Reproduction systemReproduction system

Reproduction systems in Reproduction systems in plantsplants

• Seed propagated speciesSeed propagated species– self-pollinated self-pollinated – cross pollinatedcross pollinated– self- and cross pollinatedself- and cross pollinated

• Vegetatively propagated speciesVegetatively propagated species

Sexual reproductionSexual reproductionIn animals: It’s easy because you have In animals: It’s easy because you have

separate male and female individuals.separate male and female individuals.In flowering plants: Not so easy, In flowering plants: Not so easy,

because most flowers have because most flowers have bothboth male male and female parts in them, called and female parts in them, called perfect flowersperfect flowers..

So flowering plants have evolved So flowering plants have evolved special ways to insure special ways to insure out-breeding/out-crossing – and to out-breeding/out-crossing – and to prevent inbreeding.prevent inbreeding.

Plant ReproductionPlant Reproduction

Plant Reproduction: male gametophytePlant Reproduction: male gametophyte

•Cells within anther undergo meiosis

•Produce 4 spores

•Each spore undergoes mitosis

•Results in pollen grain containing 2 sperm

Plant Reproduction: female Plant Reproduction: female gametophytegametophyte

• Within ovule, a cell undergoes meiosis

• Produces 4 spores

• 1 spore undergoes mitosis

• Produces embryo sac

• Egg is contained within embryo sac

Plant Plant ReproductionReproduction

•During pollination, pollen lands on stigma

•Sperm travels down pollen tube

•1 sperm fertilizes egg

•The other contributes to formation of tissue that will provide nourishment to embryo

Ovule develops into seedOvule develops into seed

Basic Terms• Outbreeding

Sexual reproduction between individuals (cross-pollination). (It involves two individual plants)

• InbreedingSexual reproduction within an individual (self-pollination). (It involves one individual plant)

• Sexual ReproductionThe sexual process is a mechanism to bring about gene recombination.

Recombination is the chief source of hereditary variation and provides the raw materials for species to adapt to changing environmental conditions.

Function of flowerFunction of flowerattract pollinators with colorful petals, scent, attract pollinators with colorful petals, scent,

nectar and pollennectar and pollen

Carpel/

Overview of floral organsOverview of floral organs

Reproductive floral organs: femaleReproductive floral organs: femaleCarpel Carpel or or pistilpistil – female – female

reproductive organs; reproductive organs; contains:contains:

• Stigma – Stigma – is where pollen sticks is where pollen sticks toto

• StyleStyle – is the long tube that – is the long tube that connects stigma to ovaryconnects stigma to ovary

• Ovary Ovary – enlarged structure at – enlarged structure at the base of carpel/pistil where the base of carpel/pistil where the ovules are located; it will the ovules are located; it will become the fruit.become the fruit.

• Ovules Ovules – contains female – contains female gametophyte, becomes gametophyte, becomes the seedthe seed

• Plants have style!Plants have style!

carpel or pistil

ovary

Reproductive floral organs: maleReproductive floral organs: male

StamenStamen – male floral – male floral organ, consists of:organ, consists of:

Anther Anther – part of the – part of the stamen that produces stamen that produces pollenpollen

FilamentFilament – stalk-like – stalk-like structure that holds antherstructure that holds anther

PollenPollen – immature male – immature male gametophytegametophyte

Non-reproductive floral organsNon-reproductive floral organsPetalsPetals – whorl of flower organs – whorl of flower organs

that are often brightly colored to that are often brightly colored to attract pollinatorsattract pollinators

CorollaCorolla – whorl of petals – whorl of petals in a flowerin a flower

Sepals – whorl of leaf-like organs outside the corolla; help protect the unopened flower bud.

Calyx – whorl of sepals in a flower

Tepals – when sepals and petals look the same

Pollination and FertilizationPollination and Fertilization

• Pollen contains TWO nuclei: a Pollen contains TWO nuclei: a spermsperm nucleus and nucleus and tubetube nucleus nucleus

• Sperm nucleus is protected in gametophyte tissue Sperm nucleus is protected in gametophyte tissue (pollen can travel in the air)(pollen can travel in the air)

Pollination and FertilizationPollination and Fertilization For pollen sperm to successfully fertilize the egg, there must For pollen sperm to successfully fertilize the egg, there must

be be pollinationpollination: a method to get the pollen from the male : a method to get the pollen from the male anther to the stigma.anther to the stigma.

