Unit 6: Vegetative Growth Unit 6: Vegetative Growth and Plant Propagationand Plant Propagation
Chapters 15 &16Chapters 15 &16
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Unit 6 ObjectivesUnit 6 Objectives Understand how stems, leaves, and roots Understand how stems, leaves, and roots
grow, and the coordinated efforts of the plant grow, and the coordinated efforts of the plant to make this happento make this happen
Stages of development, and factors affecting Stages of development, and factors affecting plant growthplant growth
Discuss seed germinationDiscuss seed germination Understand sexual vs. asexual reproduction, Understand sexual vs. asexual reproduction,
and self-fertilization vs. cross-fertilizationand self-fertilization vs. cross-fertilization
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
GrowthGrowth Increase in volume and wt.Increase in volume and wt. Increase cell numbers and sizeIncrease cell numbers and size Primary GrowthPrimary Growth
Occurs in young, herbaceous organsOccurs in young, herbaceous organsIncreases length of shoots and rootsIncreases length of shoots and rootsMonocots and herbaceous dicotsMonocots and herbaceous dicots
Secondary GrowthSecondary GrowthIncreased girthIncreased girthLayers of woody tissueLayers of woody tissue
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Occurs at the apical meristemOccurs at the apical meristem
Seed GerminationSeed Germination Life in a seed is virtually undetectableLife in a seed is virtually undetectable Seed will die if it is not allowed to germinateSeed will die if it is not allowed to germinate Time to germination varies with speciesTime to germination varies with species Six steps to germinationSix steps to germination
Water presenceWater presence
Enzyme activationEnzyme activation
Hydrolysis & catabolism of storage compoundsHydrolysis & catabolism of storage compounds
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Initiation of embryo growthInitiation of embryo growth
Anabolism and formation of new cell structuresAnabolism and formation of new cell structures
EmergenceEmergence 4 environmental factors affecting germination4 environmental factors affecting germination
WaterWater Absorption of water is first step in germinationAbsorption of water is first step in germination A sufficient amount of available water must be present at A sufficient amount of available water must be present at
germination, and must continue to be present after germination, and must continue to be present after growth beginsgrowth begins
Medium for transport, activates enzymes that initiate Medium for transport, activates enzymes that initiate metabolic function, metabolic function,
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
LightLight Can stimulate or inhibit germination, depending on the Can stimulate or inhibit germination, depending on the
speciesspecies
OxygenOxygen Respiration is taking place in all viable seedRespiration is taking place in all viable seed Medium where seed is placed should be loose enough Medium where seed is placed should be loose enough
for oxygen to permeate through the soilfor oxygen to permeate through the soil Reduced oxygen supply can reduce or inhibit Reduced oxygen supply can reduce or inhibit
germinationgermination
HeatHeat Affects the rate and percentage of germinationAffects the rate and percentage of germination Temperature needs for germination also vary w/ speciesTemperature needs for germination also vary w/ species Usually 65-75Usually 65-75º is optimal for most plantsº is optimal for most plants
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Germination begins when:Germination begins when: Mature embryo in the seedMature embryo in the seed Large enough endosperm to sustain growthLarge enough endosperm to sustain growth Sufficient growth regulators to initiate the processSufficient growth regulators to initiate the process
Seeds Lacking True DormancySeeds Lacking True Dormancy Common vegetable seedsCommon vegetable seeds Ready to sprout after plantingReady to sprout after planting All they need is proper moisture and temperatureAll they need is proper moisture and temperature
Seeds w/ True Dormant EmbryosSeeds w/ True Dormant Embryos Thick seed coatThick seed coat
Restricts water access to the seedRestricts water access to the seedScarification – allows thick coated seeds to Scarification – allows thick coated seeds to germinate, usually occurs naturally (How?)germinate, usually occurs naturally (How?)
