Lecture16GrowthRegulatorsCytokinin

In vitro culture tobacco pith experiments skoog and

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Unformatted text preview: okinin-auxin ratio formation of roots • Roughly equal [cytokinin-auxin] formation of callus Plant Growth Substances - Cytokinin Cytokinin-Auxin Interactions it is very important that auxin and cytokinin interact with each other. • In vitro culture – Tobacco pith experiments • Skoog and Miller Auxin - Auxin + Cytokinin -Cytokinins + http://books.nap.edu/ Plant Growth Substances - Cytokinin Cytokinin-Auxin Interactions +Shoots Cytokinin - +transcription Auxin repressor protein Degradation of ARP + Cytokinin biosynthesis genes Auxin carrier genes Auxin +Roots they are antagonist toward each other cytokinin have a negative effect on auxin. + Plant Growth Substances - Auxin Physiological Effects • Promote lateral bud development Cytokinin biosynthesis Cytokinin oxidase + IAA IAA ******** - + Cyto Cytokinin biosynthesis – Cytokinin oxidase + - Cytokinin biosynthesis + Cytokinin oxidase - http://liveoakgardens.com/ Plant Growth Substances - Cytokinin auxin is produced in the apical dominant in shoot. so auxin supresses natural bud growth. if you cut off that apical meristem then there is no more auxin produced so there will be cytokinin oxidase…. it results in natural bud growth and eventually it will produce its own apical meristem where it would go back to normal. Cytokinin-Auxin Interactions • Agrobacterium tumefaciens – Ti (tumor inducing) plasmid • Crown gall disease • Formation of galls (tumors) • Auxin and cytokinin synthesis genes major way of creating transgenic plant. Plant Growth Substances - Cytokinin Cytokinin-Auxin Interactions • Agrobacterium tumefaciens – Ti (tumor inducing) plasmid • Formation of galls (tumors) • Auxin and cytokinin synthesis genes Plant Growth Substances - Cytokinin Drought effects on yields in WT and two lines of PSARK::IPT transgenic tobacco plants (PSARK::IPT2-36 and PSARK::IPT4-24). Root derived cytokinin blocks senescence Rivero R M et al. PNAS 2007;104:19631-19636 ©2007 by National Academy of Sciences Commercial Use of Cytokinin • Reduce yellowing of leaves • Postharvest applications +Cytokinin Control Plant Growth Substances - Cytokinin Cytokinin increases cell division-> larger apples in the apple industry there is massive use of cytokinin. bc it promotes cell division that will be big apple. why can u use on apple? putting apple you are just promoting cell division. Plant Growth Substances - Auxin Commercial Use of Cytokinin • Production “enhancers” – Seaweed extracts with “cytokinin-like” activity http://www.seaweed.ie/ Plant Growth Substances - Cytokinin...
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This document was uploaded on 01/17/2014.

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