Pollen sticks to the stigma, starts growing a pollen tubePollen sticks to the stigma, starts growing a pollen tube FertilizationFertilization begins when begins when

tube begins to grow tube begins to grow toward the eggtoward the egg

Double FertilizationDouble Fertilization• Double fertilizationDouble fertilization occurs: One sperm nucleus occurs: One sperm nucleus

(1n) fertilizes the egg, producing a (1n) fertilizes the egg, producing a zygotezygote (2n) (2n) which becomes the plant which becomes the plant embryo embryo inside the seedinside the seed

• Another sperm nucleus fuses with the polar nuclei, Another sperm nucleus fuses with the polar nuclei, resulting in a triploid resulting in a triploid endospermendosperm (3n) (3n)

• Endosperm is a source of food for the young embryo.Endosperm is a source of food for the young embryo.

Endosperm

The seedThe seed

Parts of the seed:Parts of the seed:

• Seed CoatSeed Coat offers offers protectionprotection

• EndospermEndosperm supplies food for supplies food for the seedthe seed

• EmbryoEmbryo is the is the young plantyoung plant

Hermaphroditic FlowersHermaphroditic Flowers

• Self-compatible (SC)Self-compatible (SC)– Capable of self-Capable of self-

fertilization or cross-fertilization or cross-fertilizationfertilization

• Self-incompatible Self-incompatible (SI)(SI)– Only capable of Only capable of

cross-fertilizationcross-fertilization– Inability of Inability of

hermaphroditic plant hermaphroditic plant to produce zygotes to produce zygotes w/ self pollenw/ self pollen

Autogamy Autogamy

• Self-fertilizationSelf-fertilization

• Pollen transfer Pollen transfer within or among within or among flowers of same flowers of same individualindividual

• ~25% of plant taxa~25% of plant taxa

Advantages of AutogamyAdvantages of Autogamy

• Insures seed set in absence of Insures seed set in absence of pollinators.pollinators.

• Overcomes sterility.Overcomes sterility.

• Selectively advantageous by Selectively advantageous by transmitting both sets of genes to transmitting both sets of genes to offspring.offspring.– Well-adapted genotypes preserved.Well-adapted genotypes preserved.

• Only single colonizing individual needed.Only single colonizing individual needed.

Disadvantages of AutogamyDisadvantages of Autogamy

• Decreases genetic variability.Decreases genetic variability.

• Inability to adapt to changing Inability to adapt to changing conditions.conditions.

• Increases inbreeding depression.Increases inbreeding depression.– Reduces heterozygosity and increases Reduces heterozygosity and increases

homozygosity of deleterious alleles.homozygosity of deleterious alleles.– More uniform populations.More uniform populations.

Cleistogamy

• Flowers never open and Flowers never open and only capable of self-only capable of self-fertilization in bud.fertilization in bud.

• Inconspicuous, bud-like Inconspicuous, bud-like apetalous flowers that apetalous flowers that form directly into seed form directly into seed capsules.capsules.

• Has evolved Has evolved independently multiple independently multiple timestimes– throughout the throughout the

angiosperms, including angiosperms, including some basal lineages.some basal lineages.

• 488 species, across 212 488 species, across 212 genera and 49 families.genera and 49 families.– Violaceae, Fabaceae, Violaceae, Fabaceae,

PoaceaePoaceae

Outbreeding (Cross-pollination)

•Advantages:

•Disadvantages:

Increases genetic variability

Strong evolutionary potential Adaptation to changing conditions

Successful long-term

Can destroy well-adapted genotypes

Relies on effective cross-pollination, seed dispersal and establishment

How do plants get pollen from one How do plants get pollen from one plant to another?plant to another?

• Because plants are rooted in Because plants are rooted in the ground, they must use the ground, they must use different strategies:different strategies:

WIND POLLINATIONWIND POLLINATION: : Gymnosperms and some Gymnosperms and some

flowering plants (grasses, flowering plants (grasses, trees) trees) use wind pollination.use wind pollination.

Flowers are small, grouped Flowers are small, grouped togethertogether

Not a very efficient methodNot a very efficient method(too chancy and wasteful)(too chancy and wasteful)

ANIMALSANIMALSMany flowering plants rely on animals for Many flowering plants rely on animals for cross-pollination:cross-pollination:

InsectsInsects – bees, wasps, flies, butterflies, moths – bees, wasps, flies, butterflies, mothsBirdsBirds – hummingbirds, honey creepers – hummingbirds, honey creepersMammalsMammals – bats, mice, monkeys – bats, mice, monkeys

Even some reptiles and amphibiansEven some reptiles and amphibians!!

CoevolutionCoevolution• CoevolutionCoevolution

interactions between two different species as interactions between two different species as selective forces on each other, resulting in selective forces on each other, resulting in adaptations that increase their adaptations that increase their interdependency.interdependency.

