What Is Heterospory. Web heterospory is the formation of two morphologically different spores (megaspores and microspores) from the sporophytes of pteridophytes and other seed plants. The female gametophyte never outgrows the limits of the megaspore.
Web heterospory is a phenomenon in which two kinds of spores are borne by the same plant. Web heterospory, defined as the production of smaller male microspores and larger female megaspores, arose independently in all major vascular plant lineages (lycophytes, monilophytes and spermatophytes) and is considered a key innovation for terrestrial colonization (bateman & dimichele, 1994; It is defined as the production of two spores that are different in size in the same plant. There is an extreme reduction in the male gametophyte and, in most cases, it is nothing but an antheridium. The larger spore is called a megaspore which leads to forming a female gametophyte. Web heterospory is the production of spores of two different sizes and sexes by the sporophytes of land plants. The smaller one is known as microspore and the larger one is known as megaspore. The clubmosses , the ferns including the arborescent. The smaller of these, the microspore , is male and the larger megaspore is female. Petersen & burd, 2016 ).
There is an extreme reduction in the male gametophyte and, in most cases, it is nothing but an antheridium. It is defined as the production of two spores that are different in size in the same plant. Heterospory evolved during the devonian period from isospory independently in several plant groups: The heterosporous condition has been observed in many families of flowering plants, including the grasses and sedges and some conifers. Web heterospory induces a drastic reduction in the sizes of their gametophytes. Web alternation of generations, also called metagenesis or heterogenesis, in biology, the alternation of a sexual phase and an asexual phase in the life cycle of an organism. Examples of heterospory plants are selaginella, salvinia, and marsilea, etc. The microspore germinates to form the male gametophyte and the megaspore germinates to form the female gametophyte. The two phases, or generations, are often morphologically,. The larger spore is called a megaspore which leads to forming a female gametophyte. The smaller one is known as microspore and the larger one is known as megaspore.
