Hort 201 Exam 4

Front 1

Sexual or Seed Propagation Advantages

Back 1

1) produces large numbers in a short period of time
2) can handle large numbers easily
3) produces hybrids

Front 2

Sexual or Seed Propagation Disadvantages

Back 2

1) some plants produce no viable seeds
2) some seeds are very difficult or slow to germinate
3) causes genetic variability (e.g. due to production of hybrids)

Front 3

totipotency

Back 3

the concept that every cell in a plant has the inherent genetic ability to
reproduce the entire plant.

Front 4

Asexual or Vegetative Propagation Advantages

Back 4

1) All off-spring are true-to-type (identical to the parent) and produce a clone .
clone - a group of plants, cultivar or variety derived from the same parent plant by asexual
(vegetative) propagation.
2) for plants that are hard or impossible to propagate from seeds
3) decrease time to flowering (esp. grafting & budding); by-passes juvenile phase

Front 5

Asexual or Vegetative Propagation Disadvantages

Back 5

1) can only propagate a few from each parent (except tissue culture).
2) requires a lot of labor

Front 6

Tissue Culture

Back 6

An asexual propagation technique where small pieces of excised tissue or individual cells are placed in sterile in vitro culture containing all the nutrients, carbohydrates and hormones needed for growth. The tissue grows rapidly and can be induced to produce large numbers of new plants. Hormones are used to cause the tissue to grow into callus masses, roots or shoots. Sometimes called micropropagation.

Front 7

pollination

Back 7

deposition of pollen on the stigma of the pistil.

Front 8

ploidy

Back 8

the number of sets of chromosomes present in the nucleus of the cell.
haploid = 1N = 1 of each chromosome
diploid = 2N = 2 of each chromosome
triploid = 3N = 3 of each chromosome
tetraploid = 4N = 4 of each chromosome

Front 9

gamete

Back 9

a haploid (1N) reproductive cell.
- the male gamete is the sperm cell with its 1N nucleus
- the female gamete is the egg cell with its 1N nucleus.

Front 10

fertilization

Back 10

the union of one male gamete (1N sperm nucleus) and one female gamete (1N egg
nucleus) to produce a zygote (2N).

Front 11

double fertilization

Back 11

union of one male gamete (1N) with one female gamete (1N) to produce a
zygote (2N), plus the union of one male gamete (1N) with two polar nuclei (1N
each) to produce an endosperm (3N); occurs in higher plants only (angiosperms).

Front 12

apomixis

Back 12

development of an embryo without fertilization; hence, it is not true sexual propagation
even though it produces a seed.

Front 13

parthenocarpy

Back 13

development of fruit without seeds.

Front 14

vivipary

Back 14

germination of seeds inside the fruit while still attached to the parent plant.

Front 15

Tissue Culture

Back 15

An asexual propagation technique where small pieces of excised tissue or individual cells are placed in sterile in vitro culture containing all the nutrients, carbohydrates and hormones needed for growth. The tissue grows rapidly and can be induced to produce large numbers of new plants. Hormones are used to cause the tissue to grow into callus masses, roots or shoots. Sometimes called micropropagation.

Front 16

pollination

Back 16

deposition of pollen on the stigma of the pistil.

Front 17

ploidy

Back 17

the number of sets of chromosomes present in the nucleus of the cell.
haploid = 1N = 1 of each chromosome
diploid = 2N = 2 of each chromosome
triploid = 3N = 3 of each chromosome
tetraploid = 4N = 4 of each chromosome

Front 18

gamete

Back 18

a haploid (1N) reproductive cell.
- the male gamete is the sperm cell with its 1N nucleus
- the female gamete is the egg cell with its 1N nucleus.

Front 19

fertilization

Back 19

the union of one male gamete (1N sperm nucleus) and one female gamete (1N egg
nucleus) to produce a zygote (2N).

Front 20

double fertilization

Back 20

union of one male gamete (1N) with one female gamete (1N) to produce a
zygote (2N), plus the union of one male gamete (1N) with two polar nuclei (1N
each) to produce an endosperm (3N); occurs in higher plants only (angiosperms).

Front 21

apomixis

Back 21

development of an embryo without fertilization; hence, it is not true sexual propagation
even though it produces a seed.

Front 22

parthenocarpy

Back 22

development of fruit without seeds.

Front 23

vivipary

Back 23

germination of seeds inside the fruit while still attached to the parent plant.

Front 24

Caused By
1) Dry Seeds:
dehydration of seed

Back 24

How Overcome?
sow in moist environment

Front 25

Caused By
Seed Coat Dormancy or
Hardseededness:
hard seed coat impermeable
to water and gases

Back 25

How Overcome?
scarification - physical or chemical abrasion of seed coat.

