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 Cells

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

– 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

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

Review Assignment

749689963