Photosynthesis Rate Lab Report

The purpose of this lab was to investigate whether veins affect photosynthesis rate. It was predicted that having veins would decrease the rate because chloroplast might be less frequent due to the vascular tissue. For this experiment, 4 groups were set up: veins and no veins in CO2 solution, and veins and no veins in distilled water, the distilled water groups served as controls. These 4 groups were placed under a light bulb in order for photosynthesis to occur. No disks experience movement in the first 7 minutes but at the 8 minute mark, 2 disks from the no vein CO2 group floated. This showed that no veins could have possibly provided a head start due to some disks having a higher number of chloroplast present to perform photosynthesis compared
to the no vein group that had fewer surface area containing the chloroplast. Having less chloroplast would mean a slower photosynthesis rate. As the time continued, veins with CO2 had its first floating disk at 10 minute and the disks in the no veins CO2 group continued to rise at a steady rate.
They reached equilibrium at 11 minutes when both had a total of 4 floating disks. This showed that although no veins CO2 had a head start, vein CO2 increased at a higher rate. This data contradicts the hypothesis because having veins was believed to decrease the photosynthesis rate, but instead, veins did not cause significant discrepancy between the rate. This could be due to some veins being so small that its impact was negligible. By the 16 minute mark, the veins with CO2 group leveled out at 9 while the no veins with CO2 reached 9 floating disks at 20 minutes. The other two groups that had no CO2 did not experience any movement due to the lack of carbon, a raw material necessary to carry out photosynthesis The experiment ended at the 20 minute mark due to the lack of time. With both group reaching 9 floating disks within 20 minutes, it could be concluded that veins do not significantly alter photosynthesis rate. This could be due to the small vein size that does not take up the majority of the disk’s surface or due to mistakes performed during the experiment. One possible error is that not all the veiny disks had the same amount of
veins. With some having more veins and others having less, the data becomes less accurate because variability has increased. The disks with more veins could of had a slower photosynthesis rate than the ones with less vains. Another error could be the misplacement of the disks. While punching out 60 disks, some non veiny disks could have possibly landed in the veiny pile. This error could have increased the photosynthesis rate of the vein in CO2 experiment because the non veined disks skewed the data. Lastly, the placement of the cups under the light could have made the data collected less reliable. The veins in CO2 cup was placed closer to the light than the no veins in CO2 cup. Higher intensity of light might have caused photosynthesis rate to be higher in the vein cup. If both cups were placed in the same area, the data collected could have been different.