HS 201 NCSU Brian Jackson Exam 3

Light Duration

Number of continuous hours of light in a 24 hour period

Light Quantity

Number of light particles (photons) of different wavelengths (colors) that are capable of performing photosynthesis

Light Quality

Spectral distribution of the light emitted from a light source

8 effects on plant growth

1. Photosynthesis

2. Pigment Formation

3. Seed germination

4. Fall color

5. Growth habit

6. Size

7. Flowering

8. Fruiting

4 Plant Pigments

1. Carotene (orange)

2. Xanthophyll (yellow)

3. Chlorophyll (green)

4. Anthocyanin (Red)

Phototropism

Plant response to light

Auxin

Plant hormones produced in stem tip

-Aides in organ development and cell elongation

-Concentrated in shaded regions of the stem

-Helps plants grow towards the light

-Rooting hormone

-Produced at shoot tips

-Moves away from the light

Full sun (high light) area and plants that require full sun =

Growth occurs

Low light area and plant that requires high light =

No Growth; Slow death

Light Compensation Point

Rate of photosynthesis equals the rate of respiration (energy burned to maintain light)

Light Saturation Point

Amount of light beyond which no added benefit/growth is obtained

Site Selection

How much sun exposure does that area have, and what plants can survive in the area that you choose? (choosing where to plant specific plants)

Shade Leaf (5) factors

-Larger

-Thinner

-Greener

-Lower Light compensation point

-More efficient photosynthetic apparatus

Sun Leaf (5) factors

-Smaller

-Thicker

-Less Chlorophyll (Less green)

-Higher light compensation point

-Less efficient photosynthetic apparatus

Acclimatization (and the 4 environmental factors)

Slowly changing the environment's factors:

-Light

-Temperature

-Water

-Nutrition

Hardening Off (done before planting outside)

Introducing plants to a new environment slowly

-Vegetable transplants

-Houseplants

Techniques to adjust light quantity

etiolation and blanching

Etiolation

Growing plants in the partial or full absence of light

What part of a plant is missing when they are growing in the dark

Chlorophyll

Blanching

growing technique to exclude light

-Young shoots of a plant are covered to exclude light to prevent photosynthesis and the production of chlorophyll

-Causes the plant to be pale in color

What causes the odor in urine to smell like dogwater

Sulphureous compounds

Do evergreens change colors as much as deciduous trees during the fall

NO, BAKAYAROGA

Fall color is influenced by?

genetics and environment

What stimulates the onset of fall color in deciduous plants

-Decreasing day length and Decreasing Temperatures

What stimulates the formation of the abscission layer?

Decreasing temperatures and photoperiod

What slows down in a plant during fall?

-Flow of water and nutrients

-Production and flow of sugars

-Chlorophyll synthesis

What color fades in leaves as fall progresses?

Green coloration

What pigments become visible in leaves during fall?

Yellow and orange pigments

Were yellow and orange pigments always present in leaves?

Yes, they were just hidden

What causes red coloration in levaes

Daily climactic conditions and sugar accumulation in the leaves

- The right combo leads to a red pigment

Recipe for red pigmentation in leaves

-Warm sunny days

-Cool dry nights

-Sugar pool build up

-Night temperatures <45 degrees which stimulates the conversion of sugars to Anthocyanin

Which of the pigments form in the fall when climactic conditions are met

Anthocyanin

Fall climate influences...

sugar accumulation

Location influences...

climate

T/F: Microclimate Matters

True

T/F: Anthocyanin can be found in parts of the plant other than the leaves

True

Photoperiodism

A plant growth response as influenced by the duration of light and darkness in a 24 hour period

When was Photoperiodism discovered

1920

Who discovered photoperiodism (2 people)

Garner and Allard

Most prominent example of photoperiodism

Flowering

Other responses of photoperiodism

-Seed germination

-Rooting

-Abscission

Abscission

the act of cutting; the natural separation of a leaf or other part of a plant

Three categories of angiosperms regarding photoperiodism

1. Long Day Plants

2. Short Day Plants

3. Neutral Day Plants

Long Day Plants (LDP)

Plants that are stimulated to initiate flowering when the day length is longer

Short Day Plants (SDP)

Plants that are stimulated to initiate flowers when the day length is less

Neutral day plants (NDP)

Plants that simply flower at some stage of growth with no regard to the length of day or night

Photosynthesis facts

-100 billion tons of sugar produced by plants annually

-94% of dry matter in plants from photosynthesis (6% from soil)

-Only 1% of light that hits a leaf is used in photosynthesis

-Only 1% of water absorbed by plants is used in the photosynthesis reaction

Remember the equation of photosynthesis

6CO2 + 6H20 = C6H12O6 + 6O2

Plant propagation definition

Process of creating new plants from existing ones.

