FLOWER • STYLE

- the reproductive part of a plant. - long tube-like slender stalk that connects the stigma and the
- involved in reproduction ovary
- source of food for other living organisms • OVARY
- rich source of nectar - ductless reproductive gland that holds a lot of ovules
COMPLETE AND INCOMPLETE FLOWERS - part the plant where the seed formation takes place
COMPLETE FLOWER • OVULES
- one that consists of sepals, petals, stamens and pistils - forms the seeds of flowering plants.
- vegetative part - borne in the ovary of the flower
- reproductive part STAMEN
INCOMPLETE FLOWER - male reproductive organ
- one that lacks one or more of these structures - also known as androecium
PARTS OF THE FLOWER - consists of two parts namely: anther and filaments.
4 MAJOR WHORLS • ANTHER
• Sepals - yellowish, sac-like structure, involved in producing and
• Petals storing the pollens.
• Stamen with anther and filament • FILAMENT
• Pistil/carpels with stigma, style, ovary, and ovule - slender, threadlike object, which functions by supporting the
Other parts: receptacle anther.
REPRODUCTIVE PARTS OF A FLOWER - holds the anther in position, making the pollen available for
• PISTIL dispersal by wind, insects, or birds.
o Stigma VEGETATIVE PARTS OF A FLOWER
o Style PETALS
o ovary - bright-colored part that attracts bees, insects, and birds
• STAMEN - help us to differentiate one flower from another
o anther - contain perfume
o filament • FLOWERS OF DICOTS
PISTIL - typically have four or five sepals, petals or multiples thereof
- innermost part and the female reproductive organ of a flower which • FLOWERS OF MONOCOTS
comprises three parts-stigma, style, and ovary. - floral parts typically come in threes or multiples of three
- also known as gynoecium SEPALS
• STIGMA - green-colored part beneath the petals to protect rising buds.
- topmost/receptive tip of carpels in the gynoecium of a flower

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RECEPTACLE ANDROECIUM
- sits at the top of a stalk underneath the main portion of the flower - third whorl of a flower
- often enlarged to support the weight of the flower, or the fruit when it - male reproductive part of a flower
develops. - consists of a filament which is a thread-like structure with a circular
- main function is to both connect the stalk to the flower and to support structure anther on the top
the flower. CARPELS
PEDUNCLE (STEM) - fourth whorl of a flower present in the center
- provide support for the flower when it elevates itself to attract - contains the pistil
pollinators. - comprises the ovary, style, stigma
WHORLS TYPES OF FLOWERS BASED ON THE PRESENCE OF WHORLS
- largely responsible for the radial arrangement of a flower COMPLETE FLOWERS
4 WHORLS OF A FLOWER - if the flower has all four of these key parts (petals, sepals, stamen,
CALYX carpel)
- outermost whorl of a flower • e.g., roses, tulips
- comprises sepals, and tiny leaves present at the base of the flower INCOMPLETE FLOWERS
- protect the flower whorls against mechanical injuries and - if any one of those four elements are missing
desiccation TYPES OF FLOWERS BASED ON THE PRESENCE OF
• PETALOID REPRODUCTIVE WHORLS
- colored sepals PERFECT FLOWERS
• POLYSEPALOUS - if a flower has both the stamen (male organ) and carpel (female
- sepals are free from the calyx organ) even if it lacks some of the other key parts.
• GAMOSEPALOUS • e.g., lily, cherry blossom
- sepals are united IMPERFECT FLOWERS
• CADUCOUS - if a flower has only one of the reproductive parts, either a stamen or
- sepals fall off before the flower even opens fully carpel
• DECIDUOUS • e.g., chestnut flower, begonia
- sepals fall off after fertilization I. STAMINATE FLOWER
COROLLA - flowers that only have stamens
- second whorl of a flower - also known as androecious flowers
- contains petals which serve two main functions: - male, bearing only the male parts or stamens
❖ To attract pollinators II. CARPELLATE FLOWER
❖ To protect the reproductive parts of a flower - have a gynoecium (one of more pistils) but no functional androecium
• PERIANTH (stamens)
- comprised of the calyx and corolla - female, bearing only the female parts or pistil

