Download Fruits - Indehiscent • Dry Fruits That Do Not Split at Maturity

Fruits - Indehiscent
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Dry Fruits That Do Not Split at Maturity
(Indehiscent)
  Achene
  Nut
  Grain
  Samara
  Schizocarp
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Fruits - Indehiscent
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Achene- a single-seeded fruit in which the
seed is attached to the pericarp only at its
base
The pericarp, the husk, is easily separated
from the seed.
Ex. Sunflower, dandelion
Fruits - Indehiscent
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Nut- achene variation- one seeded, dry fruit
with a hard, thick pericarp; develops with a
cup or cluster of bracts at base
Ex- acorn, chestnut, hazelnut
Fruits - Indehiscent
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Grain (caryopsis)- a dry fruit in which the
pericarp is tightly fused to the seed
Ex- corn, rice, wheat
Fruits - Indehiscent
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Samara- a dry fruit whose pericarp extends
around the seed in the form of a wing
Ex. Maple, ash
Fruits - Indehiscent
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Schizocarp- a twin fruit that separates at
maturity into two one-seeded fruitlets
Ex- parsley, carrot, dill
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
Ex- raspberries, strawberries
Fruit
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Multiple Fruit- derived from several to many
individual flowers in a single inflorescence
Ex. Pineapple, fig, Osage orange, mulberries
Fruit and Seed Dispersal
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Wind Dispersal
  Small and Lightweight seeds.
  May have attachments like wings or hairs to
help give them lift.
  Example- maple, ash, dandelion
Animal Dispersal
  Seeds can pass through an animal’s
digestive tract.
  Some fruits and seeds have spines or
thorns that catch in fur or feathers.
  Oils attract ants.
Fruit and Seed Dispersal
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Water Dispersal
  Some fruits contain trapped air.
  Some have a waxy coating.
  Both means help the seed to float.
  Example- coconut
Mechanical Ejection of Seeds
  Capsules dry and split in a way that flings
the seeds far from the parent plant.
  Example witch hazel
How Seeds Form
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Pollination is the transfer of pollen from an
anther to a stigma.
This may occur by wind or pollinating insects,
birds or other animals.
Wind pollinated flowers usually lack showy
floral parts and nectar since they don’t need
to attract a pollinator.
Their non-showy flowers, however, do
produce a lot of pollen to increase the
likelihood that a pollen grain will land on a
receptive stigma.
Corn- pollinated by wind
How Seeds Form
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Brightly colored
flowers, those with
distinct markings or
patterns on petals,
containing
fragrance or
nectar, are most
likely pollinated by
insects, birds, or
other animals.
Birds, Butterflies, and Bats
How Seeds Form
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The surface of the stigma contains a
chemical which activates the pollen, causing
it to grow a long tube down the inside of the
style to the ovules inside the ovary.
Fertilization is the union of the male sperm
nucleus from the pollen grain and the female
egg found in the ovary.
If fertilization is successful, the ovule will
develop into a seed.
How Seeds Form
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Self-pollinating plants are capable of
fertilizing themselves. That is, pollen from a
single plant unites with an egg on the same
plant.
In some plants, self-pollination may take
place before the flower even opens.
In others, complex floral structure decrease
the probability that pollen from another plant
will reach the ovule.
How Seeds Form
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Cross-pollination occurs when pollen from
one plant fertilized the ovule of a genetically
different plant.
The surface of the stigma of selfincompatible plants recognized its own pollen
and prevents it from germination, or causes
the pollen to grow so slowly that it is not
likely to reach the ovule before another
pollen grain fertilized the ovule.
How Seeds Form
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Many fruit trees require cross-pollination for
fruit development.
How Seeds Form
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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.
Germination
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Germination is the beginning or resumption
of seed growth.
  Seed must be viable.
  Some require period of dormancy.
  Scarification
-  After Ripening
  Favorable Environmental Factors
-  Imbibe water
Germination of Dicot Seeds- ex. bean
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1. The radicle begins to grow and emerges from
the seed to form the first root, called the primary
root.
2. The hypocotyl elongates, pushing its way out
of the seed and above the soil.
3. Below the soil, secondary roots begin to
branch off of the primary root.
4. When the hypocotyl emerges into the light, it
straightens out and the epicotyl becomes
visible, revealing a pair of true leaves and the
apical meristem of the plant.
5. The leaves expand and begin to do
photosynthesis.
Germination of Monocot Seed- ex. corn
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1. The radicle grows first, piercing the kernel
and growing downward into the soil to form the
primary root.
2. The primary leaf of the shoot grows upward,
pushing its way out of the kernel and the soil.
3. Once the primary leaf reaches the light, it
pushes through the coleoptile and begins to
expand.
4. Under the soil, lateral roots begin to develop
from the primary root.
5. In corn and other monocots, adventitious
roots called prop roots also develop from the
stem and push their way into the soil.
How Seeds Grow
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Viability of most seeds is significantly
extended when the seeds are stored under
conditions of low temperatures and kept dry.
  A few species produce seeds with no
period of dormancy.
-  Vivipary
How Seeds Grow
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Viviparous plants produce seeds that
germinate before they detach from the
parent.
In many mangroves, the seedling germinates
and grows under its own energy while still
attached to its parent.
Some drop into the water and are dispersed
by currents, but others develop a heavy
straight taproot that commonly penetrates
mud when the seedling drops, thereby
effectively planting the seedling.
How Seeds Grow
Poa alpina, a grass which
shows vivipary: the seeds
germinate while still
attached to the mother plant.
Red mangrove seeds germinate
while still on the parent tree.