• Animal-flowering plant interaction is a classic Animal-flowering plant interaction is a classic example of coevolution:example of coevolution:1. Plants evolve elaborate methods to attract animal1. Plants evolve elaborate methods to attract animal

pollinatorspollinators

2. Animals evolved specialized body parts and 2. Animals evolved specialized body parts and behaviors behaviors

that aid plant pollinationthat aid plant pollination

A word about pollen…A word about pollen…

• The shape and form of The shape and form of pollen is related to its pollen is related to its method of pollination…method of pollination…

Insect-pollinated speciesInsect-pollinated specieshave sticky of barbedhave sticky of barbedpollen grainspollen grains

Wind-pollinated speciesWind-pollinated speciesis lightweight, small andis lightweight, small andsmooth (corn pollen)smooth (corn pollen)

Palynology: the study of pollenPalynology: the study of pollen

• Palynology is useful in many fields:Palynology is useful in many fields:Petroleum geologyPetroleum geology – fossil pollen can – fossil pollen can

determine if a field will have oil-rich depositsdetermine if a field will have oil-rich depositsArcheologyArcheology – studying ancient pollen – studying ancient pollen

samples, archeologists can determine samples, archeologists can determine agricultural practices, diet, etc.agricultural practices, diet, etc.

Anthropology Anthropology – uses of pollen in rituals– uses of pollen in rituals Criminology Criminology – to determine the whereabouts – to determine the whereabouts

of an individual, examine pollen clinging to of an individual, examine pollen clinging to clothesclothes

Aerobiology Aerobiology – to determine what plants – to determine what plants cause hay fever and allergic reactions – in cause hay fever and allergic reactions – in landscapinglandscaping

Animal pollinators: BeesAnimal pollinators: Bees• BeesBees – the most – the most

important group of important group of flower pollinatorsflower pollinators

They live on the nectar and They live on the nectar and feed feed larvae, also eat the pollen.larvae, also eat the pollen.

Bees are guided by sight Bees are guided by sight andandsmellsmell

See See yellowyellow and and blueblue colors, colors,also ultraviolet light (not also ultraviolet light (not red)red)

Flowers have Flowers have “honey guides” “honey guides” and bee landing and bee landing platforms..platforms..

Butterflies and mothsButterflies and moths• Also guided by sight and Also guided by sight and

smellsmell

• Butterflies can see Butterflies can see redred and and orangeorangeflowersflowers

• Usually shaped as a long tube Usually shaped as a long tube

because of insect’sbecause of insect’sproboscis – to get nectarproboscis – to get nectar

• Moth-pollinated flowersMoth-pollinated flowersare usually white or pale,are usually white or pale,with sweet, strong odor – with sweet, strong odor – for night pollination.for night pollination.

Flies and beetlesFlies and beetles• Flies like flowers that Flies like flowers that

smellsmelllike dung or rotten meat.like dung or rotten meat.

• Lay their eggs there, but Lay their eggs there, but larvae die due to lack of foodlarvae die due to lack of food

• Beetles pollinate flowersthat are dull in color, buthave very strong odor

BirdsBirds• Birds have a good senseBirds have a good sense

of color, they like yellow orof color, they like yellow orredred flowers…flowers…

• But birds do not have a goodBut birds do not have a goodsense of smell, so bird-pollinatedsense of smell, so bird-pollinatedflowers usually have little odor.flowers usually have little odor.

• Flowers provide fluid nectar inFlowers provide fluid nectar ingreater quantities than insectsgreater quantities than insects

• Hummingbird-pollinated flowersHummingbird-pollinated flowersusually have long, tubular corollausually have long, tubular corolla

• Pollen is large and stickyPollen is large and sticky

Mammals: bats and miceMammals: bats and mice

• Bats pollinate at night,Bats pollinate at night,so flowers are whiteso flowers are white

• Mouse-pollinated flowersMouse-pollinated flowersare usually are usually inconspicuous,inconspicuous,they open at nightthey open at night

Why do animals pollinate plants?Why do animals pollinate plants?• They get a REWARD: food! In They get a REWARD: food! In

exchange for moving their pollen exchange for moving their pollen to another flowerto another flower

• NectarNectar – a sugary solution produced – a sugary solution produced in special flower glands called nectariesin special flower glands called nectaries

• Nectar concentration matches energy Nectar concentration matches energy requirements of the pollinator: bird- requirements of the pollinator: bird- and bee-pollinated flowers have and bee-pollinated flowers have different sugar conc.different sugar conc.

• PollenPollen – is high in protein, some bees – is high in protein, some bees and beetles eat it. and beetles eat it.

• Flowers can produce two kinds of Flowers can produce two kinds of pollen: a normal and a sterile, but pollen: a normal and a sterile, but tasty, kind, for the insect.tasty, kind, for the insect.

