Introduction:
Bryophyta, commonly known as mosses, liverworts, and hornworts, represent an intriguing group of non-vascular plants that play crucial roles in various ecosystems worldwide. In this presentation, we delve into the fascinating world of Bryophyta, exploring their characteristics, ecological significance, and diverse forms.
Characteristics:
Non-Vascular Structure: Unlike vascular plants, Bryophyta lack specialized tissues for transporting water and nutrients. Instead, they rely on diffusion and osmosis for nutrient uptake.
Gametophyte Dominance: Bryophytes typically exhibit a dominant gametophyte generation, with sporophytes being smaller and dependent on the gametophyte for nutrition.
Reproductive Strategy: Bryophytes reproduce via spores, which are dispersed through various mechanisms such as wind or water. They often have specialized reproductive structures like capsules or sporangia.
Habitat Diversity: Bryophytes inhabit diverse environments, including moist forests, tundra, and aquatic habitats. They can thrive in both terrestrial and aquatic ecosystems.
Ecological Significance:
Soil Stabilization: Bryophytes play a crucial role in preventing soil erosion by anchoring themselves to the substrate and trapping sediments.
Water Retention: Mosses and other bryophytes have high water retention capabilities, contributing to moisture regulation in their surroundings and providing microhabitats for other organisms.
Carbon Sequestration: Despite their small size, bryophytes contribute significantly to carbon sequestration, particularly in peatlands, where they form extensive deposits of organic matter.
Biodiversity Support: Bryophyte mats provide habitats and food sources for various microorganisms, invertebrates, and small vertebrates, enhancing biodiversity in ecosystems.
Diversity:
Mosses (Bryophyta): Mosses are the most familiar group of bryophytes, characterized by their small, leafy structures called gametophytes. They often form dense mats on soil, rocks, or tree bark.
Liverworts (Marchantiophyta): Liverworts exhibit a diverse range of forms, including thalloid (flat) and leafy species. They are typically found in moist habitats and often have unique reproductive structures.
Hornworts (Anthocerotophyta): Hornworts are characterized by their elongated, horn-shaped sporophytes emerging from a flattened gametophyte. They are less common than mosses and liverworts but are ecologically important.
Conclusion:
Bryophyta, comprising mosses, liverworts, and hornworts, are essential components of terrestrial and aquatic ecosystems worldwide. Their unique characteristics, ecological significance, and diverse forms highlight their importance in biodiversity conservation and ecosystem functioning. As we continue to explore and study Bryophyta, we gain deeper insights into the intricate web of life on Earth.
3. Bryophyta
The term Bryophyta originates from the
word ‘Bryon’ meaning mosses and
‘phyton’ meaning plants. Bryophyta
includes like mosses, hornworts, and
liverworts.
4. Bryophyta
Bryophytes are also called first
land Plants , Amphibians of
the plant kingdom
The study of bryophytes is
called bryology.
5. Bryophyta
These are small plants that grow in
shady and damp areas.
They lack vascular tissues.
They don’t produce flowers and seeds,
instead, reproduce through spores.
8. Habit
Habit : The bryophytes are very
small, green leafy or thalloid
plant body.
9. Habitat
Habitat: Bryophytes are mostly primitive
amphibian thallophytes. They generally grow
on damp, shaded, humid localities.
Vegetative structure completely adapted to
the land but during sexual reproduction
water is essential for sperms to swim
towards the female gamete for fertilization
and their development processes.
10. Plant Body
The plant body is green
gametophyte. It lacks the true
roots, stem and leaves. The
gametophytic generation is
represented by dominant, long
lived. The gametophyte is of two
types that is haploid and leafy
gametophyte.
Mosses
11. Plant Body
Thalloid gametophyte: The
thalloid gametophyte lacks the
true roots, stems and leaves. The
gametophyte is prostrate on
ground. It is attached to
substratum by delicate hair like
structure called rhizoids.
12. These rhizoids are helpful in the absorption of water and minerals.
Thalloid gametophyte bears small scale like structures on ventral surface
(Liverworts).
Leafy gametophyte: The leafy gametophyte shows roots like rhizoids,
foliose with stem like axis and leaf like appendages(Mosses).
13. Life Cycle of Bryophyte
The life cycle of bryophytes
is haplodiplontic.
The haplo-diplontic life cycle involves
the alternation of generations between
a haploid gametophyte and a diploid
sporophyte.
14. Reproduction in bryophytes
Bryophytes reproduces by vegetatively and sexually.
Vegetative reproduction: It takes place by the fragmentation ,
adventitious branches, tubers (Riccia) gemma bodies (Marchantia).
Sexual reproduction: The sexual reproduction in bryophytes is of
oogamous type.· The male sex organ is called antheridium and
female sex organ is known as archegonium.
15. The male sex organ antheridium is a
multicellular and Jacketed.
Sperms are produced in antheridium
and egg is produced in archegonium.
Sperms are always biflagellate
Sex Organ
16. The female sex organ archegonium is
multicellular, flask shaped body.
They have swollen base portion called
venter and narrow distal portion known as
neck.
The neck portion shows 4-6 neck canal cells.
The venter contains nonmotile large female
gamate called egg or oospore. 4-6 venter
canal cells.
Sex Organ
17. Fertilization
Water is essential for Fertilization.
Archegonium has six vertical rows of neck
cells.
Antherozoids are released into water and
come in contact with archegonium.
Egg (n) + Antherozoid (n) = Zygote (2n)
18. Fertilization
Zygotes(2n) does not undergo resting period
and divides by mitotic division to from
multicellular embryo that develop into a
sporophytes
Th sporophyte is mostly divided into foot , seta
and capsule
Spores germinate to produce gametophyte.
19. Spore Germination
Spore germination and protonema: In
favorable conditions each haploid spore
germinate to give rise to gametophyte
plant either directly (thalloid) or
indirectly as bud from protonema
(Mosses).