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 PLANT TYPES OF BASED ON THE PRESENCE OF REPRODUCTIVE • POLLEN TUBE
STRUCTURES: MONOECIOUS OR DIOECIOUS DEVELOPMENT IN - elongates along the style and penetrates the ovule in the
FLOWERING PLANTS ovary via the micropyle (an opening)
MONOECIOUS PLANTS - discharges the sperm cells into the embryo sac inside the
- have imperfect flowers, both male and female, on the same plant ovule one sperm unites with the egg to form the zygote while the
- means that some of the flowers on the same plant will only have a other sperm fuses with the polar nuclei to become the endosperm,
functioning stamen but lack carpel, while other flowers on the same plant which serves as food of the early embryo.
will have the reverse situation; functioning carpel not stamen EMBRYO DEVELOPMENT
DIOECIOUS PLANTS EMBRYOGENESIS
- have imperfect male and female flowers on separate plants - zygote divides mitotically to produce the proembryo and suspensor,
- one plant will have all-female imperfect flowers with carpel and no which anchors the proembryo and transfers nutrients from the parent plant
stamen, while another plant of the same type will have all-male imperfect to it cotyledons appear on the proembryo (monocots have only one
flowers; functioning stamen but no carpel. cotyledon whereas dicots have two) proembryo elongates into an embryo
GAMETOPHYTE MATURATION OF OVARY AND OVULE
MALE GAMETOPHYTE - ovary matures into fruit while the ovule becomes the seed. The seed
- the microsporangium in the anther contains numerous may become dormant for some time.
microsporocytes. SEED GERMINATION
- each microsporocyte will undergo meiosis to produce four haploid - transformation of seed to seedling
microspores each microspore develops into a pollen grain (containing two - seed undergoes imbibition to break dormancy nutrients stored in
sperm nuclei and one tube nucleus) the endosperm or cotyledons are digested and transferred to the growing
FEMALE GAMETOPHYTE regions of the embryo to primary meristems (procambium) develop to
- the megasporangium in the ovule contains megasporocytes. radicle emerges to plumule breaks through the soil surface.
- one megasporocyte will undergo meiosis to produce four haploid • EPIGEAL GERMINATION
megaspores three megaspores degenerate remaining megaspore divides - occurs when the cotyledon emerges above ground, thereby
mitotically three times, an embryo sac with eight haploid nuclei membranes exposing the hypocotyl of the plumule.
partition to make the embryo sac multicellular • HYPOGEAL GERMINATION
POLLINATION - occurs when the cotyledon remains below ground, thereby
- transfer of a pollen grain from the anther to the stigma concealing the hypocotyl
- may be animal-aided or wind-aided SEEDLING GROWTH TO MATURE PLANT
DOUBLE FERTILIZATION - primary meristems differentiate to become the different plant tissues
- Inside a pollen grain, there is a tube cell and generative cell. LIFE CYCLE OF FLOWERING PLANTS
• GENERATIVE CELL • HAPLOID
- divides to produce two sperm cells - having a single set of chromosomes in each cell
• TUBE CELLS • DIPLOID
- become the pollen tube. - having two sets of chromosomes in each cell, one set from each parent
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 DOUBLE
PART OF A GUMAMELA FERTILIZATION

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GAMETOGENESIS OF FLOWERING
PLANTS

LIFE CYCLE OF FLOWERING PLANTS

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 LIFE CYCLE OF FERNS
LIFE CYCLE OF MOSS

GENERALIZED LIFE CYCLE OF PLANTS JEAN BIO(T)

DEFINITION OF TERMS PISTIL/CARPEL
GAMETOPHYTE - innermost whorl of the flower
- stage of life cycle of plants that is haploid - female reproductive structure of a flower
- stage that produces gametes via mitosis; these gametes fuse to form a - bears the female sporangia (megasporangia)
zygote that develops into a sporophyte STIGMA
SPOROPHYTE - part of the pistil where the pollen grain derived from the
- stage of the life cycle of plants that is diploid microsporangium attaches during pollination
- most familiar structure in most flowering plants STYLE
- produces haploid spores by meiosis in structures called sporangia - part of the pistil that serves as the stalk of the stigma
HAPLONTIC LIFE CYCLE - leads to the ovary
- haploid stage (gametophyte) is multicellular OVARY
- the only diploid stage is the fertilized egg cell - found at the base of the pistil
HAPLODIPLONTIC LIFE CYCLE - contains one or more ovules
- includes multicellular diploid and haploid generations - eventually becomes the fruit
ANGIOSPERMS OVULE
- also known as flowering plants - contains the female sporangia or megasporangia
- group of plants that produce reproductive structures called flowers in - eventually becomes the seed
their sporophyte stages COMPLETE FLOWER
FLOWER - flower with sepals, petals, carpels, stamens
- reproductive structure in flowering plants; made up of four whorls INCOMPLETE FLOWER
SEPALS - flower that lacks one or more of the floral whorls
- outermost whorl of a flower, collectively called the calyx PERFECT FLOWER
PETALS - flower that has both carpels and stamens
- whorl inner to the sepals - a bisexual structure
- collectively called the corolla IMPERFECT FLOWER
STAMEN - flower that has only either the stamens (staminate flower) or the
- whorl inner to the petals carpels (carpellate flower)
- male reproductive structure of the flower - also known as unisexual flower
- bears the male sporangia (microsporangia) MONOECIOUS PLANT
ANTHER - plants with having perfect flowers or both staminate and carpellate
- part of the stamen that contains the microsporangia that develops into flowers on the same individual
pollen grains DICOECIOUS PLANT
FILAMENT - plants having only either the staminate or carpellate flower
- part of the stamen that serves as the stalk of the flower