Getting the pollinator’s attentionGetting the pollinator’s attention

• Plants advertise their pollen and Plants advertise their pollen and nectar rewards withnectar rewards with

• Colors – bees see Colors – bees see blueblue, , yellowyellow, , UV; while birds see UV; while birds see redred. Bats don’t . Bats don’t see well, so flowers are white.see well, so flowers are white.

• Nectar or honey guides – Nectar or honey guides – a visual guide for pollinator a visual guide for pollinator to locate the reward (pansy flower)to locate the reward (pansy flower)

• Aromas – for insects, nectar.Aromas – for insects, nectar.Can also be carrion or dung smellCan also be carrion or dung smell

Plant MimicryPlant Mimicry• Some plants take advantage Some plants take advantage

of the sex drive of certain of the sex drive of certain insects…insects…

• Certain orchids look like Certain orchids look like female wasps, and even female wasps, and even smell like them!smell like them!

• Males try to mate with them,Males try to mate with them,and in the process theyand in the process theypollinate the plantpollinate the plant

• The orchid gets pollinated,The orchid gets pollinated,but the male wasp only getsbut the male wasp only getsfrustrated!frustrated!

Selfers vs. Outcrossers

• SCSC• Small flowers (few)Small flowers (few)• Unscented flowersUnscented flowers• Nectaries & nectar Nectaries & nectar

guides absentguides absent• Maturation of Maturation of

reproductive partsreproductive parts– Anthers near stigmaAnthers near stigma– Style includedStyle included

• All fruits matureAll fruits mature• Low pollen/ovule ratioLow pollen/ovule ratio

• SI or SCSI or SC• Large showy flowers Large showy flowers

(many)(many)• Scented flowersScented flowers• Nectaries & nectar Nectaries & nectar

guides presentguides present• Differential maturation Differential maturation

of reproductive partsof reproductive parts– Anthers far from stigmaAnthers far from stigma– Stigma well-exsertedStigma well-exserted

• Only some fruits matureOnly some fruits mature• High pollen/ovule ratioHigh pollen/ovule ratio

Strategies to Prevent Self-Strategies to Prevent Self-fertilizationfertilization

Strategies to avoid self-pollinationStrategies to avoid self-pollination

Perfect flowers have both male and Perfect flowers have both male and female organs, so plants have female organs, so plants have strategies to avoid self-pollination:strategies to avoid self-pollination:

1. 1. TimingTiming – male and female – male and female structures mature at different timesstructures mature at different times

2. 2. MorphologicalMorphological – structure of– structure ofmale and female organs preventsmale and female organs preventsself-pollination (imperfect flower)self-pollination (imperfect flower)

3. 3. BiochemicalBiochemical – chemical on – chemical on surface of pollen and stigma/stylesurface of pollen and stigma/stylethat prevent pollen tube that prevent pollen tube germinationgermination

on the same flower (incompatibleon the same flower (incompatible))

Physical Separation of Physical Separation of Reproductive PartsReproductive Parts

• Within flowersWithin flowers • Among flowersAmong flowers

Herkogamy:Herkogamy:Pollination by the neighbor individual, population or Pollination by the neighbor individual, population or speciesspecies

HeterostylyHeterostylyA polymorphism among flowers that ensures A polymorphism among flowers that ensures

cross-fertilization through pollination by visiting cross-fertilization through pollination by visiting insectsinsects

Flowers have anthers and styles of different Flowers have anthers and styles of different lengthlength

Flowers in different individuals of the same species Flowers in different individuals of the same species having 2 or 3 different style lengthshaving 2 or 3 different style lengths

– With stamen lengths varying inverselyWith stamen lengths varying inversely

• DistylyDistyly

• TristylyTristyly

DistylyDistyly

• 2 floral morphs.2 floral morphs.

• ““Thrum” flower Thrum” flower – long filaments with long filaments with

short stylesshort styles

• ““Pin” flowerPin” flower– short filaments with short filaments with

long styleslong styles

• Only pollinations Only pollinations between different between different floral morphs are floral morphs are successful.successful.

• E.g.: E.g.: PrimulaPrimula

TristylyTristyly

• 3 floral morphs3 floral morphs

• Style long, stamens Style long, stamens short and mediumshort and medium

• Style medium, Style medium, stamens short and stamens short and longlong

• Style short, Style short, stamens medium stamens medium and longand long

Physical Separation of Reproductive PartsPhysical Separation of Reproductive Parts

• Unisexual flowersUnisexual flowers– Staminate and Staminate and

carpellate flowerscarpellate flowers

• MonoecyMonoecy

• DioecyDioecy

MonoecyMonoecy

• Common in wind-Common in wind-pollinated plants.pollinated plants.

