Plant Propagation Final Exam

T or F: The rootstock is used in grafting and budding can be propagated from seeds or other vegetative propagation methods.

True

T or F: Auxins are regularly used in grafting and budding to promote better results.

False

T or F: Budding is a form of grafting, where a scion of reduced size is used.

True

T or F: Scion provides the root system in a grafted plant

False

It's the easiest to form graft unions from which of the following combinations?

a. Between genera within a family

b. Between species within a genus

c. Within the same clone

c. Within the same clone

Which type of plant is not generally grafted or budded?

a. Monocots

b. Dicots

c. Gymnosperms

a. Monocots

Which on of the practice is NOT appropriate in grafting and budding?

a. Properly seal all cut surfaces

b. Union of cambium layers exact

c. Maintain a temperature of 110 °F for graft union formation

d. A high humidity is needed for graft union formation.

c. Maintain a temperature of 110 °F for graft union formation

Quiz 17

Strawberry plants produce horizontal stems that roots on alternate nodes to produce a new plant. This new plant is a ?

a. Runner

a. Runner

A branch is bent to the ground and a single point is covered with soil. This type of layering is?

a. Simple layering

b. Serpentine layering

c. Air layering

d. Compound layering

A. Simple layering

Plants are planted with a slope in the field and later pulled down to the ground into a shallow trench to induce etiolation at the base of the new-emerging shoots. This layering is?

a. Mound layering

b. Drop layering

c. Air layering

d. Trench layering

d. Trench layering

What type of specialized stem does ONION have?

a. Scaly bulb

b. Tuber

c. Corm

d. Tunicate bulb

a. Scaly bulb

What type of specialized stem does POTATO have?

a. Rhizome

b. Tuber

c. Corm

d. Pseudobulb

b. Tuber

Which one of the following plants produce corms?

a. Orchid

b. Ginger

c. Gladiolus

d. Potato

c. Gladiolus

Which type of rhizome has elongated and indeterminate growth?

a. Leptomorph

b. Pachymorph

a. Leptomorph

Which one of the following ways is NOT an acceptable method to propagate periclinal chimeras?

a. Crown division

b. Stem cutting

c. Root cutting

d. Layering

c. Root cutting

Which one of them is a stable chimera over time and has its horticultural advantage?

a. Sectorial

b. Mericlinal

c. Periclinal

c. Periclinal

Which one of the following is NOT an advantage of using clones as cultivars?

a. Allows the control of phases in plant development

b. Ability to combine more than one genotypes into a single plant

c. Uniformity of populations

d. Potential for systemic pathogens.

d. Potential for systemic pathogens.

What is grafting?

the union of a root system (understock/rootstock) with a shoot system (scion) in such a manner that the subsequently grow and develop as on composite plant.

What is budding?

is a form of grafting. The scion is reduced in size and usually contains only one bud.

What are the reasons for Grafting or Budding?

1. perpetuating clones desired for their fruiting, flowering or growth characteristics

2. combine different cultivars into a composite plant.

3. changing cultivars of established plants

4. Repair graft for injuries

5. Disease indexing test for virus diseases

6. Study of plant developmental and physiological processes.

What are the benefits of Interstocks?

1. reduce vegetative growth and enhance reproductive growth

2. obtain special form of plant growth.

3. commonly referred to as a double working

4. this makes it possible to avoid certain kind of incompatibility

5. it may posses a particular characteristic not possessed by either the rootstock or the scion.

What are the benefits of Scions?

1. plant growth rates

2. fruit characteristics

3. yield

4. plant form

what are the benefits of rootstocks?

1. Greater resistance to environmental stress and disease

2. controlling size of grafted plants

3. Hastening reproductive maturity

4. Hastening plant growth rate and reducing nursery production time

5. improving transplanting success

Stage 1 of the formation of the graft union

Lining up vascular cambium of the rootstock and scion

Stage 2 of the formation of the graft union

wounding response

Stage 3 of the formation of the graft union

Callus bridge formation

Stage 4 of the formation of graft union

would repair xylem and phloem- differentiation of vascular cambium across the callus bridge

Stage 5 of the formation of graft union

Production of secondary xylem and phloem from the new vascular cambium in the callus bridge

what are the basic two types of repair graft?

Inarching and Bridge graft

Inarching

seedlings planted beside the damaged tree, or suckers arising at is base, are grafted into the trunk of the tree provide a new root system

-used to replace or repair damaged roots

bridge graft

scion wood is used to reestablish a connection for water, nutrient and carbohydrate supply.

-used to repair damaged trunks or stems

What are the factors that influence graft union success?