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POLLINATION SEED GERMINATION
- the placement of the pollen grain from the anther to the stigma of a - process that transforms a seed into a seedling
carpel IMBIBITION
POLLEN GRAIN - the first step in seed germination
- immature male gametophyte that develops within the anthers of - absorption of water
stamens RADICLE
- derived from the microsporocytes inside the microsporangia of anthers - embryonic root that emerges from the seed
INSIDE THE MATURE POLLEN GRAIN PLUMULE
• TUBE CELL - embryonic shoot that emerges from the seed and breaks through the
- develops into the pollen tube as in enters the style and soil surface
eventually enters the micropyle of the ovule EPICOTYL
• GENERATIVE CELL - part of the plumule above the cotyledon
- divides into two sperm nuclei and traverses the pollen tube HYPOCOTYL
EMBRYO SAC - part of the plumule below the cotyledon
- the female gametophyte found inside the ovule GAMETOGONIA/GAMETOGONIUM
- derived from the megasporocyte inside the megasporangia; a mature - multicellular sex organs of plants
embryo sac contains 8 nuclei GAMETANGIA
MICROPYLE - unicellular in algae
- the opening through the integuments of the ovule that surrounds the ANTHERIA/ANTHERIDIUM
embryo sac - male gametangia
- this is where the pollen tube enters in order to reach the embryo sac ARCHEGONIA/ARCHEGONIUM
ENDOSPERM - female gametangia
- part of the mature seed that is derived from the fusion of the sperm - bearing a single egg
nucleus and the two polar nuclei of the embryo sac SPROROGENOUS CELLS
- becomes a nutritive tissue with the triploid cells that serves to store - spore-producing cells/spore mother cells that divide by meiosis to
food for the developing embryo form haploid spore
ZYGOTE
- part of the mature seed that forms as a result of the fusion of the egg
and one of the sperm nuclei
COTYLEDON
- embryonic leaf that forms inside the seed
MONOCOT
- a plant with only one cotyledon inside the seed (monocotyledonous)
DICOT
- a plant with two cotyledons inside its seed (dicotyledonous)
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 STAGES OF SEXUAL REPRODUCTION IN FLOWERING PLANTS ▪ POLLEN GRAIN
1. MEGASPOROGENESIS - two-celled structure
- leads to the formation of female gametophyte - when the pollen is mature, the anther splits open, thus
- occurs in the ovule inside the ovary releasing the pollen
• OVULE HOMOSPOROUS AND HETEROSPOROUS
- consist of a central layer called nucellus HOMOSPORY
- two outer layers of cell called integuments - the production of one of a kind of spore
- has tiny opening called micropyle which leads to the nucellus - bryophytes whisk ferns, horsetail, most club, mosses and most ferns
o MEGASPORE MOTHER CELL • SPORES
- as the ovule become larger, one of the cells of the - gives rise to gametophyte plants that produce both eggs and
nucellus differentiated into a reproductive cell sperm cells
- diploid that undergoes meiosis forming four haploid HETEROSPORY
cells called megaspores - the production of two kinds of spores (microspores and
• 3 megaspores disintegrate, leaving only one functional megaspore megaspores)
• The functional megaspore undergoes mitosis three times, giving - club mosses, certain ferns, and all seed plants
rise to 8 nuclei • MICROSPORES
o 3 antipodals - give rise to the male gametophyte that produce sperm cells
o 2 synergids • MEGASPORES
o 1 egg - give rise to female gametophyte that produce eggs
o 1 central cell with 2 polar nuclei POLLINATION
• 7-celled structure is known as embryo sac - pollen grains will have to reach the pistil of the flower of same
2. MICROSPOROGENESIS species
- formation of male gametophyte • SELF-POLLINATION
- the pollen grains - transfer of pollen grains from the anther to the stigma of the flower
• MICROSPORE MOTHER CELL in the same plant
- cells that differentiated into reproductive cells • CROSS-POLLINATION
o MICROSPORES - transfer of pollen grains from the anther to the stigma of the flower
- diploid that undergoes meiosis, forming four haploid cells in the different plant
