Question

Heteropory, i.e., formation of two types of sporres-microspores and megaspores is a characteristic feature in the life cycle of a few members of pteridophytes and all spermatophtes. Do you think heterospory has some evolutionary significance in plant kingdom?

Answer 1

Heterospory is production of spores of two different sizes and sexes and byt the sporophytes of land plants. Two types of spores are produced by heterosporic plants
Small spores are microspores which germinate into male gametophyte and large spores are macrospores which develop into female gametophyte. in evolution of plants pteridophytes are intermediate between bryophytes and gymnosperms. All bryophytes are homosporous and all gymnosperms are heteroporous. This condition is advanced as sexual dimorphism result in cross fertilisation.
Primitive or earlier pterodophtes are homosporous later pteriodophytes are heterosporous e.g. dryopteris. Pteris-homosporous Selaginella, Salvinia-heterosporous.