Bryophyte Life-Cycle Professor Geeta Asthana Department of Botany University of Lucknow Lucknow Disclaimer: The e-content is exclusively meant for academic purposes and for enhancing teaching and learning. Any other use for economic/commercial purpose is strictly prohibited. The users of the content shall not distribute, disseminate or share it with any one else and its use is restricted to advancement of individual knowledge. The information provided in this e-content is developed from authentic references, to the best of my knowledge Bryophyte Life-Cycle Bryophytes are autotrophic, avascular, archegoniate plants with heteromorphic alternation of generations in which the gametophyte is dominant & independent phase in the life cycle and the sporophyte is dependent phase in the life cycle and is attached to the gametophyte. Both the generations are morphologically different and alternate in the life-cycle. Alternation of Generations Hofmeister (1851) studied two Distinct Phases in the Life Cycle Gametophyte: Gamete producing Phase (Sexual Phase) Sporophyte: Spore producing Phase (Asexual Phase) Strasburger (1894) studied meiosis (Reduction Division) Gametophyte: Haploid Phase (Single set of Chromosomes) Sporophyte: Diploid Phase (Double sets of Chromosomes) Syngamy Male & Female Zygote (2n) Gametes (n) Mitotic Division Alternation Gametophyte Sporophyte Haploid phase (n) of Diploid Phase (2n) Generations Spore Germination Meiosis Spores (n) Alternation of Generations Isomorphic Alternation of Generations Morphologically Similar (Algae) Heteromorphic Alternation of Generations Morphologically Different (Bryophytes & Pteridophytes) Fertilization (Water is necessary) Antherozoids & Egg Fertilized Egg (n) (2n) Mitotic Division Sex Organs Embryo (2n) Antheridia & Archegonia Bryophyte Gametophyte Sporophyte Independent Phase (n) Life Cycle Dependent Phase (2n) Thalloid/Leafy Main Plant Body Foot, Seta & Capsule Spore Germination Capsule Spores Meiosis (n) Bryophye A MossPlant Sporophyte Gametophyte Suggested Reading: Asthana Geeta 2006. “Bryophyta”. In: e-book ‘Diversity of Microbes and Cryptogams’. NISCAIR – CSIR, New Delhi. 2006, http://nsdl.niscair.res.in/dspace. Gangulee, H.C. and A.K. Kar. 1995. College Botany Vol. II. Books Allied (P) Ltd. Calcutta. Parihar, N.S. 1959. An Introduction to Embryophyta Vol. I. Bryophyta III Edition. Central Book Depot, Allahabad. Udar, R. 1976. An Introduction to Bryophyta. Shashidhar Malviya Prakashan, Lucknow. Photograph by the Research Team, Bryology Laboratory, Department of Botany, University of Lucknow, Lucknow .