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Thin Seed CoatThin Seed CoatNo barrier to waterNo barrier to waterDormancy is controlled by another factor (light)Dormancy is controlled by another factor (light)
Insufficient DevelopmentInsufficient DevelopmentEmbryo may have to fully mature before germination Embryo may have to fully mature before germination can occurcan occurEmbryo often has to feed on something else to foster Embryo often has to feed on something else to foster germinationgerminationUsually not viable for long periods of timeUsually not viable for long periods of time
InhibitorsInhibitorsChemical factors that inhibit germinationChemical factors that inhibit germinationSeed must eliminate these chemicals for germination Seed must eliminate these chemicals for germination to occurto occur
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Abscisic Acid – compound present that restricts a Abscisic Acid – compound present that restricts a seed from germinating through winter, seed spends seed from germinating through winter, seed spends entire winter breaking down the acidentire winter breaking down the acidPhenolic Compounds – protect seed until proper Phenolic Compounds – protect seed until proper moisture is present for germination – common in dry moisture is present for germination – common in dry regionsregions
The Germination Process of CornThe Germination Process of CornKernel absorbs waterKernel absorbs waterSeed swells as chemical processes begin to Seed swells as chemical processes begin to prepare for growthprepare for growthActivation of enzymes to break down food reserves Activation of enzymes to break down food reserves needed for growthneeded for growthEndosperm starch is converted to sugarsEndosperm starch is converted to sugars
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Radicle elongates and breaks through the seed Radicle elongates and breaks through the seed coatcoat
Grows in the direction the kernel is pointed (except up)Grows in the direction the kernel is pointed (except up)
Coleoptile emerges from the seedColeoptile emerges from the seed2-5 seminal roots emerge2-5 seminal roots emergeCan occur in 4-5d under optimal conditionsCan occur in 4-5d under optimal conditionsCrown area found 1-1.5” beneath soil surfaceCrown area found 1-1.5” beneath soil surface
Permanent roots developPermanent roots develop If seed is planted deeper the mesocotyl is responsible for If seed is planted deeper the mesocotyl is responsible for
pushing coleoptile through the soil surfacepushing coleoptile through the soil surface
First leaves emerge from the coleoptile after it First leaves emerge from the coleoptile after it emergesemerges
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Time from planting to emergence is most affected Time from planting to emergence is most affected by temperatureby temperature
1 wk. under optimal conditions1 wk. under optimal conditions May be 2-3 wks in cool conditionsMay be 2-3 wks in cool conditions
What other factors can influence emergence?What other factors can influence emergence? The SeedlingThe Seedling
11stst leaf blade has a rounded tip leaf blade has a rounded tipLeaves begin photosynthesis and the plant no Leaves begin photosynthesis and the plant no longer depends on the seed for survivallonger depends on the seed for survivalCrown root system begins to take control from the Crown root system begins to take control from the seed rootsseed roots
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Apical meristem initiates new leaf formationApical meristem initiates new leaf formation Point is below ground until the internodes elongatePoint is below ground until the internodes elongate Aboveground leaves can be destroyed, and additional Aboveground leaves can be destroyed, and additional
leaves can still formleaves can still form
Unless disease occursUnless disease occurs
Hypogeal emergenceHypogeal emergence Growing point remains beneath soil surface for a period Growing point remains beneath soil surface for a period
of time after emergenceof time after emergence
Epigeal emergenceEpigeal emergence Growing point is above soil surface at the time of Growing point is above soil surface at the time of
emergenceemergence
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
RootsRoots 4 functions4 functions
AnchorAnchor
Absorb water and nutrientsAbsorb water and nutrients
Conduct water and nutrientsConduct water and nutrients
Store food materialsStore food materials Root and shoot system tends to stay Root and shoot system tends to stay
balanced to meet plant needsbalanced to meet plant needs
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Shoot GrowthShoot Growth Determinate growthDeterminate growth
Flowering occurs after a certain period of Flowering occurs after a certain period of vegetative growthvegetative growthMost shoot elongation stopsMost shoot elongation stopsCommon in vegetablesCommon in vegetables
Indeterminate growthIndeterminate growthFlower clusters form laterally along the stemFlower clusters form laterally along the stemShoots remain actively growing until stopped by Shoots remain actively growing until stopped by senescence or something elsesenescence or something else
