The Effect of Concentration of CO2 on the Average Rate of Photosynthesis in Spinach Leaf Disks
School Name
Heathwood Hall
Grade Level
11th Grade
Presentation Topic
Botany
Presentation Type
Non-Mentored
Written Paper Award
1st Place
Abstract
The purpose of this experiment was to determine the effect of carbon dioxide concentration on the rate of photosynthesis in spinach leaves. Small circular disks were cut out of the spinach leaves using a standard hole puncher. Then solutions of differing concentrations of carbon dioxide, 0.2%, 0.4%, 0.6%, 0.8%, and 1.0%, were all prepared, and each solution was spread equally among five cups. There was also a control solution that contained only water. The gases were then sucked out of the spinach leaves with a syringe using a specific technique to create a vacuum. Ten leaf disks were then placed per cup per concentration, giving a total of 50 leaf disks per concentration. The cups were then exposed to light for 20 minutes, and the number of disks floating in each cup was measured every minute. Results were calculating by finding the ET50 for each concentration. The ET50 is the time it takes for 50% of the leaf disks to float and is a good indicator of the rate of photosynthesis. It was hypothesised that if the concentration of carbon dioxide was increased, then the rate at which photosynthesis will also increase. The null hypothesis was that the concentration of carbon dioxide will have no effect on the rate of photosynthesis. The results of the experiment supported the hypothesis. So, there is a direct relationship between CO2 concentration and the rate of photosynthesis.
Recommended Citation
Robinson-Brown, Amelia, "The Effect of Concentration of CO2 on the Average Rate of Photosynthesis in Spinach Leaf Disks" (2017). South Carolina Junior Academy of Science. 20.
https://scholarexchange.furman.edu/scjas/2017/all/20
Start Date
3-25-2017 11:59 PM
Presentation Format
Written Only
Group Project
No
The Effect of Concentration of CO2 on the Average Rate of Photosynthesis in Spinach Leaf Disks
The purpose of this experiment was to determine the effect of carbon dioxide concentration on the rate of photosynthesis in spinach leaves. Small circular disks were cut out of the spinach leaves using a standard hole puncher. Then solutions of differing concentrations of carbon dioxide, 0.2%, 0.4%, 0.6%, 0.8%, and 1.0%, were all prepared, and each solution was spread equally among five cups. There was also a control solution that contained only water. The gases were then sucked out of the spinach leaves with a syringe using a specific technique to create a vacuum. Ten leaf disks were then placed per cup per concentration, giving a total of 50 leaf disks per concentration. The cups were then exposed to light for 20 minutes, and the number of disks floating in each cup was measured every minute. Results were calculating by finding the ET50 for each concentration. The ET50 is the time it takes for 50% of the leaf disks to float and is a good indicator of the rate of photosynthesis. It was hypothesised that if the concentration of carbon dioxide was increased, then the rate at which photosynthesis will also increase. The null hypothesis was that the concentration of carbon dioxide will have no effect on the rate of photosynthesis. The results of the experiment supported the hypothesis. So, there is a direct relationship between CO2 concentration and the rate of photosynthesis.
