Question

Describe apospory and its factors in pteridophytes

Answer 1

Apospory is the development of 2n gametophytes, without meiosis and spores, from vegetative, or nonreproductive, cells of the sporophyte. In contrast, apogamy is the development of 1n sporophytes without gametes and syngamy from vegetative cells of the gametophyte. The 2n aposporous gametophytes and the 1n apogamous sporophytes are usually infertile under natural conditions because of disruption of cytological events. Various compensating genetic mechanisms, however, may occur to complete the life history. Parthenogenesis is the formation of a 1n embryo directly from an unfertilized egg. Apospory and apogamy occur in bryophytes, pteridophytes, and angiosperms, whereas parthenogenesis occurs in ferns and angiosperms. Apogamy is more common in pteridophytes, but apospory is more common in bryophytes.

Answer 2

Apospory and its factor

Explanation:

• Apospory is the development of gametophyte directly from sporophyte without formation of spores. It is also seen in mosses and ferns. Both apospory and apogamy are considered as the abnormalities of plant life cycle.
• They reproduce by making spores. Antheridia and archegonia are the male and the female organ respectively. Eggs in the archegonia are fertilized by the sperms produced by the antheridia to produce the zygote.  
• They grow in a wide range of  habitats such as rock crevices, deserts, mountains and in moist and shady areas.
• They have leaves, stem and roots but they do not have flowers. They have specialized leaves known as sporophylls which produce spores and have fibrous roots.
• They are vascular plants i.e. they contain xylem and phloem which helps in the transportation of water and nutrients.