Processes affected by CO2 1) Pathways that consume CO2 2) pathways that release CO2 3) transpiration & stomatal number

Processes affected by [Sugar] Photosynthesis Sugars Energy Biosynthesis Storage Structure Osmotic regulation Signaling molecules

Processes affected by [Sugar]

AtHXK1-Dependent Gene Expression WT vs. gin2 Sucrose metabolism Starch biosynthesis Respiration Photosynthesis Photorespiration Fatty acid synthesis & mobilization HXK1/GIN2 Flavonoid synthesis Cell wall synthesis Nitrogen metabolism Defense ROS scavenging / Detoxification Antioxidant protection Cytokinin signaling Auxin signaling Light signaling Ca2+ signaling Upregulated in gin2 Downregulated in gin2

Processes affected by [Sugar] Photosynthesis Sugar turns down light & dark rxns Affects partitioning inside cells 1 in 6 G3P becomes (CH2O)n either becomes starch in cp (to store in cell)

Processes affected by [Sugar] Photosynthesis Sugar turns down light & dark rxns Affects partitioning inside cells 1 in 6 G3P becomes (CH2O)n either becomes starch in cp (to store in cell) or is converted to DHAP & exported to cytoplasm to make sucrose

Processes affected by [Sugar] Photosynthesis Sugar turns down light & dark rxns Affects partitioning inside cells 1 in 6 G3P becomes (CH2O)n either becomes starch in cp (to store in cell) or is converted to DHAP & exported to cytoplasm to make sucrose Pi/triosePO4 antiporter only trades triosePO4 for Pi: mechanism to regulate PS

Processes affected by [Sugar] Photosynthesis Sugar turns down light & dark rxns Affects starch accumulation

Processes affected by [Sugar] Photosynthesis Sugar turns down light & dark rxns Affects starch accumulation

Processes affected by [Sugar] Photosynthesis Sugar turns down light & dark rxns Affects starch accumulation & degradation

Processes affected by [Sugar] Photosynthesis And sucrose transport

Processes affected by [Sugar] Photosynthesis And sucrose transport “Sink strength” determines where sucrose goes Rate depends on “phloem loading” by sucrose Transporters and other unidentified factors

Phloem Unloading Source cells control overall supply: decide allocation to sucrose vs starch But: are sensitive to sinks, PS goes up if sinks get stronger Sucrose represses PS genes

Phloem Unloading Source cells control overall supply: decide allocation to sucrose vs starch But: are sensitive to sinks, PS goes up if sinks get stronger Sucrose represses PS genes Rest of plant doesn’t need it

Processes affected by [Sugar] Photosynthesis Sugar turns down light & dark rxns Inhibits growth

Processes affected by [Sugar] Photosynthesis Sugar turns down light & dark rxns Inhibits growth Induces senescence

Plants and Temperature Affects enzymes

Plants and Temperature Affects enzymes: too slow if cold, denature if too hot

Plants and Temperature Affects enzymes: too slow if cold, denature if too hot Rubisco activase is very T sensitive; way to limit PR?

Plants and Temperature Affects enzymes Affects membranes fluidity

Plants and Temperature Affects enzymes Affects membranes Fluidity: must be correct Too stiff, may leak if too cold

Plants and Temperature Affects enzymes Affects membranes Fluidity: must be correct Too stiff, may leak if too cold Denature if too warm

Plants and Temperature Affects enzymes Affects membranes Fluidity: must be correct Too stiff, may leak if too cold Denature if too warm PSII denatures first! Lipids & proteins denature

Plants and Temperature PSII sets Topt & upper limit for C4 plants Topt for C3 also depends on photorespiration -> varies with pCO2

Plants and Temperature PSII sets Topt & upper limit for C4 plants Topt for C3 also depends on photorespiration -> varies with pCO2 Have respiration compensation point

Plants and Temperature PSII sets Topt & upper limit for C4 plants Topt for C3 also depends on photorespiration Limiting factor varies at lower T depending on which enzymes fall behind -> rubisco usually limits C3

Plants and Temperature Heat dissipation Long wave-length radiation Sensible heat loss Conduction & convection to cool air Evaporation

Transition to Flowering Can be affected by T FLC blocks flowering in fall; after 20 days near 0˚C plants make COLDAIR ncRNA FKF1 b

FLC blocks flowering in fall; after 20 days near 0˚C plants make COLDAIR ncRNA: Targets Polycomb Repressor Complex 2 to FLC locus & makes H3K27me3 -> silences gene

Transition to Flowering Can be affected by T FLC blocks flowering in fall; after 20 days near 0˚C plants make COLDAIR ncRNA ->PRC2 silences FLC Can then flower next spring

Transition to Flowering Can be affected by T FLC blocks flowering in fall; after 20 days near 0˚C plants make COLDAIR ncRNA ->PRC2 silences FLC Can then flower next spring PIF4 activates flowering @ high T by inducing FT mRNA (ind of daylength)

Transition to Flowering Can be affected by T PIF4 activates flowering @ high T by inducing FT mRNA (ind of daylength) Plants vary widely in how high T influences flowering

Growth regulators Auxins Cytokinins Gibberellins Abscisic acid Ethylene Brassinosteroids All are small organics: made in one part, affect another part

Growth regulators All are small organics: made in one part, affect another part Treating a plant tissue with a hormone is like putting a dime in a vending machine. It depends on the machine, not the dime!

Auxin First studied by Darwins! Showed that a "transmissible influence" made at tips caused bending lower down

Auxin First studied by Darwins! Showed that a "transmissible influence" made at tips caused bending lower down No tip, no curve!

Auxin First studied by Darwins! Showed that a "transmissible influence" made at tips caused bending lower down No tip, no curve! 1913:Boysen-Jensen showed that diffused through agar blocks but not through mica

Auxin 1913:Boysen-Jensen showed that diffused through agar blocks but not through mica 1919: Paal showed that if tip was replaced asymmetrically, plant grew asymmetrically even in dark

Auxin 1913:Boysen-Jensen showed that diffused through agar blocks but not through mica 1919: Paal showed that if tip was replaced asymmetrically, plant grew asymmetrically even in dark Uneven amounts of "transmissible influence" makes bend

Auxin 1919: Paal showed that if tip was replaced asymmetrically, plant grew asymmetrically even in dark Uneven amounts of "transmissible influence" makes bend 1926: Went showed that a chemical that diffused from tips into blocks caused growth

Auxin 1919: Paal showed that if tip was replaced asymmetrically, plant grew asymmetrically even in dark Uneven amounts of "transmissible influence" makes bend 1926: Went showed that a chemical that diffused from tips into blocks caused growth If placed asymmetrically get bending due to asymmetrical growth

Auxin 1919: Paal showed that if tip was replaced asymmetrically, plant grew asymmetrically even in dark Uneven amounts of "transmissible influence" makes bend 1926: Went showed that a chemical that diffused from tips into blocks caused growth If placed asymmetrically get bending due to asymmetrical growth Amount of bending depends on [auxin]

Auxin 1919: Paal showed that if tip was replaced asymmetrically, plant grew asymmetrically even in dark Uneven amounts of "transmissible influence" makes bend 1926: Went showed that a chemical that diffused from tips into blocks caused growth If placed asymmetrically get bending due to asymmetrical growth Amount of bending depends on [auxin] 1934: Indole-3-Acetic acid (IAA) from the urine of pregnant women was shown to cause bending