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Plant Growth Regulators
Plant Growth Regulators
Plant Growth Regulators
are naturally occurring or synthetic compounds that affect plant growth
and development
Plant Growth Regulators
are naturally occurring or synthetic compounds that affect plant growth
and development
3 Types of Chemical Plant Growth Regulators
3 Types of Chemical Plant Growth Regulators
Growth-inhibiting Growth-inhibiting chemicalschemicals
Growth-promoting Growth-promoting chemicalschemicals
Root-promoting chemicalsRoot-promoting chemicals
Plant Hormones“Chemical Messengers”
Plant Hormones“Chemical Messengers”
AuxinsAuxins Cytokinins Cytokinins GibberellinsGibberellins EthyleneEthylene
Rooting HormonesRooting Hormones
Auxin, which stimulates rooting, is Auxin, which stimulates rooting, is the main component the main component
IAA (indoleacetic acid) IAA (indoleacetic acid) IBA (indolebutyric acid) IBA (indolebutyric acid) NAA (naphthaleneacetic acid)NAA (naphthaleneacetic acid)
Rooting HormonesRooting Hormones
Combination of IBA and NAACombination of IBA and NAA Powder FormulationsPowder Formulations
HormodinHormodin Hormo-RootHormo-Root Rhizopon AARhizopon AA
Liquid FormulationsLiquid Formulations Woods Rooting CompoundWoods Rooting Compound Dip’ N GrowDip’ N Grow
Liquid HormonesLiquid Hormones
Powder HormonesPowder Hormones
CytokininsCytokinins
Responsible for shoot initiationResponsible for shoot initiation Present in rapidly dividing tissuePresent in rapidly dividing tissue Benzyladenine (BA) Benzyladenine (BA)
synthetic cytokininsynthetic cytokinin increases offset formation in hostaincreases offset formation in hosta
Gibberellic Acid (GA)Gibberellic Acid (GA)
Promotes cellular elongation Promotes cellular elongation (stretched internodes)(stretched internodes)
Increases fruit setIncreases fruit set Pro-GibbPro-Gibb: Enlarges flowers and : Enlarges flowers and
elongates peduncles (stems elongates peduncles (stems supporting flowers)supporting flowers)
Ethylene GasEthylene Gas
Affects cell division and Affects cell division and developmentdevelopment
Cause floweringCause flowering Causes fruit ripeningCauses fruit ripening Causes leaf abscissionCauses leaf abscission
Plant Growth Retardants (PGRs)
are any chemicals that slow cell division and elongation in shoot
tissues
Plant Growth Retardants (PGRs)
are any chemicals that slow cell division and elongation in shoot
tissues
Why Control Growth?Why Control Growth?
Blow-overBlow-over Plants out-grow potsPlants out-grow pots Watering becomes difficultWatering becomes difficult Increased shipping costsIncreased shipping costs Leggy, low quality plantsLeggy, low quality plants
Methods of Growth ControlMethods of Growth Control
PruningPruning costly and time consumingcostly and time consuming
GeneticsGenetics not always availablenot always available consumers wary of GMOsconsumers wary of GMOs
Methods of Growth ControlMethods of Growth Control
Environmental controlsEnvironmental controlsLow fertilityLow fertilityNegative DIF (Temp)Negative DIF (Temp)Water StressWater StressBrushing, vibrations, and other Brushing, vibrations, and other
mechanical disturbancesmechanical disturbances
Many growers find chemical plant growth
retardants to be an effective and inexpensive method of growth control
Many growers find chemical plant growth
retardants to be an effective and inexpensive method of growth control
How do they work?How do they work?
Gibberellin Gibberellin Biosynthesis InhibitorsBiosynthesis Inhibitors
Release of Ethylene Release of Ethylene
Notice branching effectsNotice branching effects
Notice height controlNotice height control
Synergistic effects of two PGRsSynergistic effects of two PGRs
Increasing PGR Effectiveness In Non-responsive Perennials
Additional Benefits:Additional Benefits:
Control production scheduleControl production schedule Increase branchingIncrease branching Induce floweringInduce flowering Drought tolerantDrought tolerant Pollution tolerantPollution tolerant
Additional Benefits:Additional Benefits:
Intensely green foliageIntensely green foliage Resistant to mechanical Resistant to mechanical
damagedamage Protection from some pests Protection from some pests
(whiteflies)(whiteflies) Overall higher quality and Overall higher quality and
aesthetic valueaesthetic value
PGRs for use in Greenhouses:PGRs for use in Greenhouses: B-NineB-Nine
CycocelCycocel BonziBonzi
SumagicSumagic FlorelFlorel A-RestA-Rest
Chemical PGRsChemical PGRs
B-Nine (Daminozide)B-Nine (Daminozide) labeled for annuals and labeled for annuals and
herbaceous perennialsherbaceous perennials low activity (relatively safe)low activity (relatively safe)
Cycocel (Chlormequatchloride)Cycocel (Chlormequatchloride)not labeled on many cropsnot labeled on many cropscauses yellowing above 1500 causes yellowing above 1500
ppmppm
Chemical PGRsChemical PGRs
B-Nine/Cycocel tank mixesB-Nine/Cycocel tank mixesSynergistic combinationSynergistic combinationCycocel 800-1,500 ppmCycocel 800-1,500 ppmB-Nine 800-5,000 ppmB-Nine 800-5,000 ppm
Chemical PGRsChemical PGRs
A-Rest (Ancymidol)A-Rest (Ancymidol)intermediate activityintermediate activitybroad labelbroad label
Chemical PGRsChemical PGRs
Bonzi (Paclobutrazol)Bonzi (Paclobutrazol) broad spectrum labelbroad spectrum label high activityhigh activity
Sumagic (Uniconazole)Sumagic (Uniconazole) broad spectrum labelbroad spectrum label most active PGRmost active PGR
Chemical PGRsChemical PGRs
Florel, Ethrel, Pistill, (Ethephon)Florel, Ethrel, Pistill, (Ethephon)causes plant to release ethylenecauses plant to release ethylenenarrow-spectrum labelnarrow-spectrum label
PGR EfficacyPGR Efficacy
Application timingApplication timingDosageDosageTarget tissueTarget tissue
foliage/stemsfoliage/stemssubstratesubstrate
PGR EfficacyPGR Efficacy
Environmental ConditionsEnvironmental Conditionsenvironment at applicationenvironment at applicationstatus of plantstatus of plantpost-application treatmentpost-application treatment
Application TechniqueApplication Technique
ApplicationApplication
Chemical must be accurately Chemical must be accurately measuredmeasured
ALWAYS wear long sleeves, ALWAYS wear long sleeves, pants, gloves, and shoes with pants, gloves, and shoes with closed toes when mixing and closed toes when mixing and applying PGRs!!!!!!applying PGRs!!!!!!
Media DrenchesMedia Drenchesspecific specific
volume/potvolume/pot
Foliar Sprays Foliar Sprays Specific Specific
volume/area volume/area (0.5gallons/ (0.5gallons/ 100ft100ft22))
PGR overdosePGR overdose Example: Bonzi overdose on Example: Bonzi overdose on
pansiespansies Ways To ReverseWays To Reverse
gibberellins (Pro-Gibb) gibberellins (Pro-Gibb) high-N nutritionhigh-N nutrition
QUESTIONS? QUESTIONS?