Lecture16GrowthRegulatorsCytokinin

These are all that result to positive growth when

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Unformatted text preview: m DNA) it tells us something interesting is that there is something in the root. these are all that result to positive growth. when added these somehow they grew Plant Growth Substances - Cytokinins Plant Growth Substances • Cytokinin – Chemical types and structure – Biosynthesis – Transport – Mode of action – Detection – Physiological effects – Cytokinin:Auxin interactions – Commercial use good explanation for cytokinin Good basic explanation: http://plantphys.info/plant_ph ysiology/cytokinin.shtml Plant Growth Substances - Cytokinin Cytokinin • All derivatives of the purine adenine • Natural that is why adding adenine it resulted in stimulation bc it is the building block of cytokinin – Zeatin • First found in Zea mays (maize) • Found in coconut water – Isopentenyl adenine natural cytokinin Plant Growth Substances - Cytokinin http://www.nandyala.org/mahanandi/ Cytokinin these are synthetic cytokinin. • Synthetic – Kinetin (degradation product of DNA) the Sperm DNA works bc of this. • 6-furfurylaminopurine – BAP • Benzyladenine or benzylaminopurine – Thidiazuron • 1-phenyl-3-(1,2,3thiadiazol-5-yl)urea Plant Growth Substances - Cytokinin Biosynthesis this is where cytokinin is produced/ • Root tips – Major site of biosynthesis • Young organs • Immature seeds http://botit.botany.wisc.edu/ http://www.inhs.uiuc.edu/~kenr/ http://www.trulyfreestock.com/ Plant Growth Substances - Cytokinin water goes through the endodermis bc there is alot of salt. root pressure can cause water to come out the stem. Transport Text it flows in the xylem everywhere it goes from the root meristem. • Predominately in the xylem – Supported by decapitation experiments • Decapitate Citrus seedlings • Collect xylem sap • Chemically identify and quantify cytokinins – Also present in sieve tubes Plant Growth Substances - Cytokinin Mode of Action • Regulate protein synthesis – Suggested by experiments where RNA and protein synthesis inhibitors blocked cytokinin action • A transmembrane protein binds to external cytokinin • In the cytoplasm this leads to phosphate transfer chain to the nucleus -> transcription regulation Plant Growth Substances - Cytokinin Metabolism • Maintenance of steady-state condition – Conversion to inactive compounds • Cytok...
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This document was uploaded on 01/17/2014.

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