▪ One nucleus – called the tube nucleus remains as HOW DO POLLEN GRAINS REACH THE PISTILS
the nucleus remains as the nucleus of the • AGENTS IN NATURE THAT TRANSFER POLLEN GRAINS
microspore o INSECTS (bees, butterflies, moths, beetles, flies)
▪ The other becomes surrounded by its own o BIRDS
membrane inside the microspore and forms the o BAT
generative cell o WIND
▪ This is unusual case of a cell formed within a cell
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 • ADAPTATIONS TO ATTRACT SPECIFIC TYPES OF ANIMALS LIFE CYCLE OF MOSSES
o PRODUCE HEAVY SCENTS - the green moss gametophyte bears archegonia/antheridia at the top of
o HAVE SWEET OR FRUITY FRAGRANCES the plant
o PRODUCE NECTAR • DURING FERTILIZATION
o HAVE LARGE AND ATTRACTIVELY COLORED PETALS o Sperm cell fuses with an egg in the archegonium
POLLEN GERMINATION o The zygote grows into an embryo that develops into a moss
WHAT HAPPENS AFTER THE POLLEN HAS LANDED ON THE sporophyte which attached to the gametophyte
STIGMA OF THE FLOWER? o Meiosis occurs within the capsule of the sporophyte to
• The pollen grain absorbs liquid from the stigma and germinates produce sperm
• The generative cells divide by mitosis, producing two sperms o When a spore germinates, it grows into a protonema that
(sperm nucleus) forms buds
• The tube cell (tube nucleus) guides the growth of a long cylindrical LIFE CYCLE OF FERNS
extension of the pollen called pollen tube • Fern sporophyte have roots, rhizomes, and leaves that are called
• The pollen tube lengthens until it reaches the micropyle of the ovule megaphylls
DOUBLE FERTILIZATION • Their leaves or fronds, bears the offspring in clusters called SORI
• One haploid sperm (N) fertilizes the haploid egg (N), forming the • Meiosis in sporangia produces haploid spores
diploid (2N) zygote • The fern gametophyte called prothallus, develops from the haploid
• The other sperm (1N) fertilizes the central cell (2N) containing two spore and bears both archegonia and antheridia
polar nuclei, forming the triploid endosperm (3N) MONOECIOUS VS DIOECIOUS
• Since there are two fertilization events, the process is called MONOECIOUS
double fertilization - plant species are monoecious (one house) if the male and female parts
• The zygote undergoes a series of mitotic division, producing a mass are found on the same individual plant
differentiated cells called the embryo DIOECIOUS
ALTERNATION OF GENERATIONS - plant species are dioecious (two houses) if the male and female parts
- the life cycle of angiosperms and other plants are characterized by an are found on separate plants
alternation of generations, in which haploid (n) and diploid (2n) FROM OVULE TO SEED
generations take turns producing each other • After double fertilization, the ovule will develop into a seed
• Diploid plant (sporophyte) produces haploid spores by meiosis • The seed dehydrates as it nears the end of its maturation
• These haploid spores divide by mitosis, producing gametophytes • The embryo and its food supply (cotyledons, endosperm or both)
• These small male and female haploid plants (gametophytes) are enclosed by a hard, protective seed coat
produce gametes FRUITS
SIMPLE FRUITS
- a fruit derived from a single ovary
- can be fleshy or dry
- cherry, soybean pod
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AGGREGATE FRUITS
- a fruit that results from a single flower that has several separate
carpels
- blackberries, strawberries
MULTIPLE FRUITS
- develops from a group of separate flowers tightly clustered together
SEED DORMANCY
- a seed will not germinate, even if sown in a favorable place, until a
specific environmental cue causes them to break dormancy
- increases chances that germination will occur at a time and place most
advantageous to the seedling
STAGES OF SEED GERMINATION
1. the seed absorbs water, causing it to expand and rupture its seed coat
2. the embryo resumes growth, digesting the storage materials of the
endosperm
3. the radicle emerges from the germinating seed
4. the shoot tip breaks through the soil surface

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