The Relation of Photosynthetic Rates to Leaf Location
By Adrianna Pulver, Nakoia Paewai-Bloch, and Alec Nelson
We tested the photosynthetic rate of leaves receiving direct sunlight (top of the plant) and leaves indirect sunlight (bottom of the plant) plant. Plants that grow in shady areas tend to have higher photosynthetic rates then plant in full sunlight because they have to utilize all the light they absorb. However, when you are looking at the same plant we questioned whether this would . Leaves at the bottom of the plant still photosynthesis, but not necessarily the leaves at the top of the plant, the location of the leaf on an individual plant determines the photosynthetic rate.
To test this hypothesis we began by collecting samples of leaves in direct and indirect sunlight. Next we weighed the samples and placed them in gas chamber with gas probe to measure the concentrations in logerpro. In each trail, we measured light and dark conditions of each sample subtract out respiration (Light-Dark) to get the photosynthetic rate of the leaves. These trials ran for approximately ten minutes each sample of leaves We predicted that leaves in full sunlight have a higher photosynthetic rate the leaves in partial sunlight.
Our results displayed no significant difference in the photosynthetic rates of leaves in direct sunlight and leaves in indirect sunlight. The mean value for the photosynthetic rate in full sunlight was -19.5625, while the mean value for the photosynthetic rate in partial sunlight was -15.4475. This failed to indicate any substantial difference in leaf location. Our t-test barely showed significant data. Our P-Value of .044
Kettle 2008 also focused on aquatic plant life and tested the reactions to different spectral resolutions and light absorption, indicat a sensitivity and higher photosynthetic rate then previously thought. nother study Vassiliev 2008 the light harvesting in photosystem II, focus more closely on the molecular reactions and conversion in photosystem II indicat significant variations among the photosystems I and II involving photochemicals and conversion rates. Considering these studies and our results we propose a revised hypothesis. Instead of the photosynthetic rate being determined by leaf location, the photochemicals and reactions to various light wavelengths is dependent on leaf location and that determines the photosynthetic rate. tudies indicate that there would a significant comparison between light wavelength reaction and photochemicals in leas in direct and indirect sunlight that would determine the photosynthetic rate.
Kettle, H. 2008. Modeling ocean primary production: Sensitivity to spectral resolution of attenuation and light absorption. Progress in Oceanography, 78:135-146.
Vassiliev, S. 2008. Toward understanding molecular mechanism of light harvesting and charge separation in photosystem II. Photosynthesis Research, 97:75-89.