• Common in Common in temperate regions.temperate regions.

• Self-pollination Self-pollination possible but less possible but less likely.likely.

DioecyDioecy

• 4% of angiosperms4% of angiosperms– Scattered throughoutScattered throughout

• Common in tropical Common in tropical regions and oceanic regions and oceanic islandsislands

• Gen small fl sizeGen small fl size

• 100% out-crossing, 100% out-crossing, but inefficientbut inefficient

• Often controlled by Often controlled by sex chromosomessex chromosomes– SileneSilene

Polygamous FlowersPolygamous Flowers

• Both bisexual and unisexual flowers on the same Both bisexual and unisexual flowers on the same plant.plant.– Androdioecy = bisexual and staminate individuals in a population.Androdioecy = bisexual and staminate individuals in a population.– Andromonoecy = bisexual and staminate flowers on same individual.Andromonoecy = bisexual and staminate flowers on same individual.

• Euphorbia, SolanumEuphorbia, Solanum

– Gynodioecy = bisexual and carpellate individuals in a population.Gynodioecy = bisexual and carpellate individuals in a population.• Sidalcea hendersonii, SileneSidalcea hendersonii, Silene

– Gynomonoecy = bisexual and carpellate flowers on same individual.Gynomonoecy = bisexual and carpellate flowers on same individual.• Silene, SolidagoSilene, Solidago

– Polygamodioecy = some plants with bisexual and staminate flowers & Polygamodioecy = some plants with bisexual and staminate flowers & some plants with bisexual and carpellate flowers in a population.some plants with bisexual and carpellate flowers in a population.

– PolygamomonoecyPolygamomonoecy = bisexual, staminate, and carpellate flowers on = bisexual, staminate, and carpellate flowers on same individual.same individual.

Evolution of DioecyEvolution of Dioecy• From hermaphroditismFrom hermaphroditism

– Vestigial sex organsVestigial sex organs– Few families entirely dioeciousFew families entirely dioecious

• From monoecyFrom monoecy• From SCFrom SC

– Within groups that have lost Within groups that have lost original GSI systemoriginal GSI system

• From distylyFrom distyly– Unequal pollen flow & gender Unequal pollen flow & gender

functionfunction– Change in pollinator frequencyChange in pollinator frequency– Non-functional anthers at low Non-functional anthers at low

level in female flowerslevel in female flowers– Non-functional pistil in male Non-functional pistil in male

flowersflowers

Temporal Separation of Reproductive Parts Temporal Separation of Reproductive Parts (Dichogamy)(Dichogamy)

• ProtandryProtandry– Anthers release Anthers release

pollen before stigma pollen before stigma receptivereceptive

– Common in insect-Common in insect-pollinated plantspollinated plants

• Geranium Geranium maculatummaculatum– 1st day flower1st day flower– 2nd day flower2nd day flower

Temporal Separation of Reproductive Parts Temporal Separation of Reproductive Parts (Dichogamy)(Dichogamy)

• ProtogynyProtogyny– Stigma receptive Stigma receptive

before pollen before pollen releaserelease

– Less common than Less common than protandryprotandry

• Magnolia Magnolia grandifloragrandiflora– 1st day flower1st day flower– 2nd day flower2nd day flower

GeitonogamyGeitonogamy

• Self pollination between different flowers Self pollination between different flowers on same plant.on same plant.

Asexual Asexual propagation...propagation...Asexual Asexual propagation...propagation...

“vegetative reproduction, i.e., multiplication that does not involve the seed cycle - clonal propagation.”

“vegetative reproduction, i.e., multiplication that does not involve the seed cycle - clonal propagation.”

Clone...Clone...Clone...Clone...

A genetically identical assemblage of individuals produced from a plant entirely by vegetative means.

Hartmann and Kester

A genetically identical assemblage of individuals produced from a plant entirely by vegetative means.

Hartmann and Kester

Benefits of clonal Benefits of clonal propagation...propagation...Benefits of clonal Benefits of clonal propagation...propagation...

•Some plants produce few (if any) viable seeds.Some plants produce few (if any) viable seeds.

•Clonal progeny are highly uniform in all Clonal progeny are highly uniform in all characters.characters.

•Outcrossing plants produce highly variable Outcrossing plants produce highly variable progeny.progeny.

•Plants may have extended juvenile period.Plants may have extended juvenile period.

•Cloning allows for combining genotypes in one Cloning allows for combining genotypes in one plant.plant.

•Seeds may have lengthy and complex Seeds may have lengthy and complex dormancies.dormancies.

