Game plan We will study effects of elevated CO 2 and temperature on flowering time and see where it takes us. 1. Learn more about how plants choose when to flower

Game plan We will study effects of elevated CO 2 and temperature on flowering time and see where it takes us. 1. Learn more about how plants choose when to flower Environmental influences on flowering

Game plan We will study effects of elevated CO 2 and temperature on flowering time and see where it takes us. 1. Learn more about how plants choose when to flower Environmental influences on flowering 2. Pick some plants to study

Game plan We will study effects of elevated CO 2 and temperature on flowering time and see where it takes us. 1. Learn more about how plants choose when to flower Environmental influences on flowering 2. Pick some plants to study 3. Get them growing

Game plan We will study effects of elevated CO 2 and temperature on flowering time and see where it takes us. 1. Learn more about how plants choose when to flower Environmental influences on flowering 2. Pick some plants to study 3. Get them growing 4. Design some experiments for other things to test before they start flowering

Game plan Suggestions 1.Arabidopsis2. Fast plant 3. Sorghum4. Brachypodium distachyon 5. Amaranthus6. Quinoa 7. Kalanchoe8. Venus fly traps Options 1.Pick several plants

Game plan Suggestions 1.Arabidopsis2. Fast plant 3. Sorghum4. Brachypodium distachyon 5. Amaranthus6. Quinoa 7. Kalanchoe8. Venus fly traps Options 1.Pick several plants C3, C4, CAM

Game plan Suggestions 1.Arabidopsis2. Fast plant 3. Sorghum4. Brachypodium distachyon 5. Amaranthus6. Quinoa 7. Kalanchoe8. Venus fly traps Options 1.Pick several plants C3, C4, CAM Long Day, short day, Day neutral

Game plan Suggestions 1.Arabidopsis2. Fast plant 3. Sorghum4. Brachypodium distachyon 5. Amaranthus6. Quinoa 7. Kalanchoe8. Venus fly traps Options 1.Pick several plants C3, C4, CAM Long Day, short day, Day neutral Tropical, temperate, arctic

Game plan Suggestions 1.Arabidopsis2. Fast plant 3. Sorghum4. Brachypodium distachyon 5. Amaranthus6. Quinoa 7. Kalanchoe8. Venus fly traps Options 1.Pick several plants C3, C4, CAM Long Day, short day, Day neutral Tropical, temperate, arctic ?????

Game plan Suggestions 1.Arabidopsis2. Fast plant 3. Sorghum4. Brachypodium distachyon 5. Amaranthus6. Quinoa 7. Kalanchoe8. Venus fly traps Options 1.Pick several plants C3, C4, CAM Long Day, short day, Day neutral Tropical, temperate, arctic ????? 2.Pick one plant Study many conditions

Options 1.Pick several plants C3, C4, CAM Long Day, short day, Day neutral Tropical, temperate, arctic ????? 2.Pick one plant Study many conditions Study many variants/mutants ?????

Grading? Combination of papers, presentations & lab reports 4 lab 2.5 points each 5 2 points each Presentation on global change and plants: 5 points Research proposal: 10 points Final presentation: 15 points Poster: 10 points Draft report 10 points Final report: 30 points Assignment 1 1.Pick a plant that might be worth studying Try to convince the group in 5-10 minutes why yours is best: i.e., what is known/what isn’t known

Plant Growth & Development Occurs in 3 stages 1.Embryogenesis From fertilization to seed 2. Vegetative growth Juvenile stage From seed germination to adult "phase change" marks transition 3. Reproductive development Start making flowers, can reproduce sexually

Transition to Adult Phase Juveniles & adults are very different!

Transition to Flowering Adults are competent to flower, but need correct signals Very complex process! Can be affected by: Daylength Temperature (especially cold!) Water stress Nutrition Hormones

Early Studies Julius Sachs (1865) first proposed florigen Garner and Allard (1920) discovered photoperiodism Maryland Mammoth tobacco flowers in the S but not in N Knott (1934) day length is perceived by the leaves

Early Studies Knott (1934) day length is perceived by the leaves Flowers are formed at SAM! Florigen moves from leaves to SAM Is graft-transmissable! Moves in phloem

Complications Some plants are qualitative (must have correct daylength), others are quantitative (correct days speed flowering) Four pathways control flowering: 1.Photoperiod PHY only PHY + CRY 2.Vernalization: requires cold period 3.gibberellin (GA) 4.Autonomous

