COURSE OVERVIEW1) Understanding how plants work.2) Understanding how plant biologists work.

• Method• Technology

Plan CWe will pick a problem in plant physiology and see where it takes us.1.Biofuels 2.Climate/CO2 change3.Stress responses/stress avoidance4.Plant products5.Improving food production6.Biotechnology7.Phytoremediation 8.Plant movements9.Plant signaling (including neurobiology)10.Something else?

Plan C

1.Pick a problem2.Pick some plants to study3.Design some experiments4.See where they lead us

Plan CGrading?

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 Plants3 Parts

1. Leaf2. Stem3. Root

Vegetative Plants3 tissue types

1. Dermal2. Ground3. 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 Developmentumbrella 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 Developmentumbrella term for many processes• Embryogenesis• Seed dormancy and germination• Seedling Morphogenesis• Transition to flowering, fruit and seed formation

Plant Developmentumbrella term for many processes• Embryogenesis• Seed dormancy and germination• Seedling Morphogenesis• Transition to flowering, fruit and seed formation Many responses to environment

Plant DevelopmentUmbrella term for many processesUnique features of plant development• Cell walls: cells can’t move: Must grow towards/away from signals

Plant DevelopmentUmbrella term for many processesUnique 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 diffusion2) surface/volume ratio

• surface area increases more slowly than volume• exchange occurs only at surface• eventually have insufficient exchange for survival

Plant Cells1) Cell walls

• Carbohydrate barriersurrounding cell

Plant Cells1) Cell walls

•Carbohydrate barriersurrounding cell•Protects & gives cell shape

Plant Cells1) Cell walls

• Carbohydrate barriersurrounding cell• Protects & gives cell shape• 1˚ wall made first

• mainly cellulose

Plant Cells1) Cell walls

• Carbohydrate barriersurrounding cell• Protects & gives cell shape• 1˚ wall made first

• mainly cellulose• Can stretch!

Plant Cells1) Cell walls

• Carbohydrate barriersurrounding cell• Protects & gives cell shape• 1˚ wall made first

• mainly cellulose• Can stretch!

• 2˚ wall made after growth stops

Plant Cells1) Cell walls

• Carbohydrate barriersurrounding cell• Protects & gives cell shape• 1˚ wall made first

• mainly cellulose• Can stretch!

• 2˚ wall made after growth stops

• Lignins make it tough

Plant Cells1) Cell walls

• Carbohydrate barriersurrounding 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 Cells1) 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 Cells1) 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 Organelles1) Endomembrane System2) Putative endosymbionts

Endomembrane systemCommon features

• derived from ER

Endomembrane systemCommon features• derived from ER• transport is in vesicles

Endomembrane systemCommon features• derived from ER• transport is in vesicles• proteins & lipids are glycosylated

Endomembrane systemOrganelles derived from the ER1) ER2) Golgi3) Vacuoles 4) PlasmaMembrane5) Nuclear Envelope6) Endosome7) Oleosomes

ERNetwork of membranes t/out cell2 types: SER & RER

SERtubules that lack ribosomesfns:1) Lipid syn2) Steroid syn3) drug detox4) storing Ca2+

5) Glycogen catabolism

RERFlattened membranes studded with ribosomes1˚ fn = protein synthesis -> ribosomes are making proteins

ERSER & RER make new membrane!

GOLGI COMPLEXFlattened stacks of membranes made from ER

GOLGI COMPLEXIndividual, flattened stacks of membranes made from ERFn: “post office”:collect ER products, process & deliver themAltered in each stack

GOLGI COMPLEXIndividual, flattened stacks of membranes made from ERFn: “post office”:collect ER products, process & deliver themAltered in each stackMakes most cell wall carbohydrates!

GOLGI COMPLEXIndividual, flattened stacks of membranes made from ERFn: “post office”:collect ER products, process & deliver themAltered in each stackMakes most cell wall carbohydrates!Protein’s address isbuilt in