Photosynthesis LabLeaf Disc Assay

G Block

Anupama Balasubramanian, Kai-Lou Yue, Diana Zhou, Angela Lee

Comparison of the Photosynthetic Rate of Spinach and Mint

In the experiment, we found that the photosynthetic rate of mint was far higher than the rate of spinach, proving our hypothesis incorrect. The photosynthetic rate of mint was 0.028 floats per second (10 chads by 6 minutes), and the rate of spinach was 0.003 floats per second (10 chads by 10 minutes). Sources of error in the experiment may include not covering the mint and spinach leaves quickly enough, so they might have started to photosynthesize before we were ready. Additionally, only one trial was conducted, so this is sure to provide less reliable results. This lab explores photosynthesis, which we are learning in class. We also learned about pigments, especially chlorophyll, which collect energy from sunlight in photoautotrophs, and the way in which light energy is obtained from the leaves by reflecting certain colors of light on the visible light spectrum and absorbing others.

Hypothesis: If mint and spinach leaves are similar shades of green, then their photosynthetic rates will be similar.

Andrea, Janice, Aubrey, Katie

The rate of photosynthesis for the spinach leaf chads is clearly greater than that of the bamboo leafs chads. This result aligns with our hypothesis of the spinach having a faster rate. This faster rate is due to its greater amount of chlorophyll, which is indicative in the spinach’s leaf darker green color.

Comparison of Photosynthetic Rates of Spinach and Bok Choy Leaves

Overall, we found that photosynthesis occurs faster in spinach leaves than in bok choy leaves, concluded from the faster rate of floats per second. The spinach leaves probably have more chlorophyll, meaning that the spinach leaves can absorb more light, causing the LD reactions occur faster.

Spinach-- .0357floats/1secBok Choy-- .0238floats/1sec

By Steph Miller, Kayla Chavier, Emily Wu, and Saif Khan

Leaf Disc Assay~ Lab Results:Time (min)

0 min

1 min

2 min

3 min

4 min

5 min

6 min

7 min

8 min

9 min

10 min

Spinach

0 0 2 5 11 13 - - - - -

Dracena Plant

0 0 2 2 2 3 - - - - -

Lamp Voltage: 200V

Rate of Floating Leaves:Spinach: 2.6 floats/minDracena Plant: 0.6 floats/min

Overall, the spinach had a faster reaction rate than the Dracena plant. However, there may have been a failure in the experimental design to account for the waxy cuticle of the Dracena plant leaves, since it might have prolonged the release of oxygen bubbles.

Control Graph

Oak Leaf Graph

Hypothesis

If spinach and oak leaves are tested to find their photosynthetic rates, then spinach will have a higher rate because it has a darker green pigment containing more chloroplasts for photosynthesis, and the oak leaves are breaking down and have more veins.

Notes● Our hypothesis was accepted, the spinach leaves had a faster

rate of photosynthesis. All 14 leaf chads floated within five minutes.

● Only 3 out of the eight oak leaves that sank floated within five minutes.

Pictures

Dan, Satish, Rohitash, and Kevin● From our data we observed that the experimental plant, mint leaves, carried out a faster rate of

photosynthesis, with .08 floats/sec than the control plant, spinach, with a slower rate of .05 floats/sec.● This supports our hypothesis because we stated that the experimental plant, mint, will photosynthesize

faster than the control plant, spinach.● The mint discs floated more suddenly, as indicated by the higher rate. The spinach discs were slower to

float up, but eventually would reach the top. By half this time though, all of the mint discs were already floating