Factors the Affect Photosynthesis

1. Light Quality (color)
2. Light intensity
3. Light Period
4. Carbon Dioxide Availability
5. Water Availability

How Gases Enter and Leave Plants

Other Pathways of Photosynthesis

1. The Calvin Cycle is the MOST Common Pathway for Carbon Fixation. Plant Species that fix Carbon EXCLUSIVELY through the Calvin Cycle are known as C3 PLANTS.

2. Other Plant Species Fix Carbon through alternative Pathways and then Release it to enter the Calvin Cycle.

3. When a plant's Stomata are partly CLOSED, the level of CO2 FALLS (Used in Calvin Cycle), and the Level of O2 RISES (as Light reactions Split Water Molecules).

4. A LOW CO2 and HIGH O2 Level inhibits Carbon Fixing by the Calvin Cycle. Plants with alternative pathways of Carbon fixing have Evolved ways to deal with this problem.

5. C4 PLANTS - Allows certain plants to fix CO2 into FOUR-Carbon Compounds. During the Hottest part of the day, C4 plants have their Stomata Partially Closed. C4 plants include corn, sugar cane and crabgrass. Such plants Lose only about Half as much Water as C3 plants when producing the same amount of Carbohydrate.

6. THE CAM PATHWAY - Cactus, pineapples have different adaptations to Hot, Dry Climates. They Fix Carbon through a pathway called CAM. Plants that use the CAM Pathway Open their Stomata at NIGHT and Close during the DAY, the opposite of what other plants do. At NIGHT, CAM Plants take in CO2 and fix into Organic Compounds. During the DAY, CO2 is released from these Compounds and enters the Calvin Cycle. Because CAM Plants have their Stomata open at night, they grow very Slowly, But they lose LESS Water than C3 or C4 Plants.