•Some plants produce few (if any) viable seeds.Some plants produce few (if any) viable seeds.

•Clonal progeny are highly uniform in all Clonal progeny are highly uniform in all characters.characters.

•Outcrossing plants produce highly variable Outcrossing plants produce highly variable progeny.progeny.

•Plants may have extended juvenile period.Plants may have extended juvenile period.

•Cloning allows for combining genotypes in one Cloning allows for combining genotypes in one plant.plant.

•Seeds may have lengthy and complex Seeds may have lengthy and complex dormancies.dormancies.

Cutting PropagationCutting Propagation– Produce Produce adventitious rootsadventitious roots.. Cells near the wound must Cells near the wound must dedifferentiatededifferentiate and and

create a new meristematic region.create a new meristematic region.

CuttingCutting

•

Cutting propagation...Cutting propagation...Cutting propagation...Cutting propagation...

•Cutting capable of regenerating roots (or Cutting capable of regenerating roots (or shoots) from adventitious meristem.shoots) from adventitious meristem.

•Cuttings defined by size and location on Cuttings defined by size and location on parent plant:parent plant:

– stem tipstem tip– nodalnodal– rootroot– leafleaf

•Cuttings also defined by condition of Cuttings also defined by condition of growth:growth:– softwood, semihardwood, hardwoodsoftwood, semihardwood, hardwood

•Cutting capable of regenerating roots (or Cutting capable of regenerating roots (or shoots) from adventitious meristem.shoots) from adventitious meristem.

•Cuttings defined by size and location on Cuttings defined by size and location on parent plant:parent plant:

– stem tipstem tip– nodalnodal– rootroot– leafleaf

•Cuttings also defined by condition of Cuttings also defined by condition of growth:growth:– softwood, semihardwood, hardwoodsoftwood, semihardwood, hardwood

Conditions required for rooting Conditions required for rooting cuttings...cuttings...Conditions required for rooting Conditions required for rooting cuttings...cuttings...

•Hardwood and root cuttings require well Hardwood and root cuttings require well drained medium, but little moisture control.drained medium, but little moisture control.

•Leafy cuttings require high humidity to Leafy cuttings require high humidity to prevent excessive dehydration:prevent excessive dehydration:

– intermittent mist systems.intermittent mist systems.– poly tents or cold frames.poly tents or cold frames.– fog.fog.

•Medium into which cuttings are stuck must be Medium into which cuttings are stuck must be disease free, well drained, and light.disease free, well drained, and light.

•Auxin application now standard treatment.Auxin application now standard treatment.

•Hardwood and root cuttings require well Hardwood and root cuttings require well drained medium, but little moisture control.drained medium, but little moisture control.

•Leafy cuttings require high humidity to Leafy cuttings require high humidity to prevent excessive dehydration:prevent excessive dehydration:

– intermittent mist systems.intermittent mist systems.– poly tents or cold frames.poly tents or cold frames.– fog.fog.

•Medium into which cuttings are stuck must be Medium into which cuttings are stuck must be disease free, well drained, and light.disease free, well drained, and light.

•Auxin application now standard treatment.Auxin application now standard treatment.

Examples of cutting Examples of cutting propagation...propagation...Examples of cutting Examples of cutting propagation...propagation...

Species Cutting Type

African violet, begonia leaf cuttings

Many woody shrubs stem tip cuttings (softwood)

brambles root cuttings

Willow, poplars dormant hardwood cuttings

Species Cutting Type

African violet, begonia leaf cuttings

Many woody shrubs stem tip cuttings (softwood)

brambles root cuttings

Willow, poplars dormant hardwood cuttings

Grafting and budding...Grafting and budding...Grafting and budding...Grafting and budding...

•Can graft scion cultivar onto size controlling Can graft scion cultivar onto size controlling rootstock.rootstock.

•Many difficult to root plants are graft compatible.Many difficult to root plants are graft compatible.

•Grafting defined by season and type of tissue.Grafting defined by season and type of tissue.– budding (T-budding, inverted T, patch)budding (T-budding, inverted T, patch)– wedge, veneer, whip and tongue, cleft, etc.wedge, veneer, whip and tongue, cleft, etc.

•Scion cultivar may be changed on mature trees Scion cultivar may be changed on mature trees (top working)(top working)

•Can graft scion cultivar onto size controlling Can graft scion cultivar onto size controlling rootstock.rootstock.

•Many difficult to root plants are graft compatible.Many difficult to root plants are graft compatible.

•Grafting defined by season and type of tissue.Grafting defined by season and type of tissue.– budding (T-budding, inverted T, patch)budding (T-budding, inverted T, patch)– wedge, veneer, whip and tongue, cleft, etc.wedge, veneer, whip and tongue, cleft, etc.

