Plant Propagation Exam Two

(a) the goal is to reproduce plants with identical genotypes from a source plant with desirable characteristics (phenotype)

(b) the process of selecting an individual plant or plant part to create a clone (following asexual propagation)

choices: clonal selection or asexual propagation

asexual propagation: the goal is to reproduce plants with identical genotypes from a source plant with desirable characteristics (phenotype)

clonal selection: the process of selecting an individual plant or plant part to create a clone (following asexual propagation)

name some advantages of asexual propagation:

• true-to-type

• uniformity aka throughout the year propagation

• control phases of plant development

• combine multiple genotypes in a single plant (grafting)

• longer window to propagate

• facilitate propagation, aka only means to propagate due to cost and dormancy

name some disadvantages of asexual propagation

• monoculture

• slow reproduction rate

• lack of genetic variation for breeding and selection

• potential for propagating systematic pathogens from clonal sources

• not much diversity for resistance against pests and pathogens

• potential for latent genetic mutation

• labor-intensive and costly

(a) new roots and buds formed from the cells and tissues of previously developed shoots and roots, clonal propagation leads to this

(b) shoots which arise from ANY location on the plant except stem tips or leaf axils (any new shoot on propagule)

(c) roots which arise from an organ/portion of the plant other than the original root system (any new root on propagule)

choices: adventitious shoots, adventitious roots, adventitious organs

adventitious organs: new roots and buds formed from the cells and tissues of previously developed shoots and roots, clonal propagation leads to this

adventitious shoots: shoots which arise from ANY location on the plant except stem tips or leaf axils (any new shoot on propagule)

adventitious roots: roots which arise from an organ/portion of the plant other than the original root system (any new root on popagule

(a) the capability of previously differentiated cells to initiate cell division and form a new meristematic growing point (not all cells/plants can do this)

(b) an irregular mass of parenchyma cells, base of cutting, comes from vascular cambium, roots can emerge though not essential for rooting

(c) the condition inherent in a root or shoot cutting that exhibit different properties in opposite parts, distil and proximal ends, (regulated by auxin)

choices: polarity, dedifferentiation, callus

dedifferention: the capability of previously differentiated cells to initiate cell division and form a new meristematic growing point (not all cells/plants can do this)

callus: an irregular mass of parenchyma cells, base of cutting, comes from vascular cambium, roots can emerge though not essential for rooting

polarity: the condition inherent in a root or shoot cutting that exhibit different properties in opposite parts, distil and proximal ends

(a) the ability of root cuttings to develop naturally on aerial portions that are attached to the mother plant, may or may not be visible, have organized root meristem but are dormant until stimulus is provided (not roots just buds)

(b) also known as wound-induced roots, this is when the outer injured cells die to create adventitious roots

choices: de novo adventitious roots or preformed root initials and primordia

preformed root initials and primordia: the ability of root cuttings to develop naturally on aerial portions that are attached to the mother plant, may or may not be visible, have organized root meristem but are dormant until stimulus is provided (not roots just buds)

de novo adventitious roots: also known as wound-induced roots, this is when the outer injured cells die to create adventitious roots

name the steps of de novo adventitious root formation

• outer injured cells die and a necrotic plate is formed, the would is sealed with a corky material and the xylem may plug with gum, it protects the plant from desiccation and pathogens

• living cells behind the plate will start to divide and a callus will form which develop into a wound periderm

• certain cells of the vascular cambium and phloem begin to divide and de novo adventitious roots are formed

1. dedifferentiation of specific cells in specific species

2. formation of root initials, cells near vascular tissue are now meristematic

3. organization into root primordia, differentiation into specific root tissues

4. development of emergence of root primordia, the formation of vascular connections

(a) these cuttings must generate adventitious roots, buds, and shoots, they have preformed primary meristems and wound induced secondary meristems

(b) these cuttings must generate adventitious shoots and may produce adventitious roots, generally a shoot comes first then new roots

(c) an endogenous substance that stimulates rooting, it can be auxin or a combination of substances with auxin which promote rooting

choices: root cuttings, shoot cuttings, or root morphogen

shoot: these cuttings must generate adventitious roots, buds, and shoots, they have preformed primary meristems and wound induced secondary meristems

root: these cuttings must generate adventitious shoots and may produce adventitious roots, generally a shoot comes first then new roots

root morphogen: an endogenous substance that stimulates rooting, it can be auxin or a combination of substances with auxin which promote rooting

the juvenile to mature gradient in seedling trees, the physiologically mature section of the tree is at the shoot tips while the most juvenile section is at the root-shoot junction

there is an inverse relationship between physiological age and chronological age

the cone of juvenility

name key differences between juvenile and mature plant growth:

