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Plant Growth and Development
Essential Standard 4.00: Examine factors relating to plant growth and development.
Objective 4.01
• Explain the growth process of plants
Processes of plant growth
• Photosynthesis• Respiration• Absorption• Transpiration• Translocation• Reproduction
Photosynthesis
• The food and manufacturing process in green plants that combines carbon dioxide and water in the presence of light to make sugar and oxygen.– Formula:6CO2+6H2O+672Kcal
C6H12O6+6O2
Carbon Dioxide
Water Light Energy
Glucose Sugar
Oxygen
Respiration
• The process through which plant leaves, stems and roots consume oxygen and give off carbon dioxide.
• Plants produce much more oxygen through photosynthesis than they use through respiration.
Absorption
• The process by which plant roots take in water and air
Transpiration
• The process by which plants lose water from leaves and stems through evaporation
Translocation
• The process by which food and nutrients are moved within a plant from one plant part to another
Reproduction
• The plant process that increases plant numbers– usually by seeds
Stages of Plant Growth
• Juvenile-when a plant first starts to grow from a seed
• Reproductive-when a plant produces flowers, seeds and fruits
• Dormant-when a plant rests or grows very little, if any
Plant Cells
• Basic unit of growth• A nucleus and a mass of
protoplasm contained within a plasma membrane
Parts of a Plant Cell
• Nucleus– location of plant’s genetic and
hereditary make-up
• Protoplasm– the living matter of the cell
• Plasma Membrane– surrounds protoplasm and allows for
exchange of nutrients and gases into and out of cell
Parts of a Plant Cell
• Cell Wall– rigid and provides support for the cell
and thus the whole plant
Parts of a Plant Cell
• Other Structures– Chloroplasts– Vacuole– Plastids– Mitochondrion
Parts of a Plant Cell
Plant tissue
• A group of cells with similar origin and function
• Classified according to their origin, structure and physiology
• Structure of permanent tissue– simple-usually one type of cell– complex-several types of cells
Tissue origin and function
• Meristematic-near tip of stems and roots where cell division and enlargement occur
• Vascular cambium-increase growth in diameter of stems
Simple Tissues
• Epidermal-one-cell thick, outer layer, protects and prevents water loss
• Sclerenchyma-have thickened cell walls and contain fibers to give strength and support to plant structures
Other tissues
• Collenchyma-have thick cell walls that strengthen and support plant structures
• Parenchyma-fleshy part of plant that stores water and nutrients
Phases of the asexual cycle• Vegetative-growth and
development of buds, roots, leaves and stems– cell elongation-stage when cells
enlarge– differentiation-stage when cells
specialize
• Reproductive or flowering-plant develops flower buds that will develop into flowers, fruits and seeds
Effects of Light, Moisture, Temperature and Nutrients
on Plants
Light
• Photoperiodism-response of plants to different amounts of light regarding their flowering and reproduction cycles
• Necessary because of photosynthesis
• Not enough light causes long, slender, spindly stems
• Too much light will cause plants to dry out faster
Moisture
• Needed in large amounts because plant tissues are mostly water and water carries nutrients
• Not enough water causes wilting and stunted growth
• Too much water causes small root systems and drowning which is a result of air spaces in soil being filled with water
Temperature
• Needs vary depending on type of plants
• Either too high or too low will have adverse effects
VS
Nutrients
• Essential for optimal plant conditions
• Has little effect on seed germination
Combining growth factors
• Ideal quantities and quality will give optimum plant growth
• Each has an effect on the other factors
• Unfavorable environmental conditions for plant growth causes diseases to be more severe in their damages to plants
Hardiness Zones
Hardiness Zones
• North Carolina– Zones 6 to 8
• Considers minimum temperature extremes– Zone 6
• -10 to 0 degrees F– Zone 7
• 0 to 10 degrees F• Charlotte
– Zone 8• 10 to 20 degrees F
Plant Propagation
Essential Standard 4.00: Examine factors relating to plant growth and development.
Objective 4.02
• Use sexual and asexual methods of 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
Endosperm
Seed Coat
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
• If the scion is smaller than the rootstock– cleft– side– notch– bark inlay
Methods of Grafting
Budding• A form of grafting when a bud is
used– patch budding– T-budding– Chip Budding
Chip Budding
How to perform T-budding
Step 1
Step 2
Step 3
Step 4
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 nutrient-growing 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
• Increase tolerance to drought• Improve environment• Increase production• Other genetic changes
Benefits of Biotechnology
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