GROWTH PROMOTERS AND INHIBITORS Plant growth regulator Regulates

GROWTH PROMOTERS AND INHIBITORS

Plant growth regulator Regulates cell division n Differentiation n Root and shoot growth n Flowering n Aging n Works as promoter or inhibitor n

SYNTHETIC REGULATORS ARE ENGINEERED BY MAN n CAN EITHER PROMOTE PROCESSES OR INHIBIT PLANT PROCESSES n APPLIED TO PLANTS TO CONTROL PLANT GROWTH n

NATURAL REGULATORS OCCUR NATURALLY IN PLANTS n ARE HORMONES n EITHER PROMOTE OR INHIBIT CELLS DIVISION, DIFFERENTIATION, ROOT AND SHOOT GROWTH, FLOWERING AND AGING n

HORMONES n CHEMICAL MESSINGERS THAT ARE PRODUCED BY PLANT TISSUE AND TRANSPORTED TO OTHER PARTS TO CONTROL GROWTH

AUXINS GROWTH PROMOTERS n PROMOTE GROWTH THROUGH CELL DIVISION AND ELONGATION n CONTROL PHOTOTROPISM, GEOTROPISM, APICAL DOMINANCE AND ROOT FORMATION in IBA AND NAA n

APICAL DOMINANCE TERMINAL BUD INFLUENCE ON PREVENTING DEVELOPMENT OF LOWER BUDS ON PLANT STEM n ALLOWS A PLANT TO BUSH OUT n GROWERS remove terminal bud to eliminate this in carnations, petunias and poinsettias n

GEOTROPISM CONTROLLED BY AUXINS n PLANTS RESPONSE TO GRAVITATIONAL FORCES – ROOTS GROW DOWN, STEMS GROW UP n

PHOTOTROPISM CONTROLLED BY AUXINS n CAUSES PLANTS TO GROW TOWARD LIGHT SOURCE n

IBA n n n ROOTING AUXIN APPLIED AS A DUST, DECREASES TIME NEEDED FOR ROOT DEVELOPMENT PRODUCES STRONG FIBROUS ROOT SYSTEM USUALLY MIXED WITH TALCUM POWDER THEN STEM CUTS ARE DIPPED IN IT Quick Dip Method – CUTTINGS DIPPED IN CONCENTRATED IBA FOR 5 -15 SECONDS THEN PUT IN ROOTING MEDIUM FOR 4 -8 WEEKS

NAA APPLIED AS DUST OR SOLUTION, ROOTING AUXIN n REDUCES TIME NEEDED FOR ROOT DEVELOPMENT n PRODUCES BUSHY STUNTED ROOT SYSTEMS n

GIBBERELLINS STEM GROWTH PROMOTER n PROMOTE CELL ELONGATION, CELL DIVISION AND CONTROL ENZYME RELEASE are over 70 of them n EX: APPLY TO A DWARF PLANT AND IT WILL GROW TO A NORMAL SIZE OR APPLY TO CELERY TO INCREASE STALK SIZE, used in grape industry to increase berry size n

CYTOTOXINS GROWTH PROMOTER n AFFECT CELL DIVISION, TISSUE DIFFERENTIATION, DORMANCY, LEAF AGING AND DROP n PRODUCED IN ROOT AND DEVELOPING SEEDS AND MOVE UP TOWARD SHOOTS n SLOW PLANT AGING called senescence n

ABSCISIC ACID ONLY NATURAL PLANT GROWTH INHIBITOR ALL REST ARE SYNTHETIC n PREVENTS SEEDS FROM GERMINATING WHILE IN THE FRUIT Why is that important? ? n MAINTAINS WATER SUPPLY IN PLANT TISSUE n

ETHYLENE WATER SOLUBLE GAS HORMONE n PRODUCED BY RIPENING FRUIT, OLD FLOWERS AND MERISTEMS, CAR EXHAUST AND SMOKE n ITS PRODUCTION BY ONE FRUIT CAUSES OTHERS IN CONTAINER TO RIPEN EX: ONE BAD APPLE SPOILS THE WHOLE BUSHEL n CAUSES FLOWERS TO DROP PETALS or DROOP AND “LOOK SLEEPY” n

FLOWER SHATTER DROP OF FLOWER PETALS( SHATTER) DUE TO ETHYLENE GAS PRESENT n REDUCED BY KEEPING PLANTS AWAY FROM RIPENING FRUITS AND VEGETABLES AND DECAYING OR WILTING PLANT TISSUE n

ANTIGIBBERELLINS COUNTERACT EFFECTS OF GIBBERELLINS - SYNTHETIC n REDUCE RATE OF GROWTH IN PLANTS n USED TO KEEP TREES AND SHRUBS SMALL OR FROM PRODUCING POLLEN n Remain active in tree for up to 4 years, usually injected in trunk n

n How is abscisic acid different from other naturally occurring plant regulators?

n Only natural plant growth inhibitor

n What plant growth processes will cytokinins control?

n Enlargement and division of cells, dormancy, leaf aging

n What hormones fall into plant inhibitors and which are plant growth promoters?

Promoters n Auxin n Geotrophism n Phototrophism n Gibberellin n Cytokinins n Ethylene n IBA, NAA n Inhibitors antigibberellins abscisic acid

n What are the 2 major groups of plant growth regulators?

Natural n synthetic n

n How many forms of gibberellins exist?

n Over 70

n What are the functions of plant growth regulators?

n Either to promote growth or inhibit it

n What might a combination of cytokinins and gibberellins do to an apple variety?

n Make a longer apple

n When would you want to use ethylene?

n To hasten ripening

n What does shatter refer to in plants? What business is especially concerned with it and why?

Petal drop n Florists n

n How are antigibberillons usually administered to trees and shrubs?

n Injected in trunk

n Phototrophism and geotrophism are controlled by what?

n Auxins

___ ___ ___ ___ A. B. C. D. E. F. G. H. I. J. K. L. M. N. O. formation 1. geotrophism 2. cytotoxins or cytokinins 3. apical dominance 4. abscisic acid 5. flower shatter 6. synthetic regulators 7. antigibberelins 8. hormones 9. natural growth regulators 10. gibberellins 11. auxins 12. phototrophism 13. IBA 14. NAA 15. ethylene rooting auxin, applied as dust, strong root system counteracts gibberlins - synthetic, reduce rate of growth drop of petals due to ehtylene gas terminal bud influence, prevents bud development of lower buds on stem works as promotor or inhibitor, are hormones only natural growth inhibitor controlled by auxins, roots grow down chemical messingers produced by ripening fruit, old flowers and car exhaust, causes flowers to droop stem growth promoters, for cell division, elongation over 70 growth promoters, slow plant aging, affect cell division, leaf drop rooting auxin, applied as dust reduces time for root development prodices bushy root systems are engineered by man controlled by auxins, lights grow toward the light growth promoters, for cell division and elongation, imp in phototrophism, geotrophism, apical dominance, root