Question

Which major change occured in germination of spores during evolution of seed?

• A. Endosporic to exosporic
• B. Exosporic to endosporic
• C. Direct to indirect
• D. No change

Answer 1

The correct option is B Exosporic to endosporic

Germination is the process by which a plant grows from a seed. A series of changes in the reproductive biology among the heterosporous plants led to the evolution of seed plants. In seed plants, the megaspore is retained in the megasporangium and the microspore is taken to a pollen chamber at the tip of this organ. The development and fertilization of gametophyte occur within a protected environment. A pattern that showcases evolution of seed is found among the vascular plants. In homosporous vascular plants (plants that produce only one type of spore) have exosporic gametophytesthat is, the gametophyte develops outside of the spore wall. In addition, these exosporic gametophytes are normally bisexual (produce both sperm and eggs). In heterosporous vascular plants (presence of both microspores and megaspores), development of gametophyte is endoscopic and gametophytes are unisex, producing either sperm or eggs.
Therefore, the correct answer is option B.