• juvenile material only have vegetative growth, no flowering

• mature material may undergo morphological changes

• juvenile material is easy to root

• mature material is difficult to root

name the plant hormones (include synthetic ones if applicable):

• Auxin - triggers root initiation not elongation

  • the most promotive, applied exogenously via rooting compounds

    • IAA>IBA>NAA>2,4-D (herbicide)

• Cytokinin - promote bud and shoot formation, inhibit roots

  • inhibits rooting, may promote with auxin, cytokinin ratio is high

    • 6-benzylaminopurine (BAP BA)

    • Kinetin

• Gibberellins - high concentrations inhibit root initiation, low concentrations promote root initiation, stimulate shoot development

  • GA3

• Ethylene - root initiation, inhibit elongation, promotes falling of leaves (abscission)

  • promote rooting in herbaceous, little effect on woody cuttings, involved in wounding process

• Abscisic acid - inhibits root formation and bud formation and shoot formation, can promote rooting with auxin

  • generally inhibitive, can promote in some species with auxin

(a) auxin is required for root formation

(b) auxin is not required for roots

choices: active or inactive auxin

active auxin: auxin is required for root formation

inactive auxin: auxin is not required for roots

(a) herbaceous plants/succulents, rapid root formation, plants have essential root morphogens + auxin, auxin can enhance rooting but is not required

(b) most woody plants, natural root morphogens are present but auxin is limited, auxin application will enhance rooting

(c) select woody species and recalcitrant species, plants lack morphogens/sensitivity to morphogens, auxin will not help rooting

choices: difficult to root, east to root, moderately easy to root

easy to root: herbaceous plants/succulents, rapid root formation, plants have essential root morphogens + auxin, auxin can enhance rooting but is not required

moderately easy to root: most woody plants, natural root morphogens are present but auxin is limited, auxin application will enhance rooting

difficult to root: select woody species and recalcitrant species, plants lack morphogens/sensitivity to morphogens, auxin will not help rooting

(a) the growth of plant cells/tissues/organs in a sterile environment on a nutrients culture medium, a technique

(b) this is a type of tissue culture used to propagate plants, this is sued for the production of large quantities of identical plants on a nutrient culture and sterile/controlled environment

(c) a single plant cells has the potential to regenerate into an entire plant

choices: totipotency or micropropagation or tissue culture

tissue culture the growth of plant cells/tissues/organs in a sterile environment on a nutrients culture medium, a technique

micropropagation this is a type of tissue culture used to propagate plants, this is sued for the production of large quantities of identical plants on a nutrient culture and sterile/controlled environment

totipotency a single plant cells has the potential to regenerate into an entire plant

what do the three different cytokinin:auxin ratios do?

• high cytokinin to auxin

  • promote shoot formation

• low cytokinin to auxin

  • promote root formation

• equal cytokinin to auxin

  • both shoot and root formation

name the stages of micropropagation:

• Stage 0: donor plant selection

  • stock plants are manipulated prior to collection of explants

• Stage I: establishment

  • placing tissue into culture media and initiate microshoots with an equal ratio of cytokinin to auxin

• Stage II: shoot multiplication

  • inducing multiple shoots, high cytokinin to low auxin levels

• Stage III: root formation

  • initiating roots, low cytokinin to high auxin levels

• Stage IV: acclimatization

  • gradually moving plants to open air conditions and media

(a) means the production in a test tube or other similar vessel where culture conditions and medium (agar) are controlled for optimum growth during tissue culture

(b) rooting of microcuttings occur uring greenhouse growing medium rather than rooting on agar in a test tube, they are treated with auxin and put into plug trays

(c) a piece of the plant used to be initially placed in tissue culture such as a nodal stem piece or portion of plant organs

choices: ex vitro or in vitro or explant

in vitro: means the production in a test tube or other similar vessel where culture conditions and medium (agar) are controlled for optimum growth during tissue culture

ex vitro: rooting of microcuttings occur uring greenhouse growing medium rather than rooting on agar in a test tube, they are treated with auxin and put into plug trays

explant: a piece of the plant used to be initially placed in tissue culture such as a nodal stem piece or portion of plant organs

