Tag: pictorial feature of plant kingdom

In bryophytes like mosses and Riccia, the gametophyte is the dominant, independent, and photosynthetic phase of the life cycle. In pteridophytes (ferns), gymnosperms (Cycas), and angiosperms, the sporophyte is the dominant phase.

The antherozoids (male gametes) of mosses are typically spirally coiled, elongated, and possess two flagella (biflagellate) at their anterior end, which help them swim through water to reach the egg.

In Riccia, true elaters are completely absent. Instead, some of the potential spore mother cells do not undergo meiosis and instead degenerate to form sterile nurse cells, which provide nutrition to the developing spores.

In Riccia, the sex organs (antheridia and archegonia) are not exposed on the surface but are deeply embedded singly in chambers on the dorsal surface of the thallus.

Mosses are characterized by a leafy gametophore with stem-like and leaf-like structures, the complete absence of true vascular tissues, and a filamentous juvenile gametophyte stage called the protonema. Therefore, all the given statements are correct.

The sporophyte (sporogonium) of Riccia is the simplest among bryophytes, consisting solely of a capsule. It completely lacks a foot and a seta.

Since the sporophyte of Riccia consists only of a capsule and lacks a stalk (seta), it remains completely embedded within the tissue of the gametophytic thallus.

Both Riccia and Marchantia (liverworts) have unicellular, unbranched rhizoids. These can be either smooth-walled or tuberculate, but they are always single-celled and do not branch.

The peristome teeth in moss capsules are hygroscopic structures that respond to changes in humidity, aiding in the gradual and effective dispersal of spores.