1. The bright side of life: Photomorphogenesis

2. Cells and cell growth Membranes and cell walls Fertilization and embryogenesis Seed development and dormancy Germination Water transport Water relations Plant nutrition Solute transport Gene function Skotomorphogenesis Photomorphogenesis

3. Three learning goals : - what is a photomorphogenesis plant development with light requirements: light regulated development transcription factors that respond to light signals - photoreceptors and their integration in development how plants “see” light and what happens then requirements: photoreceptor molecules that are sensitive at appropriate wavelengths - photomorphogenesis during seedling development requirements: signal transduction apparatus that connects light responses and seedling development

4. What is not regulated by light ???

5. SKOTOMORPHOGENESIS Photomorphogenesis Skotomorphogenesis

6. Sunflower seedling development in dark and light

7. SKOTOMORPHOGENESIS Skotomorphogenesis Light has an influence on seedling development Skotomorphogenesis Photomorphogenesis  Hypocotyl: long short  Apical hook: closed open  Cotyledons: closed expanded  Chloroplasts: proplastids fully developed  Photosynthesis: no yes

8. Cotyledon expansion Reduced hypocotyl elongation Open apical hook

9. closed apical hook Non-expanded cotyledons Etiolated hypocotyl Is skotomorphogenesis achived via active repression of photomorphogenesis

10. How to perform genetic approaches to decifer light regulation in plants ???

11. How to perform genetic approaches to decifer light regulation in plants ??? Photomorphogenesis in dark grown seedlings Skotomorphogenesis in light grown seedlings Asking simple questions

12. Getting complicated answers !! Short hypocotyl Expanded cotyledons Open apical hook

13. Skotomorphogenesis in the light

14. Dark Light wild-type cop/det mutants COP and DET proteins inhibit photomorphogenesis

17. Regulation of skotomorphogenesis by GA

19. Germination in dark and light

21. Gene activation through photoreceptors and PIF proteins Hemara

22. Photomorphogenesis via protein regulation (protein stability and turnover) day night