Leaves have numerous pores known as stomata on their surface. Stomata help the plants to take up carbon dioxide, which they use in photosynthesis or the process of food-making. Plants need stomata to release the oxygen formed during photosynthesis too. In short, without the stomata opening, plants cannot make food and will die. Are the stomata located above the leaf surface or below it? This vaseline on leaf experiment helps us to find out.
Materials Required
Small potted plant – 2
Vaseline petroleum jelly – 1 bottle
Area with sufficient sunlight
Steps to Follow
- Select two small potted plants. Make sure that they are reasonably healthy.
- Apply petroleum jelly on top of all leaves of the first plant (Plant 1).
- The top portion of leaves should be fully covered with it. In the second plant (Plant 2), apply petroleum jelly only underneath the leaves. Make sure that they cover the underside entirely.
- Keep both plants in an area with sufficient sunlight.
- Water the plants regularly.
- Observe the plants daily. Note down the findings in a chart.
- After a few days, you will notice that the plant with petroleum jelly on the underside of leaves shows signs of weakness.
- The plant with petroleum jelly applied on top of the leaves will remain healthy.
What we learn
In this vaseline on leaf experiment, you noticed that the plant with petroleum jelly underneath the leaves shows signs of weakness in a day or two. After a while, it will die. On the other hand, the plant with vaseline only on top of the leaves shows no weakness. What does this prove?
Stomata are located under the leaves. When petroleum jelly is applied underneath, stomata get completely blocked thereby preventing photosynthesis. The plant got water and sunlight, yet it died as it was not able to process food. When petroleum jelly is applied only on top of the leaves, stomata are not blocked. As a result, the plant was able to process food, and so it lived.
This interesting animated video will help you understand more about the process of photosynthesis and