Problem: Will spinach, a C3 plant, have a faster or slower photosynthesis rate than Agave (manipulated variable), a CAM plant; the duration of this experiment will last until all leaves have risen? Hypothesis: If C3 plants have a faster photosynthesis rate than CAM plants, then the spinach will have a faster photosynthesis rate than the Agave plant. Because CAM plants have closed stomas during the day, which is when the C3 plants’ stomas are open taking in CO2 and are going through photosynthesis, while the CAM plants are making malate. Procedure: The procedures are exactly the same as the AP Photosynthesis Lab 5 except we also did the same procedure, using spinach and we did the same procedure using Agave. Our controls were the cups with water and no CO2. Three factors that were controlled in the experiment were the light intensity (1 ft. from the cups); the number of leave cut-outs used each time (10), and the height of the liquid that was in each cup (3cm.). Observations & Data: The data shows that spinach had a faster photosynthesis rate than the Agave plant. During the experiment I observed that for the spinach in both trails 1 and 2 the leaves both began to rise at 4 minutes and had all ten leaves rise by 20 minutes. Also for the spinach I observed that there was one leaf in the water cup rise for trial one while none had rose in trial 2, which is a good sign because it means that we were successful in getting all of the air out of the leaves. In both of the trials with the Agave plants both had their ET 50 at 30 minutes and they also both had none of the leaves in the water cup rise. Analysis: The data shows that C3 plants have a faster rate of photosynthesis than CAM plants do. The variable, Agave plant, a CAM plant was used to compare to the C3 plant, spinach. The trials for spinach had an ET 50 at 7 min (trial 1) and at 10 min (trial 2) while the Agave had an ET 50 at 30 min for both trial 1 and 2. This is because C3 plants have open stomata during the day and it is because they are more efficient than CAM plants under cool and moist conditions and normal light because they require
