Bryophytes are the multicellular plants, commonly called amphibians of plant kingdom.
They are found in damp, moist and shady places.
Plant body is thallus and it attaches to substratum by root like rhizoids.
They do not have true root, stem and leaves, but possess root like, stem like, leaf like structure.
The main plant body is haploid and it produces gametes, hence it is a gametophyte.
Gametophyte is dominant, which is green and photosynthetic. Sporophyte is attached and dependent on gametophyte.
The male sex organ is antheridia, which produces the gametes called antherozoids.
The female sex organ is archegonia, which produces a single gamete egg.
The fusion of gametes takes place in the water.
Economic Importance
(i) Mosses binds to the soil, which prevents soil erosion.
(ii) Bryophyte becomes food for birds, herbaceous mammals and other animals.
(iii) Sphagnum provides peat, which is used as peat fuel.
(iv) Sphagnum is used as packing material because of their water holding capacity.
(v) Mosses along with lichens are the first organisms to colonize on rocks .They cause decomposition or weathering of rocks, which supports the growth of higher plants.
Bryophytes are classified into two groups,
(i) liverworts
(ii) mosses
Liverworts
They usually grow in moist, shady habitats.
The plant body is thalloid and dorsiventrally flattened.
Some of them have tiny leaf like appandages in two rows, on the stem like structure.
They reproduce asexually by fragmentation or by formation of specialised structures called gemmae.
Gemmae are green, multicellular, asexual buds formed on small receptacles called gemma cups.
The gammae detaches form parent plant and germinate into a new plant.
Sexual reproduction is by the formation of male and female sex organs, on either side of thallus or on same side.
Sporophyte is differentiated into foot, seta and capsule. In capsule, spores are produced by meiosis.
Ex: Riccia, Marchantia.
Mosses
The dominant stage in life cycle of mosses is gametophyte which consist of two stages.
The first stage is Protonema stage, which directly develops from spore. It is creeping, green, branched and filamentous stage.
The second stage is Leafy Stage, which develops from buds of secondary protonema. It is upright,slender and bears two rows of leaves. They attach to soil through multicellular rhizoids and produce sex organs.
Vegetative reproduction takes place by fragmentation and budding of the secondary protonema.
Sexual reproduction takes place by formation of sex organs antheridia(male) and archegonia(female), produced at the apex of the leafy shoots.
After fertilisation, zygote develops into sporophyte, consisting of foot, seta and capsule.
Spores are formed in the capsule after meiosis. The released spores from the capsule, germinate to produce gametophyte.
Ex: Funaria, Polytrichum, Sphagnum
.
They are found in damp, moist and shady places.
Plant body is thallus and it attaches to substratum by root like rhizoids.
They do not have true root, stem and leaves, but possess root like, stem like, leaf like structure.
The main plant body is haploid and it produces gametes, hence it is a gametophyte.
Gametophyte is dominant, which is green and photosynthetic. Sporophyte is attached and dependent on gametophyte.
The male sex organ is antheridia, which produces the gametes called antherozoids.
The female sex organ is archegonia, which produces a single gamete egg.
The fusion of gametes takes place in the water.
Economic Importance
(i) Mosses binds to the soil, which prevents soil erosion.
(ii) Bryophyte becomes food for birds, herbaceous mammals and other animals.
(iii) Sphagnum provides peat, which is used as peat fuel.
(iv) Sphagnum is used as packing material because of their water holding capacity.
(v) Mosses along with lichens are the first organisms to colonize on rocks .They cause decomposition or weathering of rocks, which supports the growth of higher plants.
Bryophytes are classified into two groups,
(i) liverworts
(ii) mosses
Liverworts
They usually grow in moist, shady habitats.
The plant body is thalloid and dorsiventrally flattened.
Some of them have tiny leaf like appandages in two rows, on the stem like structure.
They reproduce asexually by fragmentation or by formation of specialised structures called gemmae.
Gemmae are green, multicellular, asexual buds formed on small receptacles called gemma cups.
The gammae detaches form parent plant and germinate into a new plant.
Sexual reproduction is by the formation of male and female sex organs, on either side of thallus or on same side.
Sporophyte is differentiated into foot, seta and capsule. In capsule, spores are produced by meiosis.
Ex: Riccia, Marchantia.
Mosses
The dominant stage in life cycle of mosses is gametophyte which consist of two stages.
The first stage is Protonema stage, which directly develops from spore. It is creeping, green, branched and filamentous stage.
The second stage is Leafy Stage, which develops from buds of secondary protonema. It is upright,slender and bears two rows of leaves. They attach to soil through multicellular rhizoids and produce sex organs.
Vegetative reproduction takes place by fragmentation and budding of the secondary protonema.
Sexual reproduction takes place by formation of sex organs antheridia(male) and archegonia(female), produced at the apex of the leafy shoots.
After fertilisation, zygote develops into sporophyte, consisting of foot, seta and capsule.
Spores are formed in the capsule after meiosis. The released spores from the capsule, germinate to produce gametophyte.
Ex: Funaria, Polytrichum, Sphagnum
0 Comments