Question

In Riccia, apical growth occurs by
A. One apical cell
B. Single pyramid like cells
C. A row of 3-5 apical cells
D. A row of 10 apical cells

Answer 1

Hint:- Riccia is in the class Marchantiales, a genus of liverworts. This species, which are not divided into root, stem and leaves, are small and thalloid. A cell that divides repeatedly to form new cells is an apical cell.

Complete solution:
Riccia, the most commonly distributed genus in the Ericaceae family, contains nearly 200 species. In honour of P, the name Riccia was given. F. Ricci, a politician from Florence. This genus, widely distributed in both tropical and temperate regions of the world, is represented by around 33 species in India.

Riccia plant body is gametophytic and fleshy, prostrate and dichotomously branched gametophytes. Repeated dichotomy results in an appearance usually similar to a rosette. Just two dichotomies in Riccia cruciata result in a cruciate shape. Each branch of the thallus is linear, obcordate, or wedge-shaped. In all terrestrial animals, the thallus is 5-7 mm long and 1.2 mm wide. Nevertheless, in R. Fluitans are 30-50 mm long and 1-2 mm thick in length.

The notch of each branch comprises a row of 3 to 5 cells. The apical development of the thallus includes these cells. Each such cell, on its dorsal and ventral sides, cuts off derivatives alternately. The segments are often cut off from the apical cell's lateral face.
The following parts of the plant form these cells:
1. The dorsal surface segments give rise to the dorsal region of chlorenchyma.
2. The ventral face segments give rise to the ventral surface area, rhizoids, and scales.
3. The epidermis and the air canals are produced by derivatives from the outer daughter cell.

So from these discussions we can conclude that the apical growth occurs by a row of 3 to 5 cells in Riccia. Therefore the correct answer is option (C).

Note:-
Rhizoids are almost absent in marine forms, but on the ventral surface, there are typically various unicellular rhizoids of two kinds. One shape is called smooth, and pegged or tuberculated rhizoids are the other type; they assist in anchorage and absorption. The interior surface of the smooth rhizoids is smooth, while there would be internal cell wall projections for the tuberculate rhizoid.