Question

what are primary & secondary protonema? difference? explain in detail answer as quickly as possible.

Answer 1

• Primary protonema is the first stage in the life cycle of a moss, developing directly from the spore. It consists of creeping, green, branched, and often filamentous structures.
• Secondary protonema develops from any part of the adult like rhizoids, stems and leaves.

Let me explain in detail:

• The primary protonema produced as a result of spore germination breaks up into small fragments by the formation of some intercalary colourless cells. Each fragment grows into a new protonema.
• Sometimes filamentous protonema may be formed from any cell of a detached injured portion of any stem, leaf and rhizoid when surrounded by moist air. It is similar in function and behavior to primary protonema and called secondary protonema.