4. Nonvascular plants
Composed of mosses, liverworts, and hornworts
Usually seen during the rainy season, but they
wither and die during the dry season
Capable of producing spores which can
germinate into new plants
Bryophytes
5. They have two life cycle stages: (1) the
gametophyte stage, and (2) the sporophyte
stage.
The gametophyte stage is the most dominant
stage.
Bryophytes
7. Life Cycle of
Bryophytes
When the male and female gametophytes mature,
they produce reproductive cells.
The female gametophyte will produce the egg
cells in the archegonium.
The male gametophyte will produce sperm cells in
the antheridium.
The Gametophyte Stage
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8. With the presence of rainwater, the sperms swim to
egg and fertilize it.
The zygote is now then the sporophyte.
The Gametophyte Stage
9. Life Cycle of
Bryophytes
The sporophyte is held in place through the
foot to the gametophyte.
The mother cell (2N) undergoes meiosis
when inside the capsule. This leads to the
conversion of cells into spores.
The Sporophyte Stage
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10. Life Cycle of
Bryophytes
Matured spores will be released to
the outside by means of the
peristome of the capsule. The spores
are then germinated into protonema.
The Sporophyte Stage
13. The lower forms of vascular plants such as
ferns and fern allies also produce spores like
the bryophytes
These spores are found inside the sori that
are located on the under surface of the fronds
or leaves of the ferns or in some cases, in the
strobili
The life cycle of ferns also exhibits
alternation of the gametophytic and
sporophytic generation
However, the sporophytic generation is more
dominant than the gametophytic generation
Most ferns and their relatives like the
Lycopodium and Selaginella are sporophytes
The gametes are mostly discrete
16. Asexual Reproduction
Many plants use asexual reproduction to
reproduce. This strategy eliminates the costs of
producing a bloom, attracting pollinators, and
finding a way to disperse seeds.
Because male and female gametes are not
mixed, asexual reproduction generates
genetically identical plants to the parent plant.
In certain plants, reproduction is
possible through the involvement of a
single parent plant. This process is
asexual reproduction in plants.
Budding, fragmentation, vegetative
propagation, and spore development
are examples of asexual reproduction
in plants. This method does not
necessitate the use of flowers. In stable
settings, the plants produced by
asexual reproduction thrive.
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17. In asexual reproduction, plants reproduce
through vegetative parts such as runners,
suckers, rhizomes, tubers, bulbs, and corms as
well as artificial means such as tissue culture.
Runners or stolons are long, slender stems that
grow horizontally along the surface of the soil
that helps in vegetative propagation by
developing buds for the creation of new plants.
Plants with runners or stolons are gabi,
strawberries, and water lily.
Asexual Reproduction
in Plants
18. Suckers are roots that could give rise to new
plants, developing from a bud on stems and roots
of plants and emerging from the soil near the
parent plant. Many plants that come from suckers
are bamboo, bananas, and cherries.
Rhizomes are underground horizontal stems that
are modified for storage and reproduction. Each
node of the rhizome can give rise to a new plant.
These are found in grasses, ginger, and sedges.
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19. Tubers are fleshy underground storage formations of
expanded stem sections. Because of the tiny scale
leaves with buds that sprout on the surface of a tuber, it
can propagate asexually. The buds have the potential to
grow into a new plant that is genetically similar to the
parent. Potatoes, artichokes, and yams are examples of
tubers.
20. Bulbs are roughly spherical subterranean buds with fleshy
leaves growing from short stalks. They have several other
buds that can produce new plants. Examples of bulbs are
onions, leeks, and tulips.
Corms can be found in a wide variety of plants. They don't
have the stratified scales that distinguish genuine bulbs.
Cormlets are used to reproduce, and each can be split from
the parent to make exact clones of the plant. Gladiolus,
crocus, and crocosmia are classic examples of corms.
21. The growing of plant cells, tissues, or organs on specially
formulated nutritional media is tissue culture. A single cell may
regenerate an entire plant under the appropriate conditions.
Tissue culture is regarded as a critical technology for developing
countries in the creation of disease-free, high-quality planting
material and the rapid manufacture of large numbers of
homogeneous plants.
Oil palm, banana, and tomato are some plants that have been
grown with tissue culture.
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23. In flowering plants, sexual reproduction is possible due to the presence of
reproductive organs, the pistil and stamen.
Pistil is the female reproductive organ that produces the egg cells
Stamen is the male reproductive organ that produces the sperm
cells
- The pistil is collectively called the gynoecium. It usually consists of a
single carpel or two or more carpels. The swollen portion of the pistil is
the ovary which narrows to the top into a slender style, with a sticky
stigma as its tip.
- The stamen has a slender filament and another on its apex is
collectively called, androecium. Microspores, which are produced inside
the anther, later become pollen grains or sperm cells.
The pistil, the stamen, the sepals, and the petals are the four essential
parts of the flower. Some flowers that have all floral parts are known as
[complete flowers], while others may lack one or more of these floral parts
which are known as an [incomplete flower].
Sporophyte
Gametophyte
As with lower plant forms, alternation of generation is also
exhibited among higher plant forms, particularly among
angiosperms.
Alternation of Generations:
25. POLLINATION
is the transfer of pollen from the anther to
the stigma of the flower.
FERTILIZATION
takes place inside the ovary when the nucleus of
pollen grain fuses with the nucleus of an ovule to
produce a zygote.
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26. Pollination can be classfied
into two types:
SELF- POLLINATION
1.
2. CROSS - POLLINATION
pollen from the same plant lands on the stigma of
another flower,
occur only with the same plant variety, and requires the
help of pollinators such as bees, wasps, or even the wind.
Angiosperms or flowering plants
have these evolutionary characteristics. They can make their own
seeds. They have flowers that have both the male and female
reproductive organs. And lastly, they are capable of double fertilization.
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28. the ovule contains one reproductive cell
known as the macrospore.
This cell is diploid and undergoes meiosis,
producing four haploid megaspores.
leaving only one surviving megaspore
expands and undergoes three rounds of
mitosis to produce eight haploid nuclei
initially share the same cytoplasm. and
structure is known as the embryo sac.
Three cells called antipodal cells cells form
opposite of the opening of the ovule known as
the micropyle
the egg cell and this central nucleate cell
two of these are synergids and the other is
the egg cell
LEFT PART OF THE CYCLE
29. Thus, Double fertilization involves two sperm cells: one sperm
cell fertilizes the egg cell, to form the embryo, while the other
sperm cell fertilizes the central nuclei to form the endosperm
(food source for the embryo).
a pollen grain lands on the stigma
Once landed, it begins to germinate
tube cell forms a long structure down
the style and into the ovary
generative or sperm cell travels behind
the tube cell nucleus
divides by mitosis to produce two haploid
sperm cells
pollen tube reaches the micropyle and
releases the sperm cells into the embryo sac
RIGHT PART OF THE CYCLE