Complications Florigen is “universal”: transmitted from LDP to SDP and vice-versa via grafts Solved by identifying genes that control flowering time

Genes controlling flowering Florigen is “universal”: transmitted from LDP to SDP and vice-versa via grafts Solved by identifying genes that control flowering time 1.CONSTANS (CO): co mutants are day-length insensitive & flower late

Genes controlling flowering Florigen is “universal”: transmitted from LDP to SDP and vice-versa via grafts Solved by identifying genes that control flowering time 1.CONSTANS (CO): co mutants are day-length insensitive & flower late CO mRNA is expressed in leaf but not SAM & increases in LD

Genes controlling flowering Florigen is “universal”: transmitted from LDP to SDP and vice-versa via grafts Solved by identifying genes that control flowering time 1.CONSTANS (CO): co mutants are day-length insensitive & flower late CO mRNA is expressed in leaf but not SAM & increases in LD CO encodes a ZN-finger transcription factor (TF) that induces expression of FLOWERING LOCUS T (FT)

Genes controlling flowering Florigen is “universal”: transmitted from LDP to SDP and vice-versa via grafts Solved by identifying genes that control flowering time 1.CONSTANS (CO): co mutants are day-length insensitive & flower late CO mRNA is expressed in leaf but not SAM & increases in LD CO encodes a ZN-finger TF that induces expression of FLOWERING LOCUS T (FT) 2.FLOWERING LOCUS T (FT): a strong promoter of flowering

Genes controlling flowering Florigen is “universal”: transmitted from LDP to SDP and vice-versa via grafts Solved by identifying genes that control flowering time 1.CONSTANS (CO): co mutants are day-length insensitive & flower late CO mRNA is expressed in leaf but not SAM & increases in LD CO encodes a ZN-finger TF that induces expression of FLOWERING LOCUS T (FT) 2.FLOWERING LOCUS T (FT): a strong promoter of flowering: encodes a RAF kinase inhibitor protein

Genes controlling flowering 1.CONSTANS (CO): co mutants are day-length insensitive & flower late 2.FLOWERING LOCUS T (FT): a strong promoter of flowering: encodes a RAF kinase inhibitor protein 3. FLOWERING LOCUS C (FLC): a MADS-box gene strongly represses floweringMADS-box

Genes controlling flowering 1.CONSTANS (CO): co mutants are day-length insensitive & flower late 2.FLOWERING LOCUS T (FT): a strong promoter of flowering: encodes a RAF kinase inhibitor protein 3. FLOWERING LOCUS C (FLC): a MADS-box gene strongly represses floweringMADS-box Highly expressed in non-vernalized tissues

Genes controlling flowering 1.CONSTANS (CO): co mutants are day-length insensitive & flower late 2.FLOWERING LOCUS T (FT): a strong promoter of flowering: encodes a RAF kinase inhibitor protein 3. FLOWERING LOCUS C (FLC): a MADS-box gene strongly represses floweringMADS-box Highly expressed in non-vernalized tissues Turned off by vernalization due to chromatin mod

Genes controlling flowering 1.CONSTANS (CO): co mutants are day-length insensitive & flower late 2.FLOWERING LOCUS T (FT): a strong promoter of flowering: encodes a RAF kinase inhibitor protein 3. FLOWERING LOCUS C (FLC): a MADS-box gene strongly represses floweringMADS-box Highly expressed in non-vernalized tissues Turned off by vernalization due to chromatin mod 4.SUPPRESSOR OF CONSTANS 1 (SOC1): a MADS- BOX TF that activates genes for floral development.

Transition to flowering Upon induction, CO activates transcription of FT in leaves FT protein moves from leaves to shoot apex in phloem!

Transition to flowering Upon induction, CO activates transcription of FT in leaves FT protein moves from leaves to shoot apex in phloem! In SAM combines with FD to activate SOC1 & AP1

Transition to flowering Upon induction, CO activates transcription of FT FT protein moves from leaves to shoot apex in phloem! In SAM combines with FD to activate SOC1 &AP1 These activate LFY & Flower genes

Transition to flowering Upon induction, CO activates transcription of FT FT protein moves from leaves to shoot apex in phloem! In SAM combines with FD to activate SOC1 &AP1 These activate LFY & Flower genes Other signals converge On SOC1, either Directly or via FLC

