Factors that affect Photosynthesis

Factors that affect Photosynthesis

1. Light- Quantity or quality

2. Temp- to hot or to cold

3. CO2- often limits C3 plants

4. Minerals- especially NPK and Mg

5. Water availability

Importance

1. Food- either directly or indirectly comes from plants

2. oxygen in air

3. carbon balance

4. plant products

5. life on earth

Photo respiration

• when C3 plants take in O2 instead of CO2 into the Calvin cycle

• rubisco “mistakes" O2 for CO2

• result: photosynthesis output is reduced by 50%

C3

• occurs in: 85% of all plants

• Location of CC: Mesophyll cells

• Note: Can photorespirate in hot, dry conditions

C4

• occurs: corn sugarcane

• Location CC- location change: bundle shell sheets

• Note- avoid photorespiration by first capturing CO2 in mesophyll cells + converting it into a C4 compound that is than transferred into the bundle sheets

CAM

located: cacti, orchids, and succulents

Location of CC: Mesophyll Cells

Note: Plants use stomata during day and then capture CO2 at night

• CO2 is stored as a 4C acid overnight

• during the day its converted back into CO2- Calvin cycle