Question

Protonema is
A. Haploid and is found in mosses
B. Diploid and found in live
C. Diploid and is found in pteridophytes
D. Haploid and is found in pteridophyte

Answer 1

Hint: The gametophyte form shows several developmental stages such as the spore, the protonema, and the gametophore, which produces the sex organs. The protonema is usually threadlike and is a highly branched structure but is reduced to only a few cells in most liverworts and hornworts.

Complete Answer:
- The protonema develops from the germinating spore present in most mosses; it is an extensive, threadlike structure of multicellular filaments that are high in chlorophyll. This stage begins the growth of hormones that influence the effect growth of newly developed cells.
- When particular concentrations of the hormones are reached, the branches of the protonema produce tiny buds, which in turn produce the leafy gametophore.

Now, let us find the solution from the option.
- Gametophyte is the main phase of a moss (bryophyte) life cycle, it includes two phases.
The first phase is called protonema, which produces straight from a spore.
- The second phase is the leafy phase, which generates from the secondary protonema as a small bud. It is composed of upward, slender axes carrying spirally arranged leaves linked to the soil via multicellular and threadlike rhizoids. This stage carries the sex organs.

Thus, the correct option is A. i.e. haploid and is found in mosses.

Note: Almost in all hornworts and liverworts the protonema is commonly limited to a tiny unbranched filament that quickly begins a three dimensional cell mass. This filament is high in chlorophyll and then develops an apical cell from that the gametophyte produces.