Clean and dry the respiration
Rate of O2
Rate of O2
(|rate in the
light| plus |rate in
Biol 171L – FA15 Effect of Light Color on Photosynthesis 7-7
If the wavelength available to the plant affects
photosynthesis, then we would expect to see a difference in the photosynthetic rates
produced by the different colors of light, and therefore a measurable difference in the
amount of O2 produced during photosynthesis.
Total or GROSS photosynthesis, is the total amount of carbon fixed or oxygen
released by a plant in the light.
Photosynthesis Science Fair Projects and Experiments
Phycobilins absorb in
Biol 171L – FA15 Effect of Light Color on Photosynthesis 7-4
the green and orange portion of the spectrum and are important for allowing marine and aquatic
plants to harvest the wavelengths not filtered out by the water.
PHOTOSYNTHESIS AND RESPIRATION
The process of photosynthesis involves the use of light energy to convert carbon dioxide
and water into sugar, oxygen, and other organic compounds.
Does Leaf Color Affect the Rate of Photosynthesis
During this lab we wanted to determine if the color of the leaves affects the rate of photosynthesis. We hypothesized that if green leaves have a significantly higher rate of photosynthesis (consumption of CO2) than yellow leaves, because green leaves contain more green chlorophyll a and chlorophyll b photosynthetic pigments than yellow leaves, then the color of the leaves affects the rate of photosynthesis. We used a sealed chamber, in which we placed green and yellow leaves from the same tree, and measured changes in CO2 concentrations using a CO2 probe. We tested three replicates of each color of leaves for five minutes in the light to measure photosynthesis and respiration, and five minutes in the dark to measure respiration alone. By subtracting the light reactions from the dark, we found the rate photosynthesis alone. Our mean value for photosynthesis in the green leaves was -9.71 ppm/g and the mean value for the yellow leaves was -2.25 ppm/g. Our P value was .034. Overall, we failed to reject our hypothesis because our test results showed a significantly higher rate of photosynthesis in the chamber with green leaves than the one with yellow leaves. Although we failed to reject our hypothesis, we encountered a couple of problems while performing this lab, such as: we didnÄôt allow a substantial amount of time to air out the chamber between each trial and we used nearly half the mass of green leaves to yellow leaves.
Rose Nazarian & Shawn Murie
Photosynthesis can only happen in the presence of light
energy and chlorophyll.
We often think of
sunlight as a single
“white” wavelength, but
in reality it is a continuum
of wavelengths – each
wavelength representing a
different color of light.
Why the rate of Photosynthesis is higher in red ..
You will either measure the respiration/ photosynthesis rate of Elodea under two of
five colors of lights (blue, green, orange, red, and white) (Parts A & B); or, you will record the
absorption spectrum for Elodea (Parts C & D), and measure the respiration/ photosynthesis rate
of Elodea under one of five colors of lights (blue, green, orange, red, and white) (Parts A & B).
Each color of light (blue, green, orange, red, and white) represents one treatment.