SDP Rice homolog to CO is Hd1 Inhibits expression of Hd3a (the FT homolog)

SDP Rice homolog to CO is Hd1 Inhibits expression of Hd3a (the FT homolog) Induced by long days

SDP Rice homolog to CO is Hd1 Inhibits expression of Hd3a (the FT homolog) Induced by long days Only make Hd3a protein under short days

Transition to flowering Eventually start flowering Are now adults! Time needed varies from days to years. Shoot apical meristem now starts making new organ: flowers, with many new structures & cell types

WATER Plants' most important chemical most often limits productivity

WATER Plants' most important chemical most often limits productivity Often >90% of a plant cell’s weight

WATER Plants' most important chemical most often limits productivity Often >90% of a plant cell’s weight Gives cells shape

WATER Plants' most important chemical most often limits productivity Often >90% of a plant cell’s weight Gives cells shape Dissolves many chem

WATER Dissolves many chem most biochem occurs in water Source of e - for PS

WATER most biochem occurs in water Source of e - for PS Constantly lose water due to PS (1000 H 2 O/CO 2 )

WATER most biochem occurs in water Source of e - for PS Constantly lose water due to PS Water transport is crucial!

WATER Water transport is crucial! SPAC= Soil Plant Air Continuum moves from soil->plant->air

WATER Formula = H 2 O Formula weight = 18 daltons Structure = tetrahedron, bond angle 104.5˚

WATER Structure = tetrahedron, bond angle 104.5˚ polar :O is more attractive to electrons than H  + on H  - on O

Water Polarity is reason for water’s properties water forms H-bonds with polar molecules

Water Polarity is reason for water’s properties water forms H-bonds with polar molecules Hydrophilic = polar molecules Hydrophobic = non-polar molecules

Properties of water 1)Cohesion = water H-bonded to water -> reason for surface tension

Properties of water 1)Cohesion = water H-bonded to water -> reason for surface tension -> why water can be drawn from roots to leaves

Properties of water 1) Cohesion = water H-bonded to water 2) Adhesion = water H-bonded to something else

Properties of water 1) Cohesion = water H-bonded to water 2) Adhesion = water H-bonded to something else Cohesion and adhesion are crucial for water movement in plants!

Properties of water 1) Cohesion = water H-bonded to water 2) Adhesion = water H-bonded to something else Cohesion and adhesion are crucial for water movement in plants! Surface tension & adhesion in mesophyll creates force that draws water through the plant!

Properties of water 1) Cohesion = water H-bonded to water 2) Adhesion = water H-bonded to something else 3) high specific heat absorb heat when break H-bonds: cools leaves

Properties of water 1) Cohesion = water H-bonded to water 2) Adhesion = water H-bonded to something else 3) high specific heat absorb heat when break H-bonds Release heat when form H-bonds

Properties of water 1) Cohesion = water H-bonded to water 2) Adhesion = water H-bonded to something else 3) high specific heat 4) Ice floats

Properties of water 1) Cohesion = water H-bonded to water 2) Adhesion = water H-bonded to something else 3) high specific heat 4) Ice floats 5) Universal solvent

Properties of water 1) Cohesion = water H-bonded to water 2) Adhesion = water H-bonded to something else 3) high specific heat 4) Ice floats 5) Universal solvent Take up & transport nutrients dissolved in water

Properties of water 5) “Universal” solvent Take up & transport nutrients dissolved in water Transport organics dissolved in water

Properties of water 1) Cohesion = water H-bonded to water 2) Adhesion = water H-bonded to something else 3) high specific heat 4) Ice floats 5) Universal solvent 6) Hydrophobic bonds

Properties of water 1) Cohesion = water H-bonded to water 2) Adhesion = water H-bonded to something else 3) high specific heat 4) Ice floats 5) Universal solvent 6) Hydrophobic bonds 7) Water ionizes

pH [H + ] = acidity of a solution pH = convenient way to measure acidity pH = - log 10 [H + ] pH 7 is neutral: [H+] = [OH-] -> at pH 7 [H+] = moles/l

pH Plants vary pH to control many processes!

Water movement Diffusion: movement of single molecules down ∆[ ] due to random motion until [ ] is even Driving force?