(a) usually a semisolid support (agar), medium or inorganic nutrient elements (micro and macro nutrients), energy source (sucrose), hormones and vitamins

(b) name the two most commonly used culture media

(c) explant initially grows by elongation of the main terminal shoot

choices: apical dominance, MS or WPM, culture medium

culture medium: usually a semisolid support (agar), medium or inorganic nutrient elements (micro and macro nutrients), energy source (sucrose), hormones and vitamins

MS (murashige & skoog) and WPM (woody plant medium): name the two most commonly used culture media

apical dominance explant initially grows by elongation of the main terminal shoot

name some advantages of micropropagation:

• mass propagation of specific clones

• production of pathogen-free plants

• clonal propagation of parental stock (inbred lines) for hybrid seed production

• year-round nursery production

• germplasm preservation

name some disadvantages of micropropagation:

• special and expensive facilities, trainer personnel, special techniques

• high-volume storage to stockpile products

• pathogen contamination or insect infestation can cause high losses

• variability of off-type individuals can be a risk

(a) the formation of shoots from the explant where buds exit, its meristematic tissue

(b) the use of explant source that does not contain an axillary bud (like roots, stem internodes, leaves, bulb scales), non-meristematic tissue, diploid plants regenerate

choices: axillary shoot formation and adventitious shoot formation

axillary shoot formation the formation of shoots from the explant where buds exit, its meristematic tissue

adventitious shoot formation the use of explant source that does not contain an axillary bud (like roots, stem internodes, leaves, bulb scales), non-meristematic tissue, diploid plants regenerate

the following are coming from axillary shoot formation:

(a) explant comes from shoot tip less than 1mm in size, used as internally developed as a micropropagation system but now mostly used for virus elimination

(b) explant comes from stem with one to four nodes, used for shoot cultures that are most often used in micropropagation systems

(c) explant may include leaves and shoot tip, use is cultures are multiplied by cutting the clump into sections and subculturing each in separate containers

(d) explant source is long shoots which are cut into single nodes and planted vertically, used as axillary buds at each node elongate and grow in length, pattern is repeated by cutting into nodal segments at each subculture

choices: nodal culture,axillary branching, shoot culture, and meristem culture

meristem culture: explant comes from shoot tip less than 1mm in size, used as internally developed as a micropropagation system but now mostly used for virus elimination

shoot culture: explant comes from stem with one to four nodes, used for shoot cultures that are most often used in micropropagation systems

axillary branching explant may include leaves and shoot tip, use is cultures are multiplied by cutting the clump into sections and subculturing each in separate containers

nodal culture explant source is long shoots which are cut into single nodes and planted vertically, used as axillary buds at each node elongate and grow in length, pattern is repeated by cutting into nodal segments at each subculture

the following are coming from axillary shoot formation:

(e) explant is a shoot of several nods planted horizontally the lateral growing points form a thicket of small vertical growing shoots, the layers are subdivided at each subculture and transferred to a new culture when the medium is exhausted

(f) explants are growing points of orchids in culture, secondary protocorms or protocorm-like bodies for rapid regeneration

(g) explant is potato plants to form miniature tubers, the storage organs can be removed and used in the production of virus-free planting stock

(h) small scion shoot tips grafted into a seedling understock, used for virus elimination, propagation method, grafting problems, and rejuvenation

choices: protocorms, stool shoots, micrografting and minitubers

stool shoots explant is a shoot of several nods planted horizontally the lateral growing points form a thicket of small vertical growing shoots, the layers are subdivided at each subculture and transferred to a new culture when the medium is exhausted

protocorms explants are growing points of orchids in culture, secondary protocorms or protocorm-like bodies for rapid regeneration

minitubers explant is potato plants to form miniature tubers, the storage organs can be removed and used in the production of virus-free planting stock

micrografting small scion shoot tips grafted into a seedling understock, used for virus elimination, propagation method, grafting problems, and rejuvenation

all the following come from adventitious shoot formation:

(a) explant comes from leaf pieces/petioles/bulb scales/stem internodes/ roots/callus, often used for micropropagation in monocots, adventitious shoot regeneration is a key step in obtaining plants which have been genetically transformed

