Biology XI: 3.Plant Kingdom(2 Division Bryophyta)

Division Bryophyta Known as amphibians of plant kingdom since they live on land, but depend on water for sexual reproduction Usually occur in cool, damp, and shady areas Play an important role in plant succession on bare rocks/soils Plant body more differentiated than algae Thallus-like plant body is attached to substratum by unicellular or multicellular rhizoids. Lack true roots, stem and leaves; may possesses root-like, stem-like, and leaf-like structures  Sporophyte is dependent on gametophyte for food. Hence, it remains attached to the gametophyte. Few cells of sporophyte undergo meiosis to produce spores (haploid). Spores germinate to form gametophyte. Economic Importance Provide food for herbaceous mammals, birds, and insects Peat provided by Sphagnum is used as fuel. Sphagnum is also used as packing material in trans-shipment of living material because of their water-holding capacity. They form dense mats on the soil and hence prevent soil erosion. Mosses along with lichens form the pioneer community in land and desert succession. Classes of bryophytes Liverworts Grow in moist, shady habitats Plant body is thalloid. Thallus is dorsiventrally appressed to the substrate. Leafy members have tiny leaf-like appendages on stem-like structures Mosses Gametophyte Predominant stage Sporophyte More elaborate than liverworts Consists of foot, seta, and capsule Capsule contains spores. Spores formed by meiosis Elaborate mechanism of spore dispersalExample − Funaria, Polytrichum, and Sphagnum