Question

Protonema is a characteristic feature of
A. Fern
B. Marchantia
C. Moss
D. Cycas

Answer 1

The protonema is a stage which is a creeping, green, branched and often a filamentous stage. It is the best-studied stage in the development of the Bryophyta.

Complete answer:
The predominant stage of the life cycle of a moss is the gametophytes which consist of two stages. The first stage is the protonema stage which develops directly from the spores. The second stage is the leafy stage which grows from the secondary protonema as a lateral bud. When the moss grows first from the spores it develops as a germ tube which extends and branches into a filamentous complex known as protonema. The protonema further develops into leafy gametophores which are the adult form of gametophytes in the Bryophytes. They give rise to gametophores, stem and leaf-like structure.
The protonema, which forms directly from the germinating spore, is in most mosses an extensive, branched system of multicellular filaments which are rich in chlorophyll. This stage initiates the deposition of hormones that influence the further growth of newly formed cells. The protonema of mosses is made up of two cell types chromonemata and caulonema. The chloronemata formed by germination and the caulonemata which differentiate from the chromonemata and upon which the buds are formed. The protonema helps in the formation of several moss plants.
Hence, the correct answer is C. Moss.

Note: The chromosomal complement in a moss protonema is 2n, 3n. The primary protonema is the basic part of the chain which gives out several branches or rhizoids and leaves. The secondary protonema is developed into the leafy gametophytes as part of the vegetative reproduction.