Ex. grapevinesEx. grapevines
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Growth PatternsGrowth Patterns3 classifications:3 classifications:
AnnualsAnnualsComplete life cycle in less than 1 yr.Complete life cycle in less than 1 yr.Shoot growth in continual until senescenceShoot growth in continual until senescenceFlowering, fruit, and seed production occurs in the Flowering, fruit, and seed production occurs in the summersummerHerbaceousHerbaceous
BiennialsBiennialsLife cycle in two growing seasons, longer than 1 yr Life cycle in two growing seasons, longer than 1 yr but not necessarily 2 yrsbut not necessarily 2 yrsStored energy from 1Stored energy from 1stst yr used in reproduction in 2 yr used in reproduction in 2ndnd yryr
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Ex. Celery, asparagus, sugar beetsEx. Celery, asparagus, sugar beetsLimited stem growth in first seasonLimited stem growth in first seasonDormant winter periodDormant winter periodFlowering, fruit, and seed production during second Flowering, fruit, and seed production during second seasonseasonSenescence and death follow soon after productionSenescence and death follow soon after productionHerbaceousHerbaceous
PerennialsPerennialsContinue growth for 2+ yrsContinue growth for 2+ yrsVegetative growth during and after reproductive Vegetative growth during and after reproductive phasephaseEx. Bermuda grass, shrubs, treesEx. Bermuda grass, shrubs, treesShoot growth resumes each springShoot growth resumes each springHerbaceous or woodyHerbaceous or woody
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Phase ChangesPhase Changes JuvenilityJuvenility
Plant may have a different appearancePlant may have a different appearance
Inability to form flowers during this phaseInability to form flowers during this phase
Length varies from days to yearsLength varies from days to years Most crops vary amount of daysMost crops vary amount of days Trees can have 30-40 yr juvenile stagesTrees can have 30-40 yr juvenile stages
MaturityMaturityAble to produce flowers, fruit, and seedsAble to produce flowers, fruit, and seeds
May have different appearanceMay have different appearance
May last days to yearsMay last days to years
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
FloweringFlowering Days to flowering varies w/ speciesDays to flowering varies w/ species Can be induced by environmental controlsCan be induced by environmental controls Pollination and fertilization followPollination and fertilization follow
Senescence & DeathSenescence & DeathTerminal, irreversible deteriorating changeTerminal, irreversible deteriorating change
Results in cell breakdown and deathResults in cell breakdown and death
Obvious period of physical declineObvious period of physical declineCan also occur in leaves, seeds, flowers, or fruitsCan also occur in leaves, seeds, flowers, or fruitsExhibited in different waysExhibited in different ways
Total plant deathTotal plant death Top plant deathTop plant death
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Usually a natural occurrence, but can be induced Usually a natural occurrence, but can be induced by disease or stressby disease or stress
Can be postponed by removing dead flowersCan be postponed by removing dead flowers
AbscissionAbscission Losing leaves or fruitLosing leaves or fruit Involves abscisic acidInvolves abscisic acid
FruitsFruits Maturation process of fruitMaturation process of fruit Should be picked at ripening to prevent senescenceShould be picked at ripening to prevent senescence
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Sexual ReproductionSexual Reproduction Requires formation of flowers in order to get Requires formation of flowers in order to get
pollination and fertilizationpollination and fertilization Flower InductionFlower Induction
Perfect flowers – both stamen & pistilPerfect flowers – both stamen & pistil
What do the parts of the flower do?What do the parts of the flower do?
Houses gametes, attract pollinatorsHouses gametes, attract pollinators
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Pollination & FertilizationPollination & FertilizationPollination – transfer of pollen from anther to Pollination – transfer of pollen from anther to stigmastigma
What is self-pollination?What is self-pollination? Ex. Soybean & tomatoEx. Soybean & tomato
What is cross pollination?What is cross pollination? Ex. Corn & pine treesEx. Corn & pine trees How can this occur?How can this occur?
Fertilization occurs when a small tube from the Fertilization occurs when a small tube from the pollen grain grows through an opening in the ovary pollen grain grows through an opening in the ovary ((micropylemicropyle))
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Results in:Results in:Formation of the zygote or seedFormation of the zygote or seedEndospermEndosperm
Fruit Development & MaturationFruit Development & MaturationOvary begins to develop into a fruit after Ovary begins to develop into a fruit after fertilizationfertilizationFruit aids in the dispersal of seedsFruit aids in the dispersal of seeds
What are some adaptations to fruits that aid in dispersal?What are some adaptations to fruits that aid in dispersal?
