Transcript Plant Processes

PLANT PROPAGATION
Propagation
• The multiplication of a kind or species.
• Reproduction of a species.
Sexual Propagation
• Propagation from seeds.
• Pollen is transferred from the anther to the stigma.
• Fertilization occurs and seeds are produced.
Germination Rates
• Percent of seeds that sprout
• 75 out of 100=75%
• Rate is affected by seed viability, temperature and
moisture.
• Rates vary depending on plant and quality of seed.
Seeds
• Plant depth depends on the size of seeds
• larger seeds are planted deeper
• water small seeds from bottom by soaking
Embryo
Seed Coat
Endosperm
Seedlings (small plants)
• Transplant when first true leaves appear
• Reduce humidity and water and make environment more
like outside to “harden off” plants
Seeds to Seedlings
Advantages of Sexual Reproduction
• Fast way to get many plants
• Easy to do
• Economical
Disadvantages of Sexual Reproduction
• Some plants, especially hybrids, do not reproduce true to
parents
• Some plants are difficult to propagate from seeds
Asexual Reproduction
• Uses growing plant parts other than seeds
• Types of asexual reproduction:
• cuttings
• layering
• division or separation
• budding
• grafting
• tissue culture
Rooting from Cuttings
• Rooting media should be about 4 inches deep
• Best time of day is early mornings because plants
have more moisture
• Types of cuttings:
• stem
• leaf
• root
Stem Cuttings
• Using a small piece of stem to reproduce plants
• using hormones and dipping in fungicides help speed
up rooting
Leaf cuttings
• Using small pieces of leaves to reproduce new plants
• from herbaceous plants
• vein must be cut
Stem Cuttings-Step 1
Gather all materials needed
Stem Cuttings-Step 2
Cut 3 to 4 inch shoot from
stem tip
Stem Cuttings-Step 3
Remove lower leaves from the
shoot
Stem Cuttings-Step 4
Dip cut surface in rooting
hormone
Stem Cuttings-Step 5
Thoroughly moisten rooting
medium
Stem Cuttings-Step 6
Stick one or more cuttings in
rooting media
Stem Cuttings-Step 7
Cover with plastic wrap or place on
a mist bench in a warm area away
from direct sunlight.
Stem Cuttings-Step 8
Once rooted, cuttings can be
separated carefully and
transplanted
Root Cuttings
• Using small pieces of roots to reproduce plants
• should be three inches apart in rooting area
Layering
• Scarring a small area of stem to produce new plants
• air layering
• trench layering
• mound layering
Trench Layering
Division or Separation
• Cutting or pulling apart plant structures for
reproduction
• bulbs
• corms
• rhizomes
• tubers
• runners
• stolons
• suckers
Bulbs
Grafting
• Joining separate plant parts together so that they form
a union and grow together to make one plant.
Wedge
Graft
Approach
Graft
Grafting Terms
• Scion-the piece of plant at the top of the graft
• Rootstock-the piece of the plant at the root or bottom of
the graft
Methods of Grafting
• If the scion and rootstock are the same size
• wedge
• splice
• whip and tongue
• approach
Methods of Grafting
• If the scion is smaller than the rootstock
• cleft
• side
• notch
• bark inlay
Budding
• A form of grafting when a bud is used
• patch budding
• T-budding
• Chip Budding
Chip
Budding
How to perform T-budding
Step 2
Step 4
Step 1
Step 3
Tissue Culture
• Using a small amount of plant tissue to grow in a sterile
environment
• The most plants in a short time
• True to parent plant
Advantages of Asexual Production
• Plants mature in a shorter time
• Budding is faster than grafting
• In trench layering, a plant forms at each node on a
covered stem
• Some plants do not produce viable seed
• New plants are the same as the parent plant
Disadvantages of Asexual Reproduction
• Some require special equipment and skills, such as
grafting
• Cuttings detach plant parts from water and nutrient source
• Some plants are patented making propagation illegal
The Uses of Biotechnology in
Horticulture
What is Biotechnology?
• The use of cells or components (parts) of cells to
produce products or processes
Methods
• Tissue culture or micropropagation
• Cloning
• Genetic Engineering
Tissue Culture
• Uses terminal shoots or leaf buds in a sterile or
aseptic environment on agar gel or other nutrientgrowing media to produce thousands of identical
plants
Cloning
• Genetically generating offspring from non-sexual tissue
Genetic Engineering
• Movement of genetic information in the form of genes
from one cell to another cell to modify or change the
genetic make-up
Benefits of Biotechnology
• Produce many identical plants in a short time
• Increase disease and insect resistance
• Increase tolerance to heat and cold
• Increase weed tolerance
Benefits of Biotechnology
• Increase tolerance to drought
• Improve environment
• Increase production
• Other genetic changes