The oxygen bubbles accumulate in the leaf tissue, eventually making the disks buoyant again. The faster the disks rise, the higher the rate of photosynthesis. Common Lab Setup Variables
If you move floating disks to a dark area, they will eventually sink again. This is because the plant is no longer performing photosynthesis but is still performing cellular respiration , which consumes the oxygen stored in the leaf. Troubleshooting: Why didn't my disks float? floating leaf disk photosynthesis lab answers
ET50 = T₁ + ( (0.5N – N₁) / (N₂ – N₁) ) × (T₂ – T₁) where N = total disks, N₁ = # floating at T₁, N₂ = # floating at T₂. The oxygen bubbles accumulate in the leaf tissue,
“As light intensity increased, the ET50 decreased. Under 1000 lux, ET50 was 14 minutes; under 5000 lux, ET50 dropped to 5 minutes. This shows that higher light intensity increases the rate of photosynthesis, as oxygen production (causing disks to float) occurred more rapidly.” This is because the plant is no longer
Here, (because at 12 min, 6 out of 10 disks are floating).