[plants]; bryophytes Flashcards
bryophytes are called
amphibians of the plant kingdom bcuz they live on land but depend upon water for sexual reproduction
examples of bryophytes
liverworts
mosses
habitats of bryophytes
damp, humid, shaded localities
they play an important role in
plant succession on bare rocks/soil
the body structure of Bryophyta
more differentiated than algae thallus like prostrate or erect attached to substratum by rhizoids lack true roots, stem, or leaves may possess root-like, stem-like, or leaf-like structures
ploidy of bryophyta
the main plant body is haploid
it produces
gametes so it is a gametophyte
sex organs in bryophytes are
multicellular
name of sex organs
antheridium(male)
archegonium(female; flask-shaped)
production by sex organs
antheridium produces bi-flagellate antherozoids
archegonium produces a single egg
process of sporophyte formation
antherozoids are released into the water and come into contact with archegonium
antherozoid fuses with the egg to form a zygote
the zygote doesn’t undergo meiosis but rather produces a multicellular body called a sporophyte
sporophyte
is not free living
attached to photosynthetic gametophyte and derives nutrition from it
process of gametophyte from the sporophyte
some cells of the sporophyte undergo meiosis and produce haploid spores
these germinate to produce gametophyte
economic importance of bryophytes
generally low economic value
provide food for herbaceous animals etc
species of Sphagnum, a moss, provides peat
and as a packing material due to its water holding capacity
ecological importance of bryophytes
mosses along with lichens were the first to colonise rocks
they decompose rocks making the substrate material suitable for the growth of higher plants
form dense mats on the ground and lessen the impact of falling rain thus preventing soil erosion
bryophytes are divided into
liverworts
mosses
habitats of liverworts
moist shady habitats, damp soil, wood, streams, etc
example of liverworts
Marchantia
the body form of liverworts
dorsiventral thallus closely appressed to the substrate
leafy members have leaf-like appendages in two rows on the stem-like structures
asexual reproduction in liverworts
fragmentation of thallus or
formation of specialised structures called gemma
gemmae
green multicellular asexual buds which develop in small receptacles called gemma cups on the thallus
the gemmae become detached from the parent body and germinate to form new individuals
sexual reproduction in liverworts
male and female sex organs are produced on the same or different thalli
the sporophyte is differentiated into a foot, seta, and capsule
these spores germinate to form free-living gametophytes
predominant stage in the life cycle of a moss
gametophytic
consisting of two stages
the two stages of the moss
protonema stage
leafy stage
protonema stage of a moss
first stage
develops directly from the spore
creeping, green, branched
frequently filamentous stage
leafy stage of moss
second stage
develops from secondary protonema as a lateral bud
upright, slender axes bearing
spirally arranged leaves
attached to the soil through multicellular and branched rhizoids
this stage bears sex organs
vegetative reproduction in mosses
fragmentation and budding in secondary protonema
sexual reproduction in mosses
the sex organs antheridia and archegonia are produced at the apex of the leafy shoots
after fertilisation, the zygote develops into a sporophyte consisting of a foot, seta and capsule
the capsule contains spores which are formed after meiosis
the sporophyte in mosses is
more elaborate than in liverworts
spore dispersal in mosses
elaborate mechanism
examples of mosses
sphagnum, funaria, polytrichum
