Plant Propagation Final Exam OSU Study
Simple layering
-Bending an intach shoot to the ground and covering a single portion of stem with soil. -Bending, twisting, cutting, or girdling stimulate root initiation
Chip budding
-a chip of wood of the rootstock is replaced by a scion chip of desired cultivars -greater production window than T-budding -greater graft union than T-bud
Corm
-a unique geophyte structure in which the base of the stem axis is swollen, had nodes and internodes in a dry membranous tunic -Structure: solid stem structure with distinct nodes and internodes
What are the Limitation of Micropropagation?
-expense -species specificity -production scheduling and marketing -pathogen contamination
What are the advantages of 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
T-budding
-limited to rootstocks that range from 1/4-1 inch in diameter -rootstocks must be actively growing so the bark will slip
Side-tongue graft
-limited to small plants -tongue provides interlock and helps support the scion
What are the advantages of Micropropagation?
-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 disadvantages of clones as cultivars?
-monoculture -slow and costly reproduction -potential for genetic variation -potential for systemic pathogens
Trench layering
-mother plants are established in a sloping position -shoots of established plants can be placed horizontally at the base of the trench
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
-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.
Reasons for layering sucess
-physical attachment to the mother plant -increased photosynthates and hormones accumulated in the rooting area -excluding light in the rooting zone -invigoration and rejuvenation -Utilizing seasonal effects on rooting
What is plant morphology in response to the In Vitro environment?
-reduced leaf size and number of cell layers comprising the leaf -reduced wax formation -stomatal malfunction -low photosynthetic ability
Mound layering
-shoots are cut back to the ground -as new shoots emerge, rooting medium is mounded at the base of the new shoots -new roots form at the base of covered shoots
Stage 2 Shoot Multiplication
-to maintain the culture in a stabilized state and multiply microshoots to the number required for rooting -PGR: high ratio of cytokinin
Stage 3 Root Formation
-to root microcuttings and prepare them for transfer to ex vitro conditions -PGR: high auxin ratio
Advantages of Budding
-very efficient use of scion or bud wood -may result in a stronger union -simplicity and speed -useful for amateur horticulturalists -provides flexibility
What is the criteria for successful exploitation of a 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
Recombinant DNA technology
a gene from one organism is inserted into the genome of another individual to produce a new genotype
Serpentine layering
a horizontal shoot or vine is covered at individual nodes for rooting
Runners
a natural form of layering in which a specialized stem grows laterally from the crown of the plant and takes root at alternate nodes to produce a new plant that provides for vegetative expansion of the original plant
Chimera
a plant is composed of a mixture of tissues with different genotypes, also referred to as mosaics
Pseudobulbs
a pseudobulbs(False bulb) is 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
Patch budding
a rectangular patch of bark is removed from the rootstock and replace by a patch of bark from the scion that contains a quiescent bud
Offsets
a specialized leafy plant stem that develops from the base of many monocots and is used for propagation
Rhizomes
a specialized stem structure in which the main axis of the plant grows horizontally at, or just below, the ground surface
Bulb
a specialized underground organ consisting of a short fleshy, stem axis, bearing at its apex a growing point or a flower primordium enclosed by thick, fleshy scales
Stolons
a specialized underground stem that grows laterally from the crown of the plant to produce either another plant or a tuber.
Bud-sport
a sudden change in a single branch due to a mutation apparently arising from a single bud
Tuber
a swollen modified stem with nodes and internodes which functions as an underground storage structure as well as an organ of vegetative propagation
Vitrification
a translucent, water-soaked, succulent appearance that results in cultures that fail to proliferate
Tunicate bulb
a type of bulb scale characterized by concentric layers of fleshy tissue
Scaly bulb
a type of bulb structure in which scales are fleshy, separate, and not enclosed in a membranous layer
Bulbils
a type of bulblet produced in the aerial portion of the plant enclosed within a dry, membranous scale
Twin-scaling
a variation of bulb cutting using a segment of 2 scales with portion of the basal plate
Fleshy roots
adventitious buds and roots are produced from it
Compound layering
an entire branch is laid horizontally to the ground and covered with rooting media
Root graft
an entire root system or pieces of root serve as the rootstock for the graft
Tissue culture
an inclusive term referring to procedures used to maintain and grow plant cells and organs in aseptic culture.
