Lesson 5 of 12 · 6 min
Bryophytes: amphibians of the plant kingdom
NCERT §3.2
The bus climbs into the hills. At the first stop every boulder is wrapped in a soft green cushion of moss, and Meera finds thin brown stalks rising above it, each ending in a tiny capsule.
The lesson in notes
In short
Bryophytes are the mosses and liverworts, common in moist, shaded places in the hills.
They are called the amphibians of the plant kingdom: they live on land, in soil, but need water for sexual reproduction. They matter in plant succession on bare rock and soil.
The body is more differentiated than an alga's. It is thallus-like, lying flat or standing erect, and is fixed by unicellular or multicellular rhizoids. There are no true roots, stems or leaves, only root-like, stem-like and leaf-like parts.
The main plant body is haploid and makes gametes, so it is the gametophyte. The sex organs are multicellular.
The male sex organ, the antheridium, makes biflagellate antherozoids. The female sex organ, the archegonium, is flask-shaped and makes a single egg.
Antherozoids are released into water, reach the archegonium, and one fuses with the egg to form a zygote. The zygote does not undergo meiosis at once; it grows into a multicellular sporophyte.
The sporophyte is not free-living. It stays attached to the photosynthetic gametophyte and draws food from it. Some of its cells undergo meiosis to form haploid spores, which germinate into new gametophytes.
Economic importance is small overall. Some mosses feed herbivorous mammals and birds. Sphagnum gives peat, long used as fuel, and is used as packing for sending living material because it holds water.
Mosses and lichens are the first organisms to colonise rock. They break the rock down so higher plants can grow later. Dense moss mats soften falling rain and prevent soil erosion.
Bryophytes are divided into liverworts and mosses.