Effects of Gas Exchange Rates Between C3 and C4 Plant Species

Spinach and basil (C3 plants) were compared with corn (C4 plant) to explore how photosynthetic pathways affect CO2 consumption. Corn seeds were obtained and planted in Miracle-Gro® soil to be observed over the duration of a month. Leaves (starting from 3,4, and 10) from each plant were then taken and placed into a bottle and closed off with a CO2 gas probe that measured levels of carbon dioxide in ppm. Spinach and basil leaves were used as a comparison for measuring the rate of CO2 concentration. This is done to compare the gas exchange rates between C3 and C4 plants. The stomatal area/leaf area were recorded from each plant as well. Additionally, chlorophyll was extracted from the C3 plants to determine if there were any differences among CO2 rates. Our null hypothesis is that plants that differ in photosynthetic pathways (C3 and C4) will have similar CO2 consumption rates. Our alternative hypothesis is that plants that differ in photosynthetic pathways will have significantly different CO2 consumption rates. CO2 levels declined more amongst C3 plants, attributing the higher chlorophyll content.