Propagule
any plant part used as the starting point of a propagation process
Crippling
bending or cutting half way through the rootstock stem above the bud union
Offsets
bulblets grown to mature size
Open case
bury the graft of potted plants in moist peat
Cell suspension
callus cells grow in liquid culture that is constantly agitated. Agitation breaks cells apart, preventing them from forming large callus clump
Basal cuttage
cutting into the base of a bulb to stimulate adventitious bulblet formation
Scoring
cutting into the base of the bulb
Girdling
cutting through the bark and cambium completely around the rootstock stem
Mutation breeding
development of new clones with the use of mutagenic agents
Leptomorph
elongated, indeterminate rhizomes
Somatic hybridiation
fusion of protoplasts from two genotypes/species
True-to-Name(TTN)
implies that the plant conforms to the specific characteristics of the specified cultivars
True-to-Type(TTT)
implies the plants conform to the phenotypic expectations of the specific cultivars
Scaling
individual scales are removed from mother bulb, and adventitious bulblets form at the base of each scale
Layering
is a way of rooting cuttings in which adventitious roots are initiated on a stem while still attached to the plant
What is the goal of vegetative propagation?
is to select a single source plant of superior characteristics and to reproduce populations of progeny plants with identical genotypes that are its direct descendents.
Propagation Ratio(PR)
number of new microshoots produced per subculture
Side-veneer graft
often graft is covered with moist peat by burying the potted plant until scion has healed.
Mutation
permanent genetic change involving some part of the DNA molecule
Protoplast culture
plant cells without a cell wall, removed by microbial enzymes
Ovule culture and Ovary culture
pollen is added to the ovary while it is forming in tissue culture, resulting fertilized embryos
Aseptic Seed Culture
primarily used for orchid seed germination because the seed is so small and contains no seed storage reserves
Back bulbs
pseudobulbs that do not have foliage
Green bulbs
pseudobulbs that have foliage
Scooping
removal of basal plate
Callus
results from cell division of non-differentiated parenchyma cells
Crowns
root-stem juncture of the plant
Seedling selection
selecting a single plant that is genetically unique from a seedling population to be the start of a new clone cultivar
Pachymorph
short, thick, fleshy determinate rhizome
Inverted t-budding
similar to t-budding but the cut is inverted to allow for better drainage
Synthetic seed production
somatic embryos enclosed in an artificial seed coat, which may be a way of sowing somatic embryos for mass propagation
Tuberous roots
swollen root system attached to the crown
Tuberous stem
swollen stem produced by enlargement of the hypocotyl
Drop layering
the bases of shoots in plants established in containers and covered
Somatic Embryogenesis
the development of embryos from vegetative cells rather than from union of male and female gametes
Anticlinal
the direction of cell division in an end-to-end position to produce a continuous layer
Periclinal
the direction of cell division in an side-to-side position to increase numbers of cell layers
Hot-pipe callusing system
the graft union is kept warm by recirculating hot water in a PVC pipe
Organogenesis
the process of developing adventitious organs, such as leaves, shoots, or roots, form cells or tissues
Subculturing
the process of dividing stems or tissue from a tissue culture into smaller pieces and then transferring them to a fresh medium to multiply the tissue culture
Clonal selection
the process of selecting an individual plant or plant part to create a clone
Cloning
the process of vegetatively propagating a clone
Bark graft
the scion is inserted between the bark and wood of the rootstock
Tubercle
the small aerial tubers produced in leaf axils of certain species
Embryo culture and Embryo rescue
tissue culture of immature embryos that require controlled conditions to complete development
Stage 1 Establishment
to successfully place an explant into aseptic culture and an in vitro environment that promotes stable shoot production
Approach graft
two independent, self-sustaining plants are grafted together
Light
typical irradiance level between 40 and 80 umol
Bulblet
underground miniature bulb
Side-stub graft
used for branches that are too big for whip and tongue, but not large enough for cleft graft
Somaclonal variation
variation induced in plants produced from populations of cells in culture
Closed case
waxing may be omitted if bare-root grafts are protected in boxes containing moist peat
Air layering
wrapping an girdled aerial stem with rooting medium and causing adventitious roots to form
What are mutation agents?
x-rays, gamma rays, neutrons, chemicals
Air exchange
Co2, O2 C2H4 impact shoot development in culture
Protoplasts can absorb ________, proteins, and other large macromolecules
DNA
What are the 5 factors that affect the control of the tissue culture environment?
Temp, light intensity, photoperiod, light quality, air exchange
Bulb cutting
a bulb is cut into fragments of 3 or 4 bulb scales attached at the basal plate
Indirect Organogenesis
a developmental sequence involving an intervening callus stage