•Scion cultivar may be changed on mature trees Scion cultivar may be changed on mature trees (top working)(top working)

“The vascular cambium can regenerate the vascular connections between the scion and rootstock resulting in a complete plant composed of more than one genotype.”

“The vascular cambium can regenerate the vascular connections between the scion and rootstock resulting in a complete plant composed of more than one genotype.”

GraftingGrafting

–Segments of different Segments of different plants are connected and plants are connected and induced to grow together induced to grow together as one plant.as one plant.• ScionScion - Top section of a graft. - Top section of a graft.• RootstockRootstock - Bottom section of - Bottom section of

a graft.a graft.

–Successful grafting Successful grafting depends on good contact depends on good contact between the vascular between the vascular cambium of the scion and cambium of the scion and that of the rootstock.that of the rootstock.

Grafted and budded Grafted and budded plants...plants...Grafted and budded Grafted and budded plants...plants...

Species Graft/bud Type

apples chip, T-bud, cleft

conifers side veneer

pecans patch

roses T-bud (shield)

grapes modified wedge

Species Graft/bud Type

apples chip, T-bud, cleft

conifers side veneer

pecans patch

roses T-bud (shield)

grapes modified wedge

Layering...Layering...Layering...Layering...

•Air layeringAir layering - interrupt cambium and cover wound with - interrupt cambium and cover wound with moistened medium.moistened medium. Ficus elastica, MagnoliaFicus elastica, Magnolia

•Simple layeringSimple layering - low hanging branch covered with soil - low hanging branch covered with soil (with or without wounding) - many shrubs(with or without wounding) - many shrubs

•Tip layeringTip layering - tips of plants (brambles) at certain times - tips of plants (brambles) at certain times of year (rat-tail condition) develop roots where they of year (rat-tail condition) develop roots where they touch the soiltouch the soil Blackberries, raspberriesBlackberries, raspberries

•Mound layeringMound layering - soil mounded to cover base of - soil mounded to cover base of specially pruned young tree (also referred to as stool specially pruned young tree (also referred to as stool layering)layering) Apple rootstocksApple rootstocks

•Air layeringAir layering - interrupt cambium and cover wound with - interrupt cambium and cover wound with moistened medium.moistened medium. Ficus elastica, MagnoliaFicus elastica, Magnolia

•Simple layeringSimple layering - low hanging branch covered with soil - low hanging branch covered with soil (with or without wounding) - many shrubs(with or without wounding) - many shrubs

•Tip layeringTip layering - tips of plants (brambles) at certain times - tips of plants (brambles) at certain times of year (rat-tail condition) develop roots where they of year (rat-tail condition) develop roots where they touch the soiltouch the soil Blackberries, raspberriesBlackberries, raspberries

•Mound layeringMound layering - soil mounded to cover base of - soil mounded to cover base of specially pruned young tree (also referred to as stool specially pruned young tree (also referred to as stool layering)layering) Apple rootstocksApple rootstocks

“Layering involves inducing roots on an intact (or nearly so) plant .”“Layering involves inducing roots on an intact (or nearly so) plant .”

Air LayeringAir LayeringAir LayeringAir Layering

LayeringLayering

•

Specialized Structures

Modified Stems

bulb, corm, tuber, rhizome

pseudobulb, runner

Modified Roots

tuberous root

Specialized Structures

Modified Stems

bulb, corm, tuber, rhizome

pseudobulb, runner

Modified Roots

tuberous root

Propagation by specialized Propagation by specialized structures...structures...Propagation by specialized Propagation by specialized structures...structures...

Species Structure

tulip, onion, Easter lily bulb

potato, Jerusalem artichoke tuber

Iris, lily-of-the valley rhizome

Gladiolus, Crocus corm

strawberry, Ajuga runner

Dahlia, sweet potato tuberous root

Species Structure

tulip, onion, Easter lily bulb

potato, Jerusalem artichoke tuber

Iris, lily-of-the valley rhizome

Gladiolus, Crocus corm

strawberry, Ajuga runner

Dahlia, sweet potato tuberous root

Apomixis...Apomixis...Apomixis...Apomixis...

“the development of an embryo within a seed or flowering structure from a source

other than the egg, resulting in the formation of an embryo (sometimes in

addition to the sexual embryo) that is a clone of the maternal parent.

Examples include polyembryony in citrus and crabapples, and the formation of bulbils

in garlic.”

“the development of an embryo within a seed or flowering structure from a source

other than the egg, resulting in the formation of an embryo (sometimes in

addition to the sexual embryo) that is a clone of the maternal parent.

