Bryophytes are known to be the oldest land plants. They are generally found in moist and shady regions. Though they grow on land but are dependent on water for sexual mode of reproduction due to which they are also known asamphibians of the plant kingdom. Body of bryophytes is haploid comprises ofthallus and rhizoids for attachment to the substratum. True stem and roots are absent in case of bryophytes. Tutorspoint offers Bryophytes Homework Help for all level students.
Reproduction in bryophytes
Plant body of bryophytes produces gametes, hence gametophyte. Male sex organ is multicellular called antheridiumwhich produces antherozoids. Female sex organ is flask shaped called archegonium which produces single egg. Antherozoids are released in water where they fuse with egg produced by archegonium resulting zygote formation. Zygote produces sporophyte which is a multicellular stage. Sporophyte is attached to gametophyte as they depend upon gametophyte for nutrition. This sporophyte produces haploid spores which germinate to produce gametophyte.
Importance of bryophytes
1. Mosses are used as food for many animals.
2. Peat of sphagnum species is used as fuel.
3. Mosses and lichens decompose rocks to help growing higher plants.
4. Mosses reduce soil erosion.
Bryophytes are subdivided into two major classes as liverworts and mosses
Liverworts are generally found in shady regions such as bark of trees, deep in woods etc. Thallus of this class isdorsiventral and well attached to substrate. Certain members of this class possess tiny leaf like appendages on stem like structur e.g. Marchantia
Reproduction in liverworts is done by both asexual and sexual means.
This kind of reproduction takes place by formation of multicellular buds called gemmae on small receptacles known asgemma cups. Gemme on separating from parent body results in new individual formation.
This mode of reproduction results in spore formation form sporophytes by meiosis which germinates giving rise to free living gametophyte.
Mosses are flower less plants that grow in shady regions. They are devoid of roots but has root like rhizoids instead for attachments. Gametophytic stage of mosses consists of two stages namely protonema stage andleafy stage.
Protonema stage is green, branched, filamentous stage and develops directly from spore. Leafy stage as bud develops from secondary protonema. They consist of straight axis with spirally leaves. This stage also bears sex organs.
Sexual reproduction involves antheridia and archegonia which are developed at the edge of shoots. Fertilization results in zygote formation which develops in sporophyte. Mosses have elaborated sporophytes and complex spore disposable mechanism than liverworts. Some examples areFunaria, Polytrichum etc.