1. incompatibility

2. plant species and type of graft

3. environmental conditions during the following grafting

4. growth activity of the rootstock

5. polarity

6. the craftsmanship of grafting

7. virus contaminations, insects and diseases

8. plant growth regulators and graft union formation

9. post grange- bud forcing methods

What are the external symptoms of graft incompatibility?

- failure to form a successful graft or bud union

-yellowing foliage, early defoilation

-premature death of trees

-differences in growth rates or vigor between the stock and scion

-differences in growth cycles

-overgrowth, above or below the graft union

-suckering of the rootstock

-graft component break apart cleanly at the graft union

Are any PGR used in the commercial operations of grafting or budding?

No

How to control the temperature and humidity environments in grafting?

-lower temperatures slow callus formation

-too high temperatures will deplete carbohydrate reserves.

-outdoor grafting should take place at a time of year when favorable temperatures are expected and the vascular cambium is in an active state.

-air moisture levels below the saturation point. inhibit callus formation; desiccation of cells increase as the humidity drops

-water is one of the driving forces for cell enlargement and necessary for callus bridge formation.

What does "slipping bark" mean?

-vascular cambium is actively dividing

-neccessary for T-budding and bark grafting

What is "bleeding" rootstock?

strong root pressure, excessive sap flow

Is polarity always maintained in grafting? What are the exceptions?

-it needs to be maintained during grafting

99% of all graft failure is due to what? What are other reasons?

- mis matched cambium

most of the rest of the failures are the result of incompatibility. some delayed incompatibilities are caused by viruses and phytoplasma.

What are the key points in a successful graft?

- the rootstock and the scion must be compatible

- union of cambium layers exact

- scion should be dormant 1 yr old wood

-proper timing

Grafting is generally done on dicots or monocots?

Grafting is generally limited to dicots and gymnosperms

- grafting of monocots is more difficult and has lower percentage of "takes"

Will grafting be successful between species within a genus?

Sometimes

Will grafting be successful between genera within a family?

remote

Which type of graft is most commonly used for the grafting of cactus?

What type of graft is used a lot in bench grafting cucurbit plants?

Hole Insertion Graft

What is graft type that is one of the oldest graft method, allows 2 scions, and is used in top working established trees?

Cleft Graft (Split)

What is the graft type requires equal diameters of rootstock and scion, and It heals quickly due to considerable cambium contact?

Whip and Tongue

11-13 C

What is layering?

a way of rooting cuttings in which adventitious roots are initiated on a stem while still attached to the plant

What are the reasons that make layering work successfully as a propagation method?

-physical attachment to the mother plants

-increased photosynthesis and hormones accumulated in the rooting area

- excluding light to in the rooting zone

- inrigonation and rejuvenation

-utilizing seasonal effects on rooting

bulb

a specialized underground organ consisting of a short fleshy, stem sizes, bearing at its apex

bulbils

a type of bulblet produced in the aerial portion of the plant enclosed within a dry, membranous scale

Corm

a unique neophyte structure in which the base of the stem axis is swollen, had nodes and internodes in a dry membranous tunic

Tuber

a swollen modified stem with nodes and internodes which functions as an underground storage structure as well as an organ of vegetative propagation

Fleshy roots

adventitious buds and roots are produced from it

Tuberous roots

swollen root system attached to the crown

Tuberous stem

swollen stem produced by enlargement of the hypocotyl

Rhizome

a specialized stem structure in which the main axis of the plant grows horizontally at, or just below, the ground surface

Pseudobulbs

a specialized storage structure, produced by many orchid species, consisting of an enlarged, fleshy section of the stem made up of one to several nodes.

What are the basic 3 parts in a bulb?

basal plates, scales, contractile roots/droppers

What are the two types of bulbs?

Tunicate (onion, daffodil, and tulip) and Scaly (lily)

What are the different propagation methods got plants that produce bulbs?

-offsets

-bulblet formation on stems- stem cuttings

- bulblet formation on scales (scaling)

-basal cuttage

-leaf cuttings

-bulb cuttings

Corms propagation

-new corms

- corm division

- cormels

Tuber propagation

-division

- adventitious roots

- stem and leaf cuttings

Rhizome propagation

- division of clumps and rhizomes

- culm cuttings

Pseudobulbs propagation

- offshoots

- division

- back bulb or green bulbs

What are the two types of rhizomes?

