Lecture_12

Lecture_12 - Review of seedling growth controls Etiolated...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Review of seedling growth controls • Etiolated growth (regulation by light, brassinosteroids) • Phototropism (regulation by light, auxin: transport and effects on growth) • Organ initiation (regulation by auxin) Recurring themes: • Multiple receptors for given hormone • Cross-talk between hormones: converging and antagonistic effects • Signaling involves interactions between activators and repressors (reflected genetically in resistant and constitutive response mutants), often conserved protein classes • Induction of response often requires derepression D L D L D L Wild-type “blind” ( hy ) de-etiolated Genetic approach to auxin response Auxin promotes: •Embryonic pattern formation •Root meristem formation and growth •Vascular differentiation •Lateral organ initiation •Cell elongation •Apical dominance axr rol axr Plant morphology reflects auxin/cytokinin antagonism Plant cells are totipotent: Given “right” combination of growth regulators, nearly all live plant cells can regenerate an entire plant What are the “right” regulators?
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 How do you identify the “right” regulators to promote growth? Try everything you can think of, alone and in different combinations! Plant organogenesis is controlled by auxin/cytokinin balance -auxins produced in shoots -cytokinins produced in roots -ratio reflects balance of source tissues Cytokinins are the plant’s “fountain of youth” •Aging plant organs senesce •Senescence is degradation of macromolecules and exporting nutrients to rest of plant before falling off •Cytokinins inhibit senescence; antagonized by ethylene and ABA Cytokinin perception and signaling Cytokinin receptors are also members of 2-component receptor superfamily Signaling involves a kinase cascade
Background image of page 2
3 Summary of key concepts about cytokinin signaling •Cytokinins were discovered as growth-promoting
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/07/2008 for the course MCDB 1B taught by Professor Weimbs during the Winter '08 term at UCSB.

Page1 / 7

Lecture_12 - Review of seedling growth controls Etiolated...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online