Life cycle

• 
  

  Mitosis in plants Leads to the formation of different plant bodies - haploid and diploid
• Gametophyte

  Haploid (n)
• During the life cycle of any sexually reproducing plant, there is an alternation of generations between gamete producing haploid gametophyte and spore producing diploid sporophyte
• Different plant life cycle patterns

  • Haplontic Life cycle
  • Diplontic Life cycle
  • Haplo-diplontic life cycle
• Haplontic Life cycle

  • Sporophytic generation is represented only by the one-celled zygote
  • No free-living sporophytes
  • Meiosis in the zygote results in the formation of haploid spores
  • The haploid spores divide mitotically and form the gametophyte
  • The dominant, photosynthetic phase is the free-living gametophyte
• Diplontic Life cycle

  • The diploid sporophyte is the dominant, photosynthetic, independent phase of the plant
  • The gametophytic phase is represented by the single to few-celled haploid gametophyte
• Haplo-diplontic life cycle

  • Both phases are multicellular
  • The dominant phase is the haploid gametophyte
  • The sporophyte is short lived and partially dependent on the gametophyte
• Life cycle of ectocarpus,polysiphomia,kelps

  Haplo-diplontic
• Life cycle of Volvox,spirogyra,chlamydomonas

  Haplontic
• Life cycle of Gymnosperms, angiosperms, fucus

  Diplontic
• Sporophyte generation is represented only by the one celled zygote in

  Haplontic life cycle
• Male and female gametophyte do not have an independent free living existence in

  Angiosperm
• Diplontic 


  ●Sporophyte is dominant phase

  ●All spermatophytes exhibit diplontic life cycle

  ●Gametophyte depends on sporophyte
• All seed bearing plants follow

  Diplontic life cycle
• In Haplo-diplontic life cycle, diploid sporophyte is represented by

  Dominant ,independent, photosynthetic,vascular plant body
• Haplontic eg

  Volvox,spirogyra,chlamydomonas
• Diplontic eg

  Seed bearing plants . Gymnosperms and angiosperms. Fucus,sargassum
• Haplo diplontic eg

  Bryophytes, pteridophytes. ectocarpus,polysiphonia,kelps,fucus