Pachymorph and Leptomorph

Pachymorph

short, thick, fleshy determinate rhizome (Iris, Ginger)

Leptomorph

Elongated indeterminate rhizomes (Spreading Bamboo)

Advantages of using clones as cultivars

- genetic improvement and selection

-uniformity of populations

-control of phases of plant development

- combine more than one genotype into a single plant (grafting)

Disadvantages of using clones as cultivars

-monoculture

- slow and costly reproduction

- potential for genetic variation

- potential for systemic pathogens

Criteria for successful exploitation of a bud sport?

1. Mutation must be dominant

2. cells that has mutated must occupy a significant part of the meristem

3. mutation (trait) must be conspicuous so that the new selection can be identified by that mutation

What is clonal selection?

the process of selecting an individual plant or plant part to create a clone

What is a bud sport?

a sudden change in a single branch due to a mutation apparently arising from a single bud

What is a chimera?

( a mix) a plant is composed of a mixture of tissues with different genotypes, also referred to as mosaics

Anticlinal division

the direction of cell division in an end to end position to produce a continuous layer

Periclinal division

the direction of cell division in an side to side position to increase numbers of cell layers

Periclinal Chimera

-mutation occupies on the outer layer of cells surrounding the meristem, inner core of cells are un-mutated

-very stable

Mericlinal chimera

-mutation occupies only part of the outer cell layer, resulting in longitudinal streaks of mutated and nonmutated cells

-generally unstable they tend to convert to periclinal, or revert to the nonmutated form.

Sectorial Chimera

-mutated cells occupy a discrete sector of the stem, including a sector of the meristem

-generally very unstable, convert to mericlinal or periclinal or revert to wild-type or all mutant

Periclinal Chimera Propagation

- must be reproduced Bia whole shoot apex cuttings, and can not be propagated by root cuttings or anything else that produced adventitious buds.

How are Graft Chimera formed?

The graft union produces callus to bridge the graft wound. Some buds are de novo. If they arise from tissues that are part rootstock and part scion the resulting bud is chimeric.

What causes phenotypic variations within clones?

- environment by genotype interactions

- ontogenetic aging

- permanent genetic variation

- infection by systemic pathogens

- viruses etc.

True to name

requires that plants being produced and sold be correctly labeled by scientific name, cultivar name or borth

True to Type

implies the plants conform to the phenotypic expectations of the specific cultivar

How to eliminate pathogens in clonal propagation?

- selection of uninfected pathogens

- shoot apex culture

- micrografting

- heat treatments

- thermotherapy

- growing seedlings

What are the sources to collect clonal propagules?

-commercial plantings as nursery sources

-production materials within the nursery

-stock blocks

-clonal selection and pedigreed production programs

-repositories botanical gardens, and plant collections

-Quarantine and movement of vegetatively propagated material

What are the advantages of plant tissue culture?

- mass propagation of specific clones.

-production of pathogen free plants

- clonal propagation of parental stock for hybrid seed production

- Year round nursery production

-Germplasm preservation

What are the applications of plant tissue culture?

-Where propagation rate is relatively slow and plants are typically divided (Hosta)

- genetic engineering

- cultivars with high market value (orchids)

- propagation of difficult to root plants

-conservation of endangered species

What are the limitations of plant tissue culture?

-Expense (trained labor, equipment, specialized techniques)

-Species specificity

- Production scheduling and marketing

- Pathogen contamination

-variability and off type individuals

-acclimization

What is the fundamental ability of plant cells that is the base of tissue culture?

What are the two regeneration methods to produce platelets?

Axillary shoot formation and Adventitious shoot formation

What are the two regeneration methods explant sources?

Indirect and Direct

Which generation has the highest PR?

Shoot Multiplication

T or F: The higher the PR the better

True

Stage I Establishment

to successfully place an explant into aseptic culture and an in vitro environment that promotes stable shoot production

- explant source selection

-explant disinfection

- culture medium (Murashige and Skoog)

- stabilization, when explants produce a consistent number of "normal" shoots after subculturing

Stage II Shoot Multiplication

to maintain the culture in a stabilized state and multiply micro shoots to the number required for rooting

- PGR: high ratio of cytokinin

- Propagation ratio: Number of new micro shoots produced per subculture

- PR is greater from adventitious shoots than from ancillary shoot cultures, but greater proportion of off-type shoots with adventitious origin.

Stage III Root Formation

to root micro cuttings and prepare them for transfer to ex vitro conditions

- PGR: high auxin ration

- in vitro rooting

- ex vitro rooting

Stage IV - Acclimatization

to shift from a heterotrophic to an autotrophic reaction

-Acclimatization

- from in vitro to ex vitro

- lower humidity

- greater light intensity

- non sterile environment

-first two weeks are critical

- grow under indirect light and higher humidity

- slowly lower humidity over 2nd week

- greatest loses during this stage because of bad acclimatization