SeedsSeedsThree main parts of seeds:Three main parts of seeds:
Seed coatSeed coatProtects embryoProtects embryo
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Stored food supplyStored food supplyEndosperm or cotyledonsEndosperm or cotyledonsFeed the embryo until it can make its own foodFeed the embryo until it can make its own food
EmbryoEmbryoThe new plantThe new plantPlumulePlumule – young shoot – young shootHypocotylHypocotyl – stem – stemRadicleRadicle – root – root
DormancyDormancySeeds will not germinate during dormancySeeds will not germinate during dormancyAids in protection of the embryo through unfit Aids in protection of the embryo through unfit environmental conditionsenvironmental conditions
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Can force seeds out of dormancy if we manipulate Can force seeds out of dormancy if we manipulate the environment, or the seedthe environment, or the seed
Asexual ReproductionAsexual Reproduction Ensures an exact replicate of the parent plantEnsures an exact replicate of the parent plant Enables plants to reproduce even if they don’t Enables plants to reproduce even if they don’t
produce seeds (Banana)produce seeds (Banana) 8 common types of Asexual Reproduction8 common types of Asexual Reproduction
CuttingsCuttingsGraftingGraftingBuddingBudding
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
LayeringLayering
DivisionDivision
RhizomesRhizomes
StolonsStolons
Tillers/suckersTillers/suckers
Plant ImprovementPlant Improvement Deliberate attempt to change genetic Deliberate attempt to change genetic
architecture of a plantarchitecture of a plant
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Modern PracticesModern PracticesWhat is the most common criterion for selection?What is the most common criterion for selection?Tends to affect all other functions of the plantTends to affect all other functions of the plantWhat are some other genetic selections?What are some other genetic selections?Research has allowed farmers to produce more Research has allowed farmers to produce more food from the same amount of landfood from the same amount of land
Basic GeneticsBasic GeneticsOffspring tend to be very similar to the parent, but Offspring tend to be very similar to the parent, but might not be identicalmight not be identical
Ex. Soybeans will be almost identical, Apple trees may Ex. Soybeans will be almost identical, Apple trees may be very differentbe very different
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Related to the amount of genetic variationRelated to the amount of genetic variation
New variations can suddenly appear (New variations can suddenly appear (mutationmutation))
Geneticists use these methods to create Geneticists use these methods to create new/improved varietiesnew/improved varieties
Phenotype vs. GenotypePhenotype vs. Genotype
Homozygous vs. HeterozygousHomozygous vs. Heterozygous
Dominant vs. Recessive & Incomplete DominanceDominant vs. Recessive & Incomplete Dominance Self-pollinationSelf-pollination
Produces virtual clones of the parentProduces virtual clones of the parent
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Cross-pollinationCross-pollinationGametes originate from different plantsGametes originate from different plantsMore chance for genetic variationMore chance for genetic variationHow does this affect plant breeding and How does this affect plant breeding and propagation of new varieties?propagation of new varieties?
HybridsHybridsObtained by crossing two or more true-breeding Obtained by crossing two or more true-breeding parentsparentsCan produce true-breeding corn lines with Can produce true-breeding corn lines with continual self-pollinationcontinual self-pollination
helps provide uniform parents and seedstockhelps provide uniform parents and seedstock
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Hybrids tend to be more vigorous and productiveHybrids tend to be more vigorous and productive Produced from two inbred parent linesProduced from two inbred parent lines
Easy in cornEasy in cornHard in soybeans because they are self-pollinating – Hard in soybeans because they are self-pollinating – must force cross-pollinationmust force cross-pollination
Remove some reproductive parts of the flower to Remove some reproductive parts of the flower to ensure desired crossensure desired cross
Pollen collection and pollination must be done manuallyPollen collection and pollination must be done manually
MutationsMutationsSudden change in genetic expressionSudden change in genetic expressionMost are undesirableMost are undesirableCan produce a desirable changeCan produce a desirable change
Unit 6: Vegetative Growth and Unit 6: Vegetative Growth and Plant PropagationPlant Propagation
Sometimes tough to replicate to due gene Sometimes tough to replicate to due gene interactionsinteractions
Easier in asexually propagated plantsEasier in asexually propagated plants
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