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Flowers, Fruits, and Seeds
Chapter 8
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Required for Reproduction or Display
Outline
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Dicots versus Monocots
Structure of Flowers
Fruits
 Fleshy
 Dry
Fruit and Seed Dispersal
Seeds
 Germination
 Longevity
Dicots versus Monocots
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Dicots (Magnoliopsida)
Two cotyledons
Flower parts in fours or
fives
Leaves with distinct
vein network
Vascular cambium
present
Vascular bundles in
ring
Pollen grain with three
apertures
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Monocots (Liliopsida)
One cotyledon
Flower parts in threes
Leaves with parallel
primary veins.
Vascular cambium
absent
Vascular bundles
scattered
Pollen grain with one
aperture
Structure of Flowers
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Each flower, which begins as an embryonic
primordium that develops into a bud, occurs
as a specialized branch at the tip of a
peduncle which may have branchlets of
pedicles.
 Pedicle swells at its tip into a small pad
(receptacle).
- Other parts of the flower are attached to
the receptacle.
Structure of Flowers
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Outermost whorl
typically consists of
three to five sepals.
 Sepals (calyx) may
be fused together.
Next whorl consists of
three to many petals
(corolla).
 Calyx and corolla
form the perianth.
Structure of Flowers
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Several to many stamens
are attached to the
receptacle around the base
of the pistil.
 Each stamen consists of
a filament with an anther
at the top.
- Pollen grains
developed and
disseminated in
anthers.
Structure of Flowers
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Pistil consists of Stigma,
Style, and Ovary.
 Superior Ovary - Calyx
and corolla are attached
to the receptacle at the
base of the ovary.
 Inferior Ovary Receptacle grows up
and around the ovary.
- Calyx and corolla
appear to be
attached at the top.
Gymnosperms flowers
Sago palm, however
not a true palm:
The generic name
comes from Greek
Koikas, and means
"a kind of palm".
About 95 species are
currently accepted in the
cycad family Cycadaceae.
Gymnosperms
flowers
Seed conesfemale strobili
Polen conesmale strobili
Pollen grains
Monocot flowers
Dicot flowers
Structure of Flowers
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Inflorescences - Group of several to
hundreds of flowers
Fruits
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Fruit is an ovary and its accessory parts that
have developed and matured.
 Usually contains seeds.
 All fruits develop from flower ovaries and
accordingly are found exclusively in
flowering plants.
Fruits
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Fruit Regions
 Exocarp - Skin
 Endocarp - Inner
boundary around
seed(s).
 Mesocarp - Fleshy
tissue between
exocarp and
endocarp.
- Three regions are
collectively called
the pericarp.
Fruits
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Fleshy Fruits
 Simple fleshy fruits develop from a flower with a
single pistil.
- Drupe - Simple fleshy fruit with a single seed
enclosed by a hard, stony endocarp, or pit.
E.g,; coconuts,apricot, peach,plum, almond
Fruits
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Berry - Usually develops from a compound ovary
and often contains more than one seed. Three
types of berries:
 True berry is a fruit with a thin skin and a
relatively soft pericarp.E.g.;tomatoes, grapes,
peppers, eggplants, blueberries, cranberries,
pomegrantes.
Fruits
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Pepos - Relatively
thick rinds
(Pumpkins).
Fruits
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Hesperidium – Berry
with a leathery skin
(citrus family)
Fruits
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Pomes - Bulk of flesh comes from enlarged floral
tube or receptacle that grows up around the ovary.
(Apples)
–Acessory fruits: Fruits developed from more than
an ovary alone i.e. Pomes, pepos and some
berries
Fruits
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Aggregate Fruits
 Derived from a single flower with several to
many pistils.
- Individual pistils mature as a clustered
unit on a single receptacle
 Raspberries, Strawberries.