Water movement Diffusion: movement of single molecules down ∆[ ] due to random motion until [ ] is even Driving force: lowers free energy ∆G = ∆H- T∆S

Water movement Diffusion: movement of single molecules down ∆[ ] due to random motion until [ ] is even Bulk Flow: movement of groups of molecules down a pressure gradient

Water movement Diffusion: movement of single molecules down ∆[ ] due to random motion until [ ] is even Bulk Flow: movement of groups of molecules down a pressure gradient Independent of ∆ [ ] !

Water movement Diffusion: movement of single molecules down ∆[] due to random motion until [ ] is even Bulk Flow: movement of groups of molecules down a pressure gradient Independent of ∆[ ] ! How water moves through xylem

Water movement Diffusion: movement of single molecules down [] due to random motion until [ ] is even Bulk Flow: movement of groups of molecules down a pressure gradient Independent of ∆ [ ] ! How water moves through xylem How water moves through soil and apoplast

Water movement Bulk Flow: movement of groups of molecules down a pressure gradient Independent of ∆ [ ] ! How water moves through xylem Main way water moves through soil and apoplast Very sensitive to radius of vessel: increases as r 4

Water movement Diffusion: movement of single molecules down ∆[] due to random motion until [ ] is even Bulk Flow: movement of groups of molecules down a pressure gradient Independent of ∆[ ] ! How water moves through xylem Main way water moves through soil and apoplast Very sensitive to radius of vessel: increases as r 4 Osmosis: depends on bulk flow and diffusion!

Water movement Osmosis: depends on bulk flow and diffusion! water crosses membranes but other solutes do not water tries to even its [ ] on each side

Water movement Osmosis: depends on bulk flow and diffusion! water crosses membranes but other solutes do not water tries to even its [ ] on each side other solutes can’t: result is net influx of water

Water movement Osmosis: depends on bulk flow and diffusion! Moves through aquaporins, so rate depends on pressure and [ ] gradients!

Water movement Osmosis: depends on bulk flow and diffusion! Moves through aquaporins, so rate depends on pressure and [ ] gradients! Driving force = water's free energy (J/m 3 = MPa)

Water potential Driving force = water's free energy = water potential  w Important for many aspects of plant physiology

Water potential Driving force = water's free energy = water potential  w Water moves to lower its potential

Water potential Driving force = water's free energy = water potential  w Water moves to lower its potential

Water potential Driving force = water's free energy = water potential  w Water moves to lower its potential Depends on: 1.[H 2 O]:  s (osmotic potential)

Water potential Water moves to lower its potential Depends on: 1.[H 2 O]:  s (osmotic potential) 2.Pressure :  p Turgor pressure inside cells

Water potential Water moves to lower its potential Depends on: 1.[H 2 O]:  s (osmotic potential) 2.Pressure :  p Turgor pressure inside cells Negative pressure in xylem!

Water potential Water moves to lower its potential Depends on: 1.[H 2 O]:  s (osmotic potential) 2.Pressure  p 3.Gravity  g  w =  s +  p +  g

Water potential Water moves to lower its potential Depends on: 1.[H 2 O]:  s (osmotic potential) 2.Pressure  p 3.Gravity  g  w =  s +  p +  g  w of pure water at sea level & 1 atm = 0 MPA

Water potential  w =  s +  p +  g  w of pure water at sea level & 1 atm = 0 MPA  s (osmotic potential) is always negative

Water potential  w =  s +  p +  g  w of pure water at sea level & 1 atm = 0 MPA  s (osmotic potential) is always negative If increase [solutes] water will move in

Water potential  w =  s +  p +  g  w of pure water at sea level & 1 atm = 0 MPA  s (osmotic potential) is always negative If increase [solutes] water will move in  p (pressure potential) can be positive or negative

Water potential  w =  s +  p +  g  w of pure water at sea level & 1 atm = 0 MPA  s (osmotic potential) is always negative If increase [solutes] water will move in  p (pressure potential) can be positive or negative Usually positive in cells to counteract  s

Water potential  p (pressure potential) can be positive or negative Usually positive in cells to counteract  s Helps plants stay same size despite daily fluctuations in  w

Water potential  w =  s +  p +  g  p (pressure potential) can be positive or negative Usually positive in cells to counteract  s Helps plants stay same size despite daily fluctuations in  w  p in xylem is negative, draws water upwards

Water potential  w =  s +  p +  g  p (pressure potential) can be positive or negative Usually positive in cells to counteract  s Helps plants stay same size despite daily fluctuations in  w  p in xylem is negative, draws water upwards  g can usually be ignored, but important for tall trees