Transcript NMHS Hortculture 1

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.

The main product of Photosynthesis is Sugar
and the Byproduct is Oxygen
 Formula:
6CO2+6H2O+672Kcal
Carbon
Light
Water
Dioxide
Energy
C6H12O6+6O2
Glucose
Oxygen
Sugar
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
The two main methods of
reproduction are sexual or asexual
Osmosis

The process by which minerals
enter the plant through cell walls.

The process by which water enters
the plant through cell walls.
Light and Moisture
Light

Photoperiodism - response of plants to different
amounts of light regarding their flowering and
reproduction cycles

Short day plants require long nights to flower.
 Example:

Poinsettia
Long day plants require short nights to flower.
 Example:
Spinach

Necessary because of photosynthesis

Not enough light causes long, slender, spindly stems

Too much light will cause plants to dry out faster

Phototropism is the tendency for plants to grow
toward a light source.
Moisture

Needed in large amounts because plant
tissues are mostly water and water
carries nutrients
 90%
of plant tissue is made of water

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
Stages of Plant Growth
1. Juvenile is when plants first start to grow
from a seed.
2. Vegetative is the second stage of growth
that begins after the plant begins
photosynthesis and actively grows leaves,
stems, and roots prior to flowering
3. Reproductive is when plants produce
flowers, seeds and fruit.
4. Dormant is when plants rest or grows very
little.
Hardiness Zones
• Plants are categorized by zones based on the
average minimum temperature
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%
Affected by seed viability, temperature
and moisture.

Rates vary depending on plant and quality
(viability) of seed.

Seed viability - the seed’s capability of
growing or developing

Affected by moisture and temperature
Seeds

Plant depth depends on the size of seeds

Plant seeds no more than 1½ times the diameter of the seed.

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

The first sets of leaves
are called cotyledons.
 Monocots
produce one
seed leaf.
 Dicots
produce two
seed leaves.

True leaves are the second
set of leaves
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
Examples of plants
started by seed

Marigold

Impatiens

Begonia

Coleus

Salvia,

Shasta daisy

Pansy
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

Herbaceous plants are soft-tissue plants.

Woody plants are plants that produce woody tissue.
Stem Cuttings

Using a small piece of stem to reproduce
plants

Using hormones and dipping in fungicides
help speed up rooting

Fungicide first to prevent Rot then a Rooting
Hormone to speed root development.

Rootone is a Rooting Hormone
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
Leaf cuttings

Using small pieces of leaves to reproduce
new plants

from herbaceous plants

vein must be cut
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 - Making an incision at the
node of a branch.
 Trench layering – Cutting a trench and
laying a branch in the trench. .
 New
plants will form at each node
along the stem
 Mound
layering – mounding the soil on
a branch
Trench Layering
Division or Separation
 Division
is cutting apart rhizomes, tubers,
runners, stolons, or suckers to get new plants
 Used
on plants that grow in clumps
 Example:
Hostas and Daylilies
 Separation
is separating natural structures of a
plant without making a cut.
 Example
Bulb and Corms
Bulbs
Grafting

Joining separate plant parts together so that
they form a union and grow together to make
one plant.

Plants must be related to each other and
normally in the same genus or family.
Approach
Graft
Wedge
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

Example of plants that can be grafted:
Sweetgum (Fruitless Sweetgum) and
Pecan
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
 Example:
Rose
Chip
Budding
How to perform T-budding
Step 2
Step 1
Step 4
Step 3
Tissue Culture or
Micropropagation

Use of Cells to produce a new plant

A sterile environment is necessary for micropropagation (biotechnology)

It is a good way to get the most plants in a short period of time.

It will give you a plant identical to the parent plant.

An example would be impatiens and many flower and vegetable plants.
Advantages of Asexual
Reproduction

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
Additional Plant Propagation
Vocabulary


Corm is an enlarged, bulb-like,
fleshy structure found at the base of
a stem.
 Usually flattened and round.
 Examples: gladiolus and crocus.
Rhizome is a creeping underground
stem, usually horizontal, that
produces roots and leaves at the
nodes.

Examples: cannas and bearded Iris.
Additional Plant
Propagation Vocabulary

Stolon is a creeping above ground stem
that grows horizontally and produces
roots and shoots at the nodes.


Tuber is a swollen, modified stem that
grows underground.


Example: strawberry.
Example: potato.
Sucker is a shoot or stem that originates
from the roots.