Front 26

Caused By
3) Embryo Rest:
low growth promoters and/or
high growth inhibitors
in embryo

Back 26

How Overcome?
stratification - cold (35-40 oF), moist storage or 4-12 weeks.

Front 27

Caused By
4) Double Dormancy:
hard seed coat plus embryo
rest

Back 27

How Overcome?
scarification then stratification

Front 28

Caused By
5) Chemical Inhibitors:
inhibitors in pericarp (fruit
wall) or testa (seed coat)

Back 28

How Overcome?
I) if fleshy, remove fleshy pericarp
(fruit wall) or testa (seed coat).
2) if pericarp or testa is dry, leach
in running water.

Front 29

Caused By
6) Immature Embryo:
underdeveloped or
rudimentary embryo

Back 29

How Overcome?
1) after ripening - store for 4-6
weeks under ambient conditions
2) warm stratification - warm moist
storage.
3) embryo culture - excise embryo
and put in tissue culture

Front 30

Caused By
7) Light Requirement
phytochrome in Pr form

Back 30

How Overcome?
I) expose to any white light
2) expose to red light
3) sow shallow or on surface

Front 31

scarification

Back 31

physical or chemical abrasion of seed coat.

Front 32

cutting

Back 32

a plant part that when removed from the parent plant and placed under theproper
environmental conditions forms adventitious roots and/or shoots.

Front 33

HOW TO MINIMIZE WATER LOSS IN CUTTINGS?

Back 33

1) Place cuttings in cool, humid area - for leafless cuttings

2) Spray cuttings with antitranspirants.

antitranspirants - chemicals that decrease transpiration by forming a film on the leaf surface or
by physiologically closing stomata.

3) Place cuttings in a humidity chamber - enclosed chamber with very high humidity.

4) Place cuttings under an intermittent mist system.

Front 34

Intermittent Mist System

Back 34

A propagation system that periodically (every 5 to 30 minutes) sprays a fine mist of water on the cuttings to keep the foliage moist and minimize water loss.

Front 35

Intermittent Mist System
Effective due to:

Back 35

a) high relative humidity
b) cooler temperature
c) allows use of higher light intensity
d) increases endogenous root promoting substances
e) may decrease disease

Front 36

HORMONES USED ON CUTTINGS
1) auxin

Back 36

stimulates adventitious root formation on stem cuttings.
- IBA (most commonly used), NAA (frequently used), 2, 4-D (less used).

Front 37

HORMONES USED ON CUTTINGS
2) cytokinin

Back 37

stimulates adventitious shoot formation on leaf or root cuttings.
- kinetin (commonly used), benzyladenine (BA) (commonly used), zeatin (seldom used),
pyranylbenzyladenine(PBA) ( used in research).

Front 38

Leaf Cuttings

Back 38

See page 86 of notes

Front 39

chimera

Back 39

a plant or plant part composed of genetically different layers

Front 40

The center of a chimera is white, the outer is green. Which layer is mutated?

Back 40

3rd layer

Front 41

layering

Back 41

a propagation technique where roots are formed prior to the stem being removed
from the parent plant.

Front 42

Sexual Life Cycle

Back 42

Front 43

Woody Dicot or Gymnosperm Cutting Layering

Back 43

Front 44

Monocot Cutting Layering

Back 44

Front 45

grafting

Back 45

the joining of separate plant parts together, such that they form a union and grow as one
plant

Front 46

scion or cion

Back 46

the upper part of the graft that becomes the shoot system of the
new plant.

Front 47

stock, rootstock or understock

Back 47

the lower part of the graft that becomes the
root system of the new plant.

Front 48

Budding

Back 48

a type of grafting where the scion is just a bud piece or small chip of wood with a bud
attached.

Front 49

Reasons for Grafting or Budding

Back 49

1) Plants cannot be propagated by other means, ex. plants in adult phase
2) Decrease time to flowering and fruiting, especially fruit and nut trees
3) Obtain desirable characteristics of rootstock, such as:
a) disease resistance
b) adapted to soils or climate in various regions
c) dwarfing
4) Change variety, topwork mature trees
5) Special forms, usually for ornamental purposes, ex. tree roses
6) Repair damage (inarching, brace graft, bridge graft)
7) Virus indexing, used for diagnosing virus diseases

Front 50

FACTORS AFFECTING SUCCESS OF GRAFTING OR BUDDING

Back 50

1) Plant type - can only graft dicots and gymnosperms; not monocots (lack a cambium)
2) Plant Relationship - within species is most successful
3) Incompatibility - sometimes graft or bud is rejected, even if within species
4) Season and growth state - best when cambium is active, but without leaf growth
5) Environment - must supply proper temperature, humidity, etc.

Front 51

TYPES OF GRAFTING

Back 51

see page 92

Front 52

Types of Budding

Back 52

see page 93

Front 53

pruning

Back 53

removal of plant parts, branches, shoot tips, buds, roots, etc.

