteristic of
A) Chlamydomonas
B) Marchantia
C) Fucus
D) Funaria

Answer 1

Hint: In phanerogams, sporadic meiosis is present, in which sporophyte sustains meiosis to form haploid spores. zygotic meiosis is organized in the haplontic life process, in which meiosis arises in the zygote. The gametic meiosis originates in some fungi, in which meiosis occurs in the cells of diploid organisms to form haploid gametes.

Complete Answer:
To solve this question, we require to remember the three types of the life cycle of plants. In plants, three types of life cycles are present: Haplontic, Diplontic and Diplohaplontic.
(a) Haplontic: In this type of the life cycle, the prominent stage is haploid. The diploid phase is represented only by zygote. It shows zygotic meiosis in which meiosis arises in zygote just after karyogamy. As a result, a diploid cell produces haploid cells. These cells divide mitotically to generate more haploid cells. In this type of life cycle, the zygote is the only diploid cell and mitosis occurs in haploid cells. It is organized in Chlamydomonas, spirogyra, Ulothrix, Dinoflagellates and maximum of the fungi.

(b) Diplontic: In this category of the life cycle, the prominent stage is diploid. It indicates genetic meiosis in which meiosis arises in the cells of diploid individuals to form haploid gametes.
These haploid gametes combine to establish a diploid zygote. The diploid cells undergo mitosis to create diploid individuals. In this category of the life cycle, the gamete is the only cell which is haploid and mitosis arises in diploid cells. It originated in Cladophora, Acetabularia, animals and some fungi.

(c) Diplohaplontic: In this category of the life cycle, both haploid phase (gametophyte) and diploid stage (sporophyte) are present. It exhibits sporadic meiosis. The haploid gametophytes divide and form haploid gametes. These gametes link to form a diploid zygote, which on germination gives increase to the diploid sporophyte. The sporophyte undergoes meiosis and forms haploid meiospores, which on germination gives increase to a haploid gametophyte. It is found in Ulva, some fungus, pteridophytes and land plants.

In zygotic meiosis, meiotic division occurs in zygote arising in the arrangement of haploid individuals. Thallophytes have dominant gametophyte generation i.e., the presence of haploid individuals. Chlamydomonas refers to kingdom Plantae and division Thallophyta, zygotic meiosis is the characteristic aspect observed in them.

Thus, option A: Chlamydomonas is the correct answer.

Note: The components of green algae exhibit zygotic, gametic and sporic meiosis. In the life process of sexually reproducing organisms, exchanging haploid and diploid phases are present. They show alternation of generation.