Pteridophytes pteron feather phyton plant ie plants with feather like leaves These are also known as vascular cryptogams HABITAT Most of the living pteridophytes are terrestrial growing in moist and shady places ID: 794285
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Slide1
PTERIDOPHYTA
Slide2INTRODUCTION
Pteridophytes
(
pteron
= feather,
phyton
= plant, i.e. plants with feather like leaves).
These are also known as
vascular cryptogams.
Slide3HABITAT
Most
of the living
pteridophytes
are terrestrial, growing in moist and shady places.
Some members are aquatic (
Azolla
,
Marsilea
,
Salvinia
) usually occurring in permanent ponds.
A few forms are
xerophytic
like
Equisetum.
Slide4HABITAT
Marsilea
(
Aquatic
)
Equisetum
Slide5PLANT BODY
They show much variation in their form, size and habit
. They
ranges from small annual (e.g.
Azolla
) to large tree-like perennials.
The main plant body is
sporophytic
, differentiated into root, stem and leaves.
The primary roots are ephemeral and are soon replaced by adventitious roots (which develop on rhizome
).
The
stem is an underground rhizome by which ferns reproduce
vegetatively
. Some primitive ferns have tree-like stem.
Slide6PLANT BODY
The leaves are scaly (
Equisetum
), small and sessile (
e.g
Lycopodium
), or large,
petiolate
and compound (Ferns).
Leaves may be small
microphyllous
(
Lycopodium
) or large
megaphyllous
(
Pteris
). These are called fronds.
The root and stem have well developed vascular system, composed of xylem and phloem. The xylem is made up of
tracheid
and the phloem has sieve tubes only. Cambium is absent.
Slide7PLANT BODY
Slide8PLANT BODY
Slide9REPRODUCTION
Vegetative
reproduction takes place by fragmentation of rhizome, adventitious buds etc.
They reproduce by spores, produced in sporangia. The
sporsporangia
are usually borne on the ventral surface of the leaf.
Sporangia occur on the surface of leaves in cluster called
sori
.(Sing.
Sorus
) and these leaves, bearing sporangia, are known as
sporophylls
The
sporophylls
with
megasporangia
are called
megasporophylls
and with
microsporangia
are called
microsporophylls
.
Sporophylls
are either
unifromly
distributed or are aggregated into compact cones (known as
strobili
) at the apex of the stem.
In aquatic forms like
Azolla
,
Salvinia
, and
Marsilea
the sporangia are present within specialized structure called
sporocarps
.
Slide10SORUS
Slide11Slide12Slide13Slide14Slide15Psilopsida
:
Psilotum
Lycopsida
:
Lycopodium,Selaginella
Sphenopsida: Equisetum (Horse taill)
Pteropsida or Filicopsida: Pteridium, Adiantum
Slide16Ornamental value
: Because of their delicate and graceful foliage, ferns are grown as ornamental plants in gardens.
Drugs :
Rhizome and petiole of
Dryopteris
yield an
antihelminthic drug. Lycopodium is used in the treatment of rheumatism and Adiantum roots help to cure throat infection.Food :
Some are rich source of starch.Soil binding : Pteridophytes protect the soil from erosion even along hill slopes by binding the soil.Scouring : Equisetum stems are used in scouring (cleaning of utensils) and polishing of metals.Biofertilisers
: Azolla has a symbiotic association with nitrogen-fixing cyanobacterium, Anabaena. It is inoculated to paddy fields to function as a
biofertilisers
.