AP BIOLOGY

Detailed explanation-1: -Heterospory is observed in pteridophytes such as Selaginella and Salvinia. In Selaginella, microspores are formed in microsporangia and megaspores are formed in megasporangia. Heterospory is important for seed habit.

Detailed explanation-2: -All seed plants, and some spore-dispersed plants, are heterosporous (Figure 2). They produce two different types of sporangia, resulting in the small microspores (sperm-producing) that develop to become microgametophytes and larger megaspores (egg-producing) that develop to form the megagametophytes.

Detailed explanation-3: -Pinus is a heterosporous. Heterosporous refers to the presence of two types of spores on the same plant: mega and microspores, whereas homospore generates identical cells. The male gametophyte or antheridium is produced by microspores, which are minuscule spores.

Detailed explanation-4: -Heterospory is the term that defines the production of two types of spores by the sporophytes of land plants. These spores which differ in size are referred to as microspore and megaspore and are borne on the same plant. This characteristic is found in Selaginella, Isoetes, Marsilea, Salvinia etc.

Detailed explanation-5: -Selaginella is heterosporous, i.e. it produces two kinds of spores; microspores and megaspores. Spores are haploid and produced by meiosis in the spore mother cells. Spores germinate into male and female gametophytes. They are small but free-living, multicellular and photosynthetic.