Filicophyta

PTERIDOPHYTES
TRACHEOPHYTES
•This group comprises plants that have vascular tissues
(xylem and phloem) through which water and nutrients
are transported.
•It comprises pteridophytes and spermatophytes
(gymnosperms and angiosperms).
•Fertilization becomes indipendent from water.
PTERIDOPHYTES
•They comprise the vascular cryptogams.
•Cells are organized in real tissues forming the epidermal,
conducting (or vascular) and fundamental systems.
•Plant are differentiated in a root, serving to anchor and to absorb
water and minerals from the soil, a stem, with supporting and
conducting functions, and leaves which perform photosynthesis.
•Fertilization is still linked to water since sperms, produced by
antheridia, have flagella and reach egg cell, contained in archegonia,
through rain or moisture atmosphere.
•Main divisions: Psilophyta, Lycophyta (club-mosses, 1000 species),
Sphenophyta (horsetails, 15 species), Filicophyta (ferns, 12000
species).
•They have limited pharmaceutical uses.
PTERIDOPHYTES
•Flowerless plants exhibiting an alternation of 2 distinct and dissimilar
generations.
•The first is a non-sexual, spore-bearing, sporophyte generation (dominant)
appearing as a relatively large plant, with stems containing vascular tissue that
conducts water and dissolved solutes through the plant, and usually bears the
leaves and roots. Spores are produced in sporangia that are either attached to
the leaves (as in ferns) or are on specialized scales grouped into cones (as in
horsetails and club-mosses), or in the axils of leaves on unspecialized stems (as
in Psilotum).
•The second is a sexual, gametophyte generation (indipendent), in which the
plants generally are relatively small, and without differentiation of stem,
leaves, or roots (thalloid structure). These plants bear male (antheridia) and
female (archegonia) sex organs, together or on separate plants. When the eggs
in the archegonia are fertilized by sperms from the antheridia, an embryo
results: this can grow into a new sporophyte generation.
t.s.
•xylematic vessels
(tracheids) with
thickening of
secondary wall of
various shapes.
l.s.
Types of stele
extinct groups,
club-mosses
spermatophytes
majority of pteridophytes
ferns
•Divisions of Lycophyta, Sphenophyta and Filicophyta formed large forests
during Carboniferous (360-290 millions years ago) giving rise to carbon layers.
PSILOPHYTA
•The genus Psilotum lacks roots and bears reduced leaves (microphylls) and
sporangia grouped in small cones. It shows a dichotomous branching. It lives in
tropical regions as epiphyte.
LYCOPHYTA
•Sporophyte bearing real root,
stem and leaves (microphylls)
spirally inserted along the
axes. Procumbent stem with
dichotomous branching.
Terminal sporangia forming
cones. Plants are homospory.
Tuberous gametophyte, with
gametangia on the upper side.
At medicinal level, sporophyte
is used as diuretic and laxative.
Lycopodium clavatum
SPHENOPHYTA
•Sporophyte with sterile stem divided into nodes and internodes, rich of silica.
Whorled leaves (microphylls). Terminal sporangia forming cones beared by fertile
stems that show scaly, non-photosynthetic leaves. It comprises the genus Equisetum
whose sterile stems, rich of silica, sterols, vitamins, phenolic acids and flavonoids,
are used as diuretic, remineralizing and haemostatic.
FILICOPHYTA
•Plant with large leaves (megaphylls
or fronds) forming majority of
sporophyte. Sporangia grouped on
margin or abaxial side of fronds in sori.
The large fronds allow a better
photosynthetic activity than
microphylls. They comprise ferns, the
second most abundant group of plants
(after angiosperms) in the world. Plant
usually are homospory.
FILICOPHYTA
•Fronds of ferns are usually composite: A) simple; B) pinnate; C) bipinnate.
FILICOPHYTA
•Ferns bear sporangia forming
sori on the abaxial surface within
which spores are formed; spores
are liberated on rupture of the
sporangium wall and dispersed by
wind.
•Spores are the main dispersion
units in bryophytes and
pteridophytes. In spermatophytes
they will be replaced by seeds.
FILICOPHYTA
•The type of arrangement of sori may be of taxonomic value.
Briophytes and Pteridophytes
Spermatophytes (Gymnosperms and Angiosperms)
•In the plants with homospory (bryophytes and pteridophytes),
gametophytes develop outside the spore wall (exosporic).
•In plants with heterospory (gymnosperms and angiosperms),
gametophytes develop inside the spore wall (endosporic).
All tissues of
pteridophytes are
originated by
primary meristems.
tracheids
•Vascular bundle of a fern with xylem (composed
only of tracheids) surrounded by phloem.
Gametophyte of
Trichomanes
Gametophyte ofVittaria
Pharmaceutical importance of
Pteridophytes
•The stem of pteridophytes appear as a hypogeous, swollen,
horizontal rhizome storing nutrients and active compounds.
•All divisions comprise medicinal plants, although not as much
as angiosperms.
Life cycle of a vascular plant: sporophyte
is the dominant generation
Life cycle of a fern