Examples include polyembryony in citrus and crabapples, and the formation of bulbils

in garlic.”

“an exception to the rule of nonclonal embryony.”“an exception to the rule of nonclonal embryony.”

Micropropagation...Micropropagation...Micropropagation...Micropropagation...

•Micropropagation is rapid, continuous, and efficient.Micropropagation is rapid, continuous, and efficient.

•Specialized equipment, facilities, and technically trained personnel are required.Specialized equipment, facilities, and technically trained personnel are required.

•Steps can be taken to obtain and maintain certified pest-free plants.Steps can be taken to obtain and maintain certified pest-free plants.

•Cost effective if large numbers of a given clone are produced.Cost effective if large numbers of a given clone are produced.

•Widely used for orchids, ferns, many interior foliage plants, rootstocks, etc.Widely used for orchids, ferns, many interior foliage plants, rootstocks, etc.

•Micropropagation is rapid, continuous, and efficient.Micropropagation is rapid, continuous, and efficient.

•Specialized equipment, facilities, and technically trained personnel are required.Specialized equipment, facilities, and technically trained personnel are required.

•Steps can be taken to obtain and maintain certified pest-free plants.Steps can be taken to obtain and maintain certified pest-free plants.

•Cost effective if large numbers of a given clone are produced.Cost effective if large numbers of a given clone are produced.

•Widely used for orchids, ferns, many interior foliage plants, rootstocks, etc.Widely used for orchids, ferns, many interior foliage plants, rootstocks, etc.

“Micropropagation has many synonyms - tissue culture, mass propagation, in vitro culture, cloning.”

“Micropropagation has many synonyms - tissue culture, mass propagation, in vitro culture, cloning.”

Plants amenable to Plants amenable to micropropagation...micropropagation...Plants amenable to Plants amenable to micropropagation...micropropagation...

Flowering pot plants Flowering pot plants - - BegoniaBegonia, African violets, orchids, African violets, orchids

Interior foliage plantsInterior foliage plants - ferns, - ferns, Syngonium, Ficus, Syngonium, Ficus, DiffenbachiaDiffenbachia

Woody ornamentalsWoody ornamentals - red maples, - red maples, RhododendronsRhododendrons, , NandinaNandina

Forest treesForest trees - Poplar, birch, loblolly pine - Poplar, birch, loblolly pine

Fruit treesFruit trees - apple, cherry, pear (many rootstocks) - apple, cherry, pear (many rootstocks)

Vegetable cropsVegetable crops - potato, celery, tomato, onion (male - potato, celery, tomato, onion (male sterile)sterile)

Plantation cropsPlantation crops - banana, date palm, coffee - banana, date palm, coffee

Flowering pot plants Flowering pot plants - - BegoniaBegonia, African violets, orchids, African violets, orchids

Interior foliage plantsInterior foliage plants - ferns, - ferns, Syngonium, Ficus, Syngonium, Ficus, DiffenbachiaDiffenbachia

Woody ornamentalsWoody ornamentals - red maples, - red maples, RhododendronsRhododendrons, , NandinaNandina

Forest treesForest trees - Poplar, birch, loblolly pine - Poplar, birch, loblolly pine

Fruit treesFruit trees - apple, cherry, pear (many rootstocks) - apple, cherry, pear (many rootstocks)

Vegetable cropsVegetable crops - potato, celery, tomato, onion (male - potato, celery, tomato, onion (male sterile)sterile)

Plantation cropsPlantation crops - banana, date palm, coffee - banana, date palm, coffee

Types of development Types of development in in vitrovitro......Types of development Types of development in in vitrovitro......

Proliferation of Proliferation of axillary budsaxillary buds from shoot tip cultures. from shoot tip cultures.Differentiation of Differentiation of adventitious shootsadventitious shoots from leaves, from leaves,

stems, or roots.stems, or roots.Formation and proliferation of Formation and proliferation of somatic embryossomatic embryos..Seed germinationSeed germination - orchids. - orchids.Development of Development of haploid plantshaploid plants from anthers or ovules. from anthers or ovules.Protoplast fusion and Protoplast fusion and somatic hybridsomatic hybrid development. development.

Proliferation of Proliferation of axillary budsaxillary buds from shoot tip cultures. from shoot tip cultures.Differentiation of Differentiation of adventitious shootsadventitious shoots from leaves, from leaves,

stems, or roots.stems, or roots.Formation and proliferation of Formation and proliferation of somatic embryossomatic embryos..Seed germinationSeed germination - orchids. - orchids.Development of Development of haploid plantshaploid plants from anthers or ovules. from anthers or ovules.Protoplast fusion and Protoplast fusion and somatic hybridsomatic hybrid development. development.