Which phase is dominant in the life cycle of Pteridophytes?
LIFE CYCLE OF PTERIDOPHYTES
• The life cycle of a pteridophyte comprises of two distinct phases or generations, each of which produces the other. One phase or generation, the sporophyte, is diploid (2n) and the dominant part of the life cycle. It is the part of the life cycle in which vascular tissue is developed. The sporophyte develops sporangia within which are diploid cells called spore mother cells or sporocyte. Each spore mother cell divides by meiotic division. As a result of meiosis, spores are produced which are, therefore, haploid (n). For More Biology Doubts visit main page of Physics Wallah.
• The gametophytic generation is always small, inconspicuous and bears male and female gametes. The male gamete i.e. antherozoids are produced in large number within the antheridium. The female gamete i.e. egg is generally borne single within the archegonium. Fertilization takes place in the presence of water when an antherozoid fuses with an egg to produce a diploid zygoyte. The zygote germinates to form the new sporphyte. This generation is called sporophytic generation.
• Thus, the life cycle of a pteridophyte consists of an alternate succession of sporophytic and gametophytic generations (heteromorphic or heterologous alternation of generation).