Aggregate fruits/Raspberries, blackberries
Aggregate fruits/Raspberries, blackberries
Individual pistils
Fruits
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Multiple Fruits
 Derived from several to many individual
flowers in a single inflorescence.
- Pineapples, Figs, Mulberries
Multiple fruits/Pineapples, figs
Fruits
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Dry Fruits That Split at Maturity (Dehiscent)
 Follicle - Splits along one side or seam
(Milkweed).
 Legume - Splits along two sides or seams
(Beans, peas,garbanzo beans, lentils,carob,
peanuts!).
 Silique - Splits along two sides or seams, but
seeds are borne on central partition, exposed
when the two halves separate (Cabbage,
broccoli).
 Capsules - Consist of at least two carpels, and
split in a variety of ways (Poppies, Lilies).
Follicles-Milkweed)
Silicles-Lunaria (Dollar plant)
Capsule-Orchid
Fruits
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Dry Fruits That Do Not
Split at Maturity
(Indehiscent)
 Achene (Sunflower)
 Nut (filberts=Hazelnut)
 Grain (Poaceae fam.)
 Samara( ashes, elms)
 Schizocarp (parsley,
carrots)
Fruits
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Dry Fruits That Do Not
Split at Maturity
(Indehiscent)
 Schizocarp: Twin
fruit (parsley,
carrots, anis, dill).
Upon drying twin
fruits break into two
one-seeded
segments called
mericarps
Fruit and Seed Dispersal
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Wind Dispersal
 Small and Lightweight
seeds.
Animal Dispersal
 Seeds pass through
digestive tract.
 Fruits and seeds catch in
fur or feathers.
 Oils attract ants.
Water Dispersal
 Some fruits contain
trapped air.
Mechanical Ejection of Seeds
Seed dispersal
Pine
Life
Cycle
Seeds
Embryo shoot: Plumule
Embryo root: radicle
SEED GERMINATION (DICOTS)
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Ovule-ovary
attachment point
Structure
 Cotyledons - Food
storage organs
that function as
first seed leaves.
 Plumule - Embryo
shoot.
 Epicotyl - Stem
above cotyledon.
 Hypocotyl - Stem
below attachment
point.
 Radicle - Stem tip
developing into a
root.
SEED GERMINATION (MONOCOTS)
Germination
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Germination is the beginning or resumption of seed growth.
 Seed must be viable.
- Some require a period of dormancy.To break the
dormancy artificial techniques might be used such as:
- Scarification: Reduce thickness of the coat
- After Ripening: Remove inhibitors
- Stratification: Cold requirement mimic
 Favorable Environmental Factors
- Imbibe water
- Temperature: Above freezing but below 45
- Light: Required in some (lettuce) but unwanted in
others (California poppy)
Longevity
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Viability of most seeds is significantly extended when the seeds are
stored under conditions of low temperatures and kept dry.
Aquatic lotus-1000 years
- Arctic tundra lupine-10 000 years
- Willow,orchids, cottonwood and tea-viable for only a few days
- Cantoloupe, squash, cucumber- several years
- Onion, leek- 2-3 years
- Wheat with proper storage:30 years with 30 % viability
1879-William J. Beal- Experiment with 1000 seeds from 20 species of
weeds
- every 5 years, after 1920 every 10 years
- In 1884 –most seeds of weeds germinated
- In 1960-evening primrose, curly dock, moth mullein seeds germinated
- In 1980 29 moth mullein, 1 mullein and 1 mallow seeds germinated
- Six of original boxes are remaining and scheduled to be open in 2040
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A few species produce seeds with no period of dormancy.
- Vivipary
Rhizophora mangle (Vivipary)
Review
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Dicots versus Monocots
Structure of Flowers
Fruits
 Fleshy
 Dry
Fruit and Seed Dispersal
Seeds
 Germination
 Longevity
Copyright © McGraw-Hill Companies Permission Required for Reproduction or Display
Oriental Sacred Lotus/ Nelumbo nucifera