(b) explant comes from anther or endosperm culture, used in breeding to obtain haploid or triploids, shoots or somatic embryos may be obtained

choices: regeneration of plants with different ploidy levels or diploid plant regeneration

diploid plant regeneration explant comes from leaf pieces/petioles/bulb scales/stem internodes/ roots/callus, often used for micropropagation in monocots, adventitious shoot regeneration is a key step in obtaining plants which have been genetically transformed

regeneration of plants with different ploidy levels explant comes from anther or endosperm culture, used in breeding to obtain haploid or triploids, shoots or somatic embryos may be obtained

(a) in vitro culture can be effective when a germinating and reproducing procedures when protection from contaminating organisms is needed and specific barriers need to be overcome

(b) can be used for developing roots, shoots, or complete plantlets

(c) can be developed by growing homogenized tissues in liquid cultures

choices: callus cultures, cell suspension culture, reproduction of seedling plants

reproduction of seedling plants in vitro culture can be effective when a germinating and reproducing procedures when protection from contaminating organisms is needed and specific barriers need to be overcome

callus cultures can be used for developing roots, shoots, or complete plantlets

cell suspension culture can be developed by growing homogenized tissues in liquid cultures

the following are from seedling production:

(a) explant is seeds, primarily used to produce orchids, the seeds lack the typical storage reserves found in other seeds and respond well to tissue culture

(b) explant is embryos which are isolated from the fruit and seed coverings, the mature embryos germinate easily in tissue culture to form seedling, used for research, understocks for micrografting, occasionally for propagation

choices: embryo culture or seed culture

seed culture explant is seeds, primarily used to produce orchids, the seeds lack the typical storage reserves found in other seeds and respond well to tissue culture

embryo culture explant is embryos which are isolated from the fruit and seed coverings, the mature embryos germinate easily in tissue culture to form seedling, used for research, understocks for micrografting, occasionally for propagation

the following are from seedling production:

(c) explant is the isolation if immature embryos, primarily used for breeding interspecific crosses, fail to set seed, early embryo development can occur, embryos complete their development in tissue culture

(d) explant is immature ovules or ovaries cultured, unfertilized ovules are excised, grown in culture, supplies with pollen, and fertilized in vitro, used for plant breeding, has the ability to generate haploid plants

choices: ovule and ovary culture or embryo rescue

embryo rescue explant is the isolation if immature embryos, primarily used for breeding interspecific crosses, fail to set seed, early embryo development can occur, embryos complete their development in tissue culture

ovule and ovary culture explant is immature ovules or ovaries cultured, unfertilized ovules are excised, grown in culture, supplies with pollen, and fertilized in vitro, used for plant breeding, has the ability to generate haploid plants

(a) cells without a cell wall

(b) embryos generated from somatic cells (non-sex cells)

(c) somatic embryos enclosed in an artifical seed coat having the potential to regenerate into plants

(d) translucent, water-soaked, succulent appearance

choices: hyperdricity, somatic embryos, synthetic cells, protoplast

protoplast cells without a cell wall

somatic embryos embryos generated from somatic cells (non-sex cells)

synthetic cells somatic embryos enclosed in an artifical seed coat having the potential to regenerate into plants

hyperdricity translucent, water-soaked, succulent appearance

all of these come from calluses:

(a) comes from vegetative tissue, used for research, breeding, and genetic transformation studies, they can be used to produce enzymes, medicine, natural flavors, and colors

(b) comes from callus subcultured from stationary cultures, they are shaken constantly to perptuate callus formation, uses are the same as stationary callus cultures

(c) explant source is protoplasts and the cell wall is digested by fungal enzymes, used in plant research to study basic cell function, breeding, two can form a single cell

choices: protoplast cultures, callus cultures (stationary), callus suspension cultures

callus cultures (stationary) comes from vegetative tissue, used for research, breeding, and genetic transformation studies, they can be used to produce enzymes, medicine, natural flavors, and colors

callus suspension cultures comes from callus subcultured from stationary cultures, they are shaken constantly to perptuate callus formation, uses are the same as stationary callus cultures

protoplast cultures explant source is protoplasts and the cell wall is digested by fungal enzymes, used in plant research to study basic cell function, breeding, two can form a single cell

