Transcript Jan 14
COURSE OVERVIEW 1) Understanding how plants work. 2) Understanding how plant biologists work. • Method • Technology Plan C We will pick a problem in plant physiology and see where it takes us. 1.Biofuels 2.Climate/CO2 change 3.Stress responses/stress avoidance 4.Plant products 5.Improving food production 6.Biotechnology 7.Phytoremediation 8.Plant movements 9.Plant signaling (including neurobiology) 10.Something else? Plan C 1.Pick a problem 2.Pick some plants to study 3.Design some experiments 4.See where they lead us Plan C Grading? Combination of papers and presentations •First presentation:10 points •Research presentation: 10 points •Final presentation: 15 points •Assignments: 5 points each •Poster: 10 points •Intermediate report 10 points •Final report: 30 points •Scavenger hunts? Vegetative Plants 3 Parts 1. Leaf 2. Stem 3. Root Vegetative Plants 3 tissue types 1. Dermal 2. Ground 3. Vascular • Plant Development Cell division = growth • • Plant Development Cell division = growth Determination = what cell can become • • • Plant Development Cell division = growth Determination = what cell can become Differentiation = cells become specific types • • • • Plant Development Cell division = growth Determination = what cell can become Differentiation = cells become specific types Pattern formation: developing specific structures in specific locations • • • • • Plant Development Cell division = growth Determination = what cell can become Differentiation = cells become specific types Pattern formation Morphogenesis: organization into tissues & organs Plant Development umbrella term for many processes • embryogenesis Plant Development umbrella term for many processes • Embryogenesis • Seed dormancy and germination Plant Development umbrella term for many processes • Embryogenesis • Seed dormancy and germination • Seedling Morphogenesis Plant Development umbrella term for many processes • Embryogenesis • Seed dormancy and germination • Seedling Morphogenesis • Transition to flowering, fruit and seed formation Plant Development umbrella term for many processes • Embryogenesis • Seed dormancy and germination • Seedling Morphogenesis • Transition to flowering, fruit and seed formation Many responses to environment Plant Development Umbrella term for many processes Unique features of plant development • Cell walls: cells can’t move: Must grow towards/away from signals Plant Development Umbrella term for many processes Unique features of plant development • Cell walls: cells can’t move: must grow instead • Plasticity: plants develop in response to environment Unique features of plant development • Cell walls: cells can’t move • Plasticity: plants develop in response to environment • Totipotency: most plant cells can form an entire new plant given the correct signals • • • • Unique features of plant development Cell walls: cells can’t move Plasticity: plants develop in response to environment Totipotency: most plant cells can form an entire new plant given the correct signals Meristems: plants have perpetually embryonic regions, and can form new ones • • • • Unique features of plant development Cell walls: cells can’t move Plasticity: plants develop in response to environment Totipotency: most plant cells can form an entire new plant given the correct signals Meristems: plants have perpetually embryonic regions, and can form new ones • No germ line! Unique features of plant development • Meristems: plants have perpetually embryonic regions, and can form new ones • No germ line! Cells at apical meristem become flowers: allows Lamarckian evolution! Unique features of plant development • Meristems: plants have perpetually embryonic regions, and can form new ones • No germ line! Cells at apical meristem become flowers: allows Lamarckian evolution! • Different parts of the same 2000 year old tree have different DNA & form different gametes Why are cells so small? 1) many things move inside cells by diffusion 2) surface/volume ratio • surface area increases more slowly than volume • exchange occurs only at surface • eventually have insufficient exchange for survival Plant Cells 1) Cell walls • Carbohydrate barrier surrounding cell Plant Cells 1) Cell walls • Carbohydrate barrier surrounding cell • Protects & gives cell shape Plant Cells 1) Cell walls • Carbohydrate barrier surrounding cell • Protects & gives cell shape • 1˚ wall made first • mainly cellulose Plant Cells 1) Cell walls • Carbohydrate barrier surrounding cell • Protects & gives cell shape • 1˚ wall made first • mainly cellulose • Can stretch! Plant Cells 1) Cell walls • Carbohydrate barrier surrounding cell • Protects & gives cell shape • 1˚ wall made first • mainly cellulose • Can stretch! • 2˚ wall made after growth stops Plant Cells 1) Cell walls • Carbohydrate barrier surrounding cell • Protects & gives cell shape • 1˚ wall made first • mainly cellulose • Can stretch! • 2˚ wall made after growth stops • Lignins make it tough Plant Cells 1) Cell walls • Carbohydrate barrier surrounding cell • Protects & gives cell shape • 1˚ wall made first • mainly cellulose • Can stretch! • 2˚ wall made after growth stops • Lignins make it tough • Problem for "cellulosic Ethanol" from whole plants Plant Cells 1) Cell walls • 1˚ wall made first • 2˚ wall made after growth stops • Lignins make it tough • Problem for "cellulosic Ethanol" from whole plants • Middle lamella = space between 2 cells Plant Cells 1) Cell walls • 1˚ wall made first • 2˚ wall made after growth stops • Middle lamella = space between 2 cells • Plasmodesmata = gaps in walls that link cells • Plant Cells Plasmodesmata = gaps in walls that link cells • Lined with plasma membrane • Plant Cells Plasmodesmata = gaps in walls that link cells • Lined with plasma membrane • Desmotubule joins ER of both cells • Plant Cells Plasmodesmata = gaps in walls that link cells • Lined with plasma membrane • Desmotubule joins ER of both cells • Exclude objects > 1000 Dalton, yet viruses move through them! Types of Organelles 1) Endomembrane System 2) Putative endosymbionts Endomembrane system Common features • derived from ER Endomembrane system Common features • derived from ER • transport is in vesicles Endomembrane system Common features • derived from ER • transport is in vesicles • proteins & lipids are glycosylated Endomembrane system Organelles derived from the ER 1) ER 2) Golgi 3) Vacuoles 4) Plasma Membrane 5) Nuclear Envelope 6) Endosome 7) Oleosomes ER Network of membranes t/out cell 2 types: SER & RER SER tubules that lack ribosomes fns: 1) Lipid syn 2) Steroid syn 3) drug detox 4) storing Ca2+ 5) Glycogen catabolism RER Flattened membranes studded with ribosomes 1˚ fn = protein synthesis -> ribosomes are making proteins ER SER & RER make new membrane! GOLGI COMPLEX Flattened stacks of membranes made from ER GOLGI COMPLEX Individual, flattened stacks of membranes made from ER Fn: “post office”: collect ER products, process & deliver them Altered in each stack GOLGI COMPLEX Individual, flattened stacks of membranes made from ER Fn: “post office”: collect ER products, process & deliver them Altered in each stack Makes most cell wall carbohydrates! GOLGI COMPLEX Individual, flattened stacks of membranes made from ER Fn: “post office”: collect ER products, process & deliver them Altered in each stack Makes most cell wall carbohydrates! Protein’s address is built in