Front 54

dehorning

Back 54

heavy drastic pruning of large limbs; should be avoided at all times;
also called pollarding.

Front 55

thinning out

Back 55

removal of branches back to their point of origin.

Used to:
1) decrease density of the canopy
2) encourage other branches to grow and rejuvenate plant
3) redirect growth

Front 56

heading back

Back 56

removal of the terminal portions of a branch.

Used to:
1) increase density of the canopy
2) encourage branching

Front 57

pinching

Back 57

removal of the young, succulent tips of shoots.

Front 58

hedging

Back 58

removal of growth flushes on hedges or shrubs to shape canopy and induce
dense growth.

Front 59

disbudding

Back 59

removal of excessive flower buds on flowering pot plants.

Front 60

root pruning

Back 60

pruning of roots, usually with a shovel, to prepare plants for transplanting

Front 61

OBJECTIVES OF PRUNING

Back 61

1) Health and safety

2) Maintain desired form

3) Dwarfing

4) Invigoration

5) Increase productivity

6) Equalize root/shoot ratio

7) Develop strong branch framework

Front 62

topiary

Back 62

pruning to produce a 3-dimensional design or form.

Front 63

espalier

Back 63

- pruning to produce a 2-dimensional design or form.

Front 64

Wide (Y) Crotch Angle

Back 64

very strong, select for when pruning

Front 65

Narrow (V) Crotch Angle

Back 65

very weak, selectively prune-out

Front 66

CORRECT METHOD TO PRUNE A BRANCH

Back 66

Called Target Pruning

Front 67

FACTORS TO CONSIDER ON WHEN TO PRUNE
Growth State:

Back 67

best when inactive or dormant

Front 68

FACTORS TO CONSIDER ON WHEN TO PRUNE
Susceptibility to winter injury

Back 68

for plants easily damaged by winter freezes

prune after cold of winter
remove all winter killed tissue
you may need to allow some spring growth to tell if tissue is dead or not.

Front 69

FACTORS TO CONSIDER ON WHEN TO PRUNE
Time of flower bud formation on flowering plant

Back 69

a) spring flowering plants:
flower on last years growth (2 year old wood); i.e. flower buds present since last summer or fall.
therefore, prune right after flowering in spring and before new buds form.

b) summer or fall flowering plants:

flower on current years growth (1 year old wood); i.e. flower buds form on new growth of current year.
therefore, prune fall, winter or early spring, but best to prune after cold of winter and before new growth starts in spring.

Front 70

FACTORS TO CONSIDER ON WHEN TO PRUNE
transplanting

Back 70

pruning should be to equalize root/shoot ratio, thus, decrease transplanting shock.
To equalize root/shoot ratio:
a) thin-out immediately after or at the time of transplanting
b) root prune before transplanting (months to years).

Front 71

Chemical Pinching Agents

Back 71

Chemicals that selectively kill or disrupt shoot tips to remove apical dominance.
1) Atrinal
2) Off-Shoot-0
3) Maleic hydrazide
4) Emgard 2007

Front 72

pest

Back 72

any undesirable organism that is injurious to plants, either directly (ex. insects, or fungi)
or indirectly (ex. weeds).

Front 73

THREE PREREQUISITES OF PEST DAMAGE OR INFECTION

Back 73

1) plant susceptible
2) pest present
3) proper environment

Front 74

PEST DAMAGE CONTROL
1) Plant Resistance

Back 74

a) Genetic Resistance - this is the "ideal" method of pest damage control

Front 75

PEST DAMAGE CONTROL
2) Proper Environment

Back 75

a) Favorable for plant
b) Unfavorable for pest

Front 76

PEST DAMAGE CONTROL
3) Eliminate Pest

Back 76

a)Quarantine - usually governmentally imposed
b) Sanitation - wash pots and tools, hoses off ground, propagate clean plants, etc.
c) Physical Control - bug traps, screens, sticky boards, etc.
d) Biological Control - the use of one organism to control another organism.
1) Bacillus thuringiensis - a bacterium that controls caterpillars
2) grass carp (or white amour) - a fish that eats submerged aquatic weeds
3) predaceous mites - eat other mites and small insects
4) parasitic wasps - lay eggs inside other insects
5) Trichoderma - a fungus that controls other fungi
6) allelopathy - secretion of chemicals by one plant that retards the growth of surrounding
plants
e)Pesticides - chemicals used to control pests; ex. fungicide, bactericide, insecticide, miticide,
herbicide.

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Modes of Action - pest control

Back 77

1) Contact Pesticide (insects and weeds)
2) Systemic Pesticide (insects and weeds)
3) Stomach Poison (insects only)

Front 78

Integrated Pest Management (IPM) -

Back 78

the use of all strategies of pest damage control (resistance, cultural, biological, environmental and chemical) to minimize the economic impact of pests.