(a) a genetic variation observed in tissue culture

(b) the development of embryos from vegetative cells

(c) natural plant products (pharmaceuticals) can be produced in cell

(d) a tissue culture procedure used to save embryos from sexual crosses which fail to form fully developed seeds

(e) tip die-back or shoot-tip necrosis is usually caused by this mineral deficiency

choices: somalclonal, cell suspension cultures, embryo rescue, calcium, somatic embryogenesis

somaclonal a genetic variation observed in tissue culture

somatic embryogenesis the development of embryos from vegetative cells

cell suspension cultures natural plant products (pharmaceuticals) can be produced in cell

embryo rescue a tissue culture procedure used to save embryos from sexual crosses which fail to form fully developed seeds

calcium tip die-back or shoot-tip necrosis is usually caused by this mineral deficiency

(a) actively growing shoot tips develop tip die-back, caused by calcium

(b) external surface is sterile, internal might not be pathogen free, pathogen indexing is important

(c) the production of exudates by the explant itself is a problem encountered during tissue culture, antioxidant treatment (ascorbic acid) is most effective

(d) the formation of gall-like growths on the step of micropropagated plants

(e) he autrophic growth in cultures which had previously required auxin/cytokinin for growth

choices: tissue proliferation, shoot-tip necrosis, excessive exudates, internal pathogens, habituation

shoot-tip necrosis actively growing shoot tips develop tip die-back, caused by calcium

internal pathogen external surface is sterile, internal might not be pathogen free, pathogen indexing is important

excessive exudates the production of exudates by the explant itself is a problem encountered during tissue culture, antioxidant treatment (ascorbic acid) is most effective

tissue proliferation (TP) the formation of gall-like growths on the step of micropropagated plants

habituation the autrophic growth in cultures which had previously required auxin/cytokinin for growth

these are all variations of micropropagated plants:

(a) genetic changes prior to, or during micropropagation, that are the most serious types of aberration because they are permanent and diffucult to detect during the operation, also termed as somaclonal variation

(b) these are temporary changes that disappear as the plant grows, enhanced vigor is common, change in developmental stage, and enhanced branching

(c) changes in gene expression but no change in the gene sequence

choices: epigenetic changes, genetic/chimera variation, transient phenotypic variation

genetic/chimera variation genetic changes prior to, or during micropropagation, that are the most serious types of aberration because they are permanent and diffucult to detect during the operation, also termed as somaclonal variation

transient phenotypic variation these are temporary changes that disappear as the plant grows, enhanced vigor is common, change in developmental stage, and enhanced branching

epigenetic variation changes in gene expression but no change in the gene sequence

(a) the most important means for clonal regeneration, stem and leaf-bud aim for adventitious roots whereas root and leaf aim for adventitious root and shoot

(b) the successive growth sequences, designated by the number of years the plant has grown from propagule or seed

(c) the phases of development that the seedling plant undergoes from embryonic to juvenile to intermediate to adult

choices: chronological age or ontogenetic aging, and cutting propagation

cutting propagation the most important means for clonal regeneration, stem and leaf-bud aim for adventitious roots whereas root and leaf aim for adventitious root and shoot

chronological age the successive growth sequences, designated by the number of years the plant has grown from propagule or seed

ontogenetic aging the phases of development that the seedling plant undergoes from embryonic to juvenile to intermediate to adult

physiologically mature material is desirable for propagation

(a) plants that are maintained for the purpose of harvesting cuttings or grafting wood for vegetative propagation

(b) hedging, pruning, stooling aim to maintain high rooting potential

(c) forcing juvenile growth from sphaeroblasts, wartlike protuberances, and conductive tissues found on trunk or branches

choices: inducing rejuvenation, stock plants, strategies for stock plants

stock plants plants that are maintained for the purpose of harvesting cuttings or grafting wood for vegetative propagation

strategies for stock plants hedging, pruning, stooling aim to maintain high rooting potential

inducing rejuvenation forcing juvenile growth from sphaeroblasts, wartlike protuberances, and conductive tissues found on trunk or branches

(a) the process of formation of an embryo as a result of double fertilization of the ovule

(b) photoperiod favors vegetative growth and suppresses reproductive growth

choices: photomorphogenic effect or zygote embryo formation

zygote embryo formation the process of formation of an embryo as a result of double fertilization of the ovule

photomorphogenic effect photoperiod favors vegetative growth and suppresses reproductive growth