Sexual

Seeds

Asexual

Vegetative: Leaf, Stem, and Root

Advantages of sexual propagation

-Less technology

-Easy shipping

-Genetic diversity

1. New colors, textures, and hybrids

Advantages of asexual propagation

-No reproductive pressure

-Bigger plants faster

-Flowering faster

-Clones and nostalgia with family plants

-Mutation preservation

Controlling propagation environment

-Air

-Water

-Light

-Soil

Air

-Movement

-Gas Exchange

-Temperature

Water

-Quantity

-Frequency

-Humidity

Soil

-Nutrients

-Air and Water Capacity

-Temperature

-Support

Light

-Quantity

-Quality

-Location

Which classes produce seeds

Angiosperms and gymnosperms

How to know the depth to plant a seed

Plant it at 1.5x the diameter of the seed

Seed Selection and Info (what info the packet says)

-Culture needs

-Grow time (varies by species and cultivar)

-Sow depth

Make sure to...

plan ahead and label your seeds

Seedling conditioning

Watch for tropisms

-Phototropism

-Gravitropism

-Thigmotropism

Gravotropism

The plants knowing which way is up and down

Thigmotropism

A directional growth of a plant in response to touch.

Hardening off/Acclimating (Part 2)

-Gradual condition to prepare plants for the outside environment

-Exposure to real, unfiltered light

-Avoid transplant shock

Asexual Vegetative Propagation (Part 2)

involves Roots, Stems, and leaves

Stem cutting types

-Types

1. Herbaceous - Can be done at any time

2. Softwood - Done at new growth

3. Semi-Hardwood - Done at seasonal growth

4. Hardwood - Done at old/dormant growth

Totipotency

Cell's ability to differentiate into new tissues and become a complete fully functioning plant

- Limited species can grow from leaf cuttings

- Can cause many plants from one leaf!

Leaf sections means

no bud required!

Leaf sections means

No bud required

Root Cuttings

-Specialized propagation method of some species

-Carbohydrates stored in roots of dormant plants

Root cuttings are NOT...

Rhizomes

Grafting

Fusing a Scion and Rootstock

-Cambium tissue connection is very important for grafting

-Must be same or closely related species

Scion

Top portion develops that develops into shoots

Rootstock

Bottom portion develops roots

Grafting mutual benefits

-Disease resistance

-Cold Hardiness

-Structure and form

-Pollination technique

-The wow factor (aesthetic)

Example of a plant you graft

Dwarf Citrus

Rootstock of Dwarf Citrus

Poncirus trifoliata

-'Monstrosa' or 'Flying Dragon'

Scion of a Dwarf Citrus Plant

Citrus sinensis

-'Washington' Navel

Grafted: • Height - 3-5' • Fruit - 'Washington' Navel (Ask about later)

Simple and Tip layering

Bend flexible stem and burying it in the soil

Air Layering

Disrupt Auxin transfer mid-stem

Natural Layering

Uses Stolons and Runners

Environment needed for layering

Dark and moist (perfect for root growth)

Bonus propagation

When plants do the propagation and you just have to move them around

Division Bonus propagation

When the Crown is separated into smaller bud sections

-Rhizomes, Offsets & Pups, or Clumps

Micropropagation (Tissue culture)

-Multiplication of plants in vitro (in glass)

-Sterile conditions

-Hormone manipulation

Goals of Micropropagation

-Genetic preservation

-Viral cleansing

-Difficult-to-root species

-Dramatic increase in population

Micropropagation environment needs to be...

Sterile

Pruning

The removal of plant parts; shoots and roots

Know there are 9 reasons to prune things

Types of pruning cuts

Heading Back - reducing the entire plant size

Thinning - selectively reducing density

Types of pruning tools

-Hand Pruners

-Loppers

-Saw (hand or chain)

-Hedge Trimmers

Hand Pruners

For stems less than ~ 1/2 inch in diameter

Loppers

For stems 1/2 of an inch to 3/2 of an inch in diameter

Saw (hand or chain)

For stems greater than 3/2 of an inch in diameter

Hedge Trimmers

-For sculpting and shaping

-Or massacring plants

Hand Pruner selection (2 of the most optimal kinds of pruners)

Bypass Pruners and Anvil Pruners (Felco is the best)

Does the color of hand pruners matter?

Yes, bright colors are easier to find in a garden