Exam 2 Part 2 Grafting Flashcards Preview

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Flashcards in Exam 2 Part 2 Grafting Deck (26)
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1

Grafting

the art and science of connecting two or more pieces of living plant tissue together in such a manner that they will unite and subsequently grow and develop as one plant.

2

scion

the short piece of detached shoot containing several dormant buds, which, when united with the stock, comprises the upper portion of the graft and from which will grow the stem and branches of the grafted plant.

3

stock

the lower portion of the graft which develops into the root system of the grafted plant. It may be a seedling, a rooted cutting, a layered plant, or a mature tree

4

budding

a type of grafting, except that the scion is reduced in size to consist of a vegetative bud

5

interstock

a piece of stem inserted by means of two graft unions between the scion and the rootstock.

6

graft union

the juncture at which the scion and stock of a grafted plant have successfully united.

7

double working

double graft involving a rootstock, interstock, and scion whether done in one or two steps

8

incompatibility

the inability of a grafted scion and stock to produce a successful graft union or to have the resulting grafted plant develop unsatisfactorily

9

vascular cambium

a thin tissue of the plant located between the bark (phloem) and the wood (xylem)

10

callus

mass of parenchyma cells that develop from and around wounded plant tissue. It occurs at the junction of a graft union arising from the living cells of both scion and stock

11

reasons for grafting

LPerpetuate clones that can’t be conveniently propagated by other asexual methods –many fruit and nut species –some woody ornamentals –cutting propagation impractical for many plants

12

reasons for grafting

LObtain benefits of certain rootstocks – Stress tolerance – Pest resistance – Size control LApple (East Malling Research Station) L‘Malling 27’: 4-6 ft tall L‘MM111’: Semi-dwarf, disease resistant, and propagates well

13

2 types of rootstocks

seedling

clonal

14

advantages of seedling rootstocks

LSimple and economical to produce LViruses usually not seed transmitted LSometimes, better developed root system as compared to cuttings or clonal rootstocks

15

disadvantages of seedling rootstocks

LGenetic variation among seedlings LReduce this variability by: –careful selection of seed source –protection from cross pollination –grading nursery trees at digging –discarding off types before grafting

16

clonal rootstocks

LPropagated by mound layering or rooted cuttings

17

advantages of clonal rootstocks

LUniformity LPreserves special characteristics and specific influences –growth (dwarfing, invigorating) –flowering (precocity) –disease resistance –soil adaptation

18

disadvantages of clonal rootstocks

LPotential for transmission of systemic pathogens to ‘clean’ scions LExpense

19

whip or splice graft

LGenerally done in late winter when both stock and scion are dormant

20

whip and tongue

LGenerally done in late winter when both stock and scion are dormant

21

topworking

Changing the scion cultivar by grafting onto established plantings or rootstocks

22

graft incompatibility

Inability of parts of 2 or more different plants to form a successful graft union or grow satisfactorily after grafting

23

localized incompatibility

LUsually overcome by insertion of a mutually compatible rootstock LMust be physical contact between the two grafting partners

24

translocated incompatibility

LNot usually overcome by insertion of mutually compatible interstem LA biochemical signal that is translocated across the graft union causes the failure LVirus induced failure can be included here

25

causes and machanisms of incompatibility

1.Physiological and Biochemical –Chemicals that inhibit normal graft healing 2.Modification of Cells and Tissues –Tissues fail to properly develop through the callus bridge 3.Cell Recognition of the Grafting Partners –Some type of communication between the cells of the two partners (Pollen/Stigma)

26

correcting incompatibility

LOnly localized incompatibility can be corrected –Interstock –Inarching