(a) the total exclusion of light

(b) localized light exclusion, only excluding light on a portion of a stem that will be used as the cutting base

(c) any stock-plant grown under reduced light conditions

choices: shading, etiolation, banding

etiolation the total exclusion of light

banding localized light exclusion, only excluding light on a portion of a stem that will be used as the cutting base

shading any stock-plant grown under reduced light conditions

(a) cutting around the stem to go through the bark, cortex and phloem, it is the removal of park by wounding/bending/tying

(b) increased photosynthesis, higher relative growth, greater lateral branching of stock plants = increased cutting yields

(c) no regulatory role but positive correlation

choices: carbohydrates, carbon dioxide enrichment, gridling

girdling cutting around the stem to go through the bark, cortex and phloem, it is the removal of park by wounding/bending/tying

carbon dioxide enrichment increased photosynthesis, higher relative growth, greater lateral branching of stock plants = increased cutting yields

carbohydrates no regulatory role but positive correlation

when should you take cuttings from the following plants:

• dedicious species

• semi-hardwood

• softwood

• evergreen

  • broadleaf

  • narrowleaf

• tropical

choices: throughout the year, spring/fall, spring/early-summer, late-fall/late-winter, early/mid-summer, before buds force out

• dedicious species - before buds force out

• semi-hardwood - early/mid-summer

• softwood - spring/early-summer

• evergreen

  • broadleaf - spring/fall

  • narrowleaf - late-fall/late-winter

  • tropical - throughout the year

remember, we want to maintain the plants’ momentum of growth

(a) segments of shoots containing lateral or terminal buds

(b) most common cut, straight across

(c) a small section of older wood included at the base of the cutting

(d) an entire section of older wood stem is included

choices: mallet, straight, heel, stem cuttings

stem cuttings segments of shoots containing lateral or terminal buds

straight most common cut, straight across

heel a small section of older wood included at the base of the cutting

mallet an entire section of older wood stem is included

(a) must include two nodes, cut below a node and 1.5-2.5cm above the node, least expensive and easiest method of vegetative propagation, not readily perishable, easy to ship, slow rooting ability

(b) 3-6 inches of cutting, auxin is 1000-3000 mg/L, apical and basal portions used

(c) 3-5 inches of cutting, auxin is 500-1250 mg/L, short life-span and shipping constraingts, lower leaves are removed and upper leaves remain, fast-rooting ability

(d) 3-5 inchest of cutting, humidity is crucial, bottom heat is helpful, auxin is not necessary, fast rooting ability

choices: softwood cutting, hardwood cutting, herbaceous cutting, semi-hardwood cutting

hardwood cutting must include two nodes, cut below a node and 1.5-2.5cm above the node, least expensive and easiest method of vegetative propagation, not readily perishable, easy to ship, slow rooting ability

semi-hardwood cutting 3-6 inches of cutting, auxin is 1000-3000 mg/L, apical and basal portions used

softwood cutting 3-5 inches of cutting, auxin is 500-1250 mg/L, short life-span and shipping constraingts, lower leaves are removed and upper leaves remain, fast-rooting ability

herbaceous cutting 3-5 inchest of cutting, humidity is crucial, bottom heat is helpful, auxin is not necessary, fast rooting ability

these are the three systems of hardwood cutting:

(a) regions with mild winters, allowed to grow one season then harvested, used for slower-rooting species

(b) collected in late-fall/winter, stored in cold and moist conditions so budding does not occur, put in flats with intermittent mist

(c) collected in call/winter, basal ends need IBA, remove at signs of root formation, used for difficult to root species

choices: spring planting, direct fall planting, initiation of rooting with bottom heat

direct fall planting regions with mild winters, allowed to grow one season then harvested, used for slower-rooting species

spring planting collected in late-fall/winter, stored in cold and moist conditions so budding does not occur, put in flats with intermittent mist

initiation of rooting with bottom heat collected in call/winter, basal ends need IBA, remove at signs of root formation, used for difficult to root species

(a) leaf blade with/without petiole is used to get a new plant, adventitious buds (shoots) and roots form at the base, original leaf will not be part of new plant

(b) whole leaf + axillary bud = short stem section, only adventitious roots need to form, high humidity is essential, auxin is needed

