Short Notes on Bryophytes – Pteridophytes – Gymnosperms microbiologystudy

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Famous Indian Bryologist: DK Singh

·   Hepaticae: Each cell in the thallus contains many chloroplasts; the
chloroplasts are without pyrenoids.

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Anthocerotae: Each cell of the thallus possesses a single large chloroplast
with a pyrenoid.

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In Moss, primary protonema is haploid and gametophytic

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diploid in moss
plant- Spore mother cell

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Elators and pseudoelators in the capsules of bryophyte are meant for Spore dispersal

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sporangia of mosses? Sporocytes undergo meiosis to produce
spores

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When moss
spore germinate they form  Protonema , then a leafy gametophyte

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The
sporophyte contains pseudoelators in Anthoceros

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Funaria:  The conducting tissues do not consists Xylem and Phloem tissues in

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class “Metzgeriidae” belongs Jungermanniopsida

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Riccia:
bryophyte, the sporophyte at maturity has reduced to the sporangia.

·       Liverworts
and mosses grow on soil, on dampy soil, on rocks, and on tree trunks and also
in water

·        
Pteridophytes and bryophytes common characters :multicellular
sex organs with sterile jacket cells

Porella-  xerophytic bryophyte

Marchantia, the liverwort is characterized by

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Female organs are known as archegonia
and are protected by the thin surrounding perichaetum

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Antheridia are enclosed by a protective
layer of cells called the perigonium

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Male gametes are produced in numerous
and multiflagellate

·        
The sporophyte
hangs down from the underside of the archegonium.

Anthoceros

·        
Bryophyte with Nostoc clony can be seen in the thallus : Anthoceros

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Pseudo-elaters are present in Anthoceros

Funaria:

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can produce an embryo during sexual
reproduction

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The spore dispersal mechanism of Funaria- 
Peristomial teeth

Sphagnum

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most primitive
water conducting structures known as hydroids are found in  Sphagnum

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Bryophyte is known for its capacity to
hold water and as a source of peat:
Sphagnum

PTERIDOLOGY

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In the
prothallus of the fern plant , The nuclei of all cells including sex organs
and gametes have monoploid number

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The
protostele of Lycopodium
species shows variations with respect to its shape and arrangement of vascular
tissue such as actinostele, plectostele, mixed protostels and plectosteles.

·        
Dehiscence
of sporangia takes place by a vertical splitting in Selaginella

Classification of Pteridophyte

·         Pteridophytes with endosporic gametophytes
will be heterosporic

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In megaphyllous
pteridophytes emergence of leaf traces leaves gaps in the stele.

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Stelar types
in Pteridophytes has leaf traces:
Dictyostele

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Telome theory of Zimmermann

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Telome concept has been used in understanding the origin and
evolution of the major groups of pteridophytes.

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Overtopping -> Reduction -> Plantation -> Syngenesis
or webbing ->Curvation.

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series led to the evolution of
megaphyllous leaves:

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Over topping – planation – syngenesis

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Gametes are prouced in Prothallus

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Vascular bundle in which xylem
surrounds phloem is termed as Amphivasal.

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Antherozoids are spirally coiled and
multi- flagellated- Psilotopsida

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Spores may be homosporous or
heterosporous – Lycopsida

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Gametophytes are exosporic and green
–  Sphenopsida

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Tree fern-Cyathea

Rhynia: 
Rhynia has apical sporangium , 
Rhynia is a single-species genus of Devonian vascular plants , Rhynia
gwynne-vaughanii was the sporophyte generation of a vascular plant.

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Haplostele,
actinostele, plectostele, medullated protostele alone are protosteles

Isoetes

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A pteridophyte with the structures,
velum and foramen.

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Prismatic tissue – Isoetes

Selaginella

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Heterospous pteridophyte

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Male gametes in Selaginella are biflagellate.

Rhynia

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Fossil pteridophyte Rhynia major
belong to Psilophytales.

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Rhynia belongs to devonian

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is a pteridophyte without the
differentiation into true leaves and roots

Salvinia

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is a rootless Pteridophyte.

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The archegonia are deeply sunk in the
apical cushion. They have a very short neck, an egg cell, a venter canal cell
and a two nucleate neck canal cell.

Equisetum

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Pteridophyte with elators

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Peltate disc is the characteristic feature of strobilus
from the pteridophyta member

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siphonostele having a single phloem
ring external to the xylem is called as ectophloic siphonostele.

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Vallecular canals
and Carinal canals are the characteristic features of Equisetum

Marsilea

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In the mature sporocarp of Marsilea, inner
parenchymatous zone cells gelatinise and form a gelatinous ring which helps
in the dehiscence of the sporocarp at maturity.

Osmunda

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The maturity of sporangia within a
sorus is varied. where, the sorus type

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is a simple i.e., all the sporangia develop
simultaneously

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Tassel –  Osmunda

Azolla

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It is an aquatic fern

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It hosts symbiotic nitrogen fixing
blue-green alga

Its vascular cylinder is siphonostelic

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Sporocarp – Azolla