Download AG-PSB-02.441-08.6p Reproducing Plants

REPRODUCING PLANTS
CHAPTER 8
AGRISCIENCE AND
TECHNOLOGY
Modified by Georgia Agricultural Education Curriculum Office
July, 2002
August 2008
TYPES OF PLANT
REPRODUCTION
• SEXUAL REPRODUCTION - Involves using
seed to propagate plants. Flowers are important
because they contain the reproductive organs.
• ASEXUAL REPRODUCTION - Involves
reproducing plants by using vegetative parts of
the plant. Results in clones (genetically like their
parents).
August 2008
KINDS OF SEED
• MONOCOT - Plants having seed with one seed
leaf, known as a cotyledon. Examples are corn,
wheat, rice and all grasses.
• DICOT - Plants that have seed with two
cotyledon. Examples are tomatoes, beans,
petunias and carnations.
August 2008
PARTS OF A BEAN SEED
• EXTERNAL
• Seed coat - Outer covering of the seed
• Hilum - Where the seed was attached in
the pod.
• Micropyle - Tiny opening near the seed
scar where the pollen entered the ovule to
form the seed.
August 2008
PARTS OF A BEAN SEED
• INTERNAL:
• Cotyledons - Bean seed has two; contain food
for the embro.
• Radicle - Becomes the root system of the plant.
• Hypocotyl - Connects the radicle and the
cotyledons.
• Epicotyl - Forms the stem of the plant.
• Plumule - Develops the above-ground part of
the plant (embryonic leaves).
August 2008
PARTS OF A MONOCOT
SEED: CORN
• EXTERNAL:
• Seed coat - Protects the embryo.
• Seed scar - Where the corn grain was
attached to the cob.
• Silk scar - Opposite side of the grain from
the seed scar.
August 2008
PARTS OF A MONOCOT SEED
: CORN
• INTERNAL :
• Endosperm - Where the food is stored for the
embyo.
• Radicle - Becomes the root system.
• Hypocotyl - Connects the radicle with the food
source.
• Epicotyl - Forms the stem.
• Cotyledon - Does not store food; absorbs food
from the endosperm.
• Plumule - Develops into leaves.
August 2008
PARTS OF A COMPLETE
FLOWER
• Sepals - Outer part of the flower; covers the bud
and protects it as it develops.
• Petals - Located just inside the sepals; attract
insects which help with the fertilization process.
• Stamens - Male part of the flower; contains an
anther that produces pollen, or sperm.
• Pistil - Female part of the flower; contains the
stigma
August 2008
FLOWERS
• PERFECT FLOWERS - Contain the stamen and
pistil in the same flower.
• IMPERFECT FLOWERS - Flowers that lack
either the stamen or pistil.
• Exception: Monoecious plants may have both
male and female imperfect flowers on them.
Corn is an example.
August 2008
POLLINATION
• Transfer of pollen from an anther to a stigma of
a flower of the same species.
• Pollen may be moved by wind, insects, birds and
other natural means.
• Cross-pollination - When two different plants are
involved.
• Self-pollination - Involves flowers on the same
plant.
August 2008
TYPES OF FRUIT
• FLESHY FRUIT - Have large fibrous
structures surrounding the seed; apples,
pears, blackberries, oranges and grapes
are examples.
• DRY FRUIT - Fruit develops as a pod or in
a hull; beans, peas, peanuts and cotton
are examples of dry fruit. Pecans, acorns,
corn, oats, wheat, elm trees are examples
of hulls.
August 2008
GERMINATION TESTING
• When a number of seeds sprout out of a
set amount is called a germination test.
• Helps in determining the number of seeds
to plant.
• Soil is the most widely growing medium;
however greenhouses usually use
“artificial” media.
August 2008
CONDITIONS FOR SEED
GERMINATION
• MUST HAVE THE FOLLOWING:
• MOISTURE
• TEMPERATURE
• OXYGEN
August 2008
BENEFITS OF VEGETATIVE
PROPAGATION
• True traits of parents - Assures that the
new plant is identical to its parents.
• No seed - Some plants do not produce
seed: an example is seedless grapes.
August 2008
EXAMPLES OF VEGETATIVE
PROPAGATION USING
BELOW GROUND PARTS
• Potatoes are cut into sections with buds
(eyes) and planted.
• Bulbs or corms are planted; multiply and
new bulbs are pulled apart and planted
separately.
August 2008
METHODS OF ABOVE
GROUND PROPAGATION
• LAYERING - Involves getting roots to grow from
the stems of plants
• CUTTING - Involves using a short section of
plant stem for propagation.
• BUDDING - Involves taking a bud from one plant
and moving it to another.
• GRAFTING - Involves placing a section of the
stem of one plant onto another plant.
August 2008
QUALITIES OF GOOD SEED
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Purity - Contains only seed intended.
Contamination - Free of trash
Percent germination - Should be 90-100 %
Uniformity - Same size and shape
Damage - Seed coats should not be cracked
Free of disease - Healthy
Treatment - Treated to prevent disease
Reputation of grower and dealer
August 2008