(c) root pieces taken during winter and early spring, adventitious shoot and root system

choices: root cutting, leaf cutting and leaf+bud cutting

leaf cutting leaf blade with/without petiole is used to get a new plant, adventitious buds (shoots) and roots form at the base, original leaf will not be part of new plant

leaf+bud cutting whole leaf + axillary bud = short stem section, only adventitious roots need to form, high humidity is essential, auxin is needed

root cutting root pieces taken during winter and early spring, adventitious shoot and root system

small roots (1/4” - 1”) planted horizontally and large roots planted vertically (>1”)

how to handle root cuttings:

(a) 1-2 inches, horizontal in flats, moist and shaded in greenhouse, hot bed, or heated polyhouse

(b) 2-3 inches, vertically, warm and moist, in greenhouse or hotbeds

(c) 2-6 inches, planted vertically, stored at 40 degrees for three weeks in fields

choices: fleshy roots, large roots, small delicate roots

small, delicate roots 1-2 inches, horizontal in flats, moist and shaded in greenhouse, hot bed, or heated polyhouse

fleshy roots 2-3 inches, vertically, warm and moist, in greenhouse or hotbeds

large roots 2-6 inches, planted vertically, stored at 40 degrees for three weeks in fields

these are the different types of pruning:

(a) severely cut back to their base

(b) cut back to ½ their size annually

(c) plants are cut back to 1/3 to ½ of the previous annual shoot

(d) removing tips of shoots or normal removing of cuttings

(e) maintain the hedge form

(f) spring pruning + june pruning, delays cutting harvest till fall

choices: double pruning, modified stooling', head pruning, hedging, light pruning, moderate pruning

modified stooling severely cut back to their base

hard pruning cut back to ½ their size annually

moderate pruning plants are cut back to 1/3 to ½ of the previous annual shoot

light pruning removing tips of shoots or normal removing of cuttings

hedging maintain the hedge form

double pruning spring pruning + june pruning, delays cutting harvest till fall

(a) used to promote rooting, stimulating active cell division, ethylene evolution, improving contact layer, removing any anatomical barriers

(b) increases the percentage of cuttings that form roots, faster root initiations, increase rooting uniformity

choices: auxin treatment or wounding

wounding used to promote rooting, stimulating active cell division, ethylene evolution, improving contact layer, removing any anatomical barriers

auxin treatment increases the percentage of cuttings that form roots, faster root initiations, increase rooting uniformity

match the concentration of auxin to the cutting type:

(a) no need

(b) 500-1250 mg/L IBA/NAA

(c) 1000-3000 mg/L IBA/NAA, 5000 max

(d) 2500-5000 mg/L IBA/quick dip, 10000 max for recalcitrant species

choices: softwood, semi-hardwood, hardwood, herbaceous

herbaceous cutting no need

softwood cutting 500-1250 mg/L IBA/NAA

semi-hardwood cuttings 1000-3000 mg/L IBA/NAA, 5000 max

hardwood cuttings 2500-5000 mg/L IBA/quick dip, 10000 max for recalcitrant species

(a) atmosphere conductive to low water loss and maintenance of tugor in leaves

(b) ample but nor excessive light, clean, moist, well aerated, well drained

(c) 18-25C for temperate species and 7C higher for the most tropical species

choices: light, rooting media temp., light

humidity atmosphere conductive to low water loss and maintenance of tugor in leaves

light ample but nor excessive light, clean, moist, well aerated, well drained

rooting media temperature 18-25C for temperate species and 7C higher for the most tropical species

(a) stress adaptation process, gradually acclimating rooted cuttings from high humidity conditions to reduce humidity

(b) trough systems are a convenient method for converting standard benched to a water containment system, more economical, less maintenance

(c) particle size of water is fine and water will not condense the surfaces of the cutting

(d) open mist and enclosed mist system

(e) outdoors: low polyethylene tunnels, cold frames, hot frames inside: contact polyethylene systems

choices: enclosed systems, fog systems, sub-irrigation system, hardening off, intermittent mist system

hardening off stress adaptation process, gradually acclimating rooted cuttings from high humidity conditions to reduce humidity

sub-irrigation system trough systems are a convenient method for converting standard benched to a water containment system, more economical, less maintenance

fog system particle size of water is fine and water will not condense the surfaces of the cutting

intermittent mist system open mist and enclosed mist system

enclosed systems outdoors: low polyethylene tunnels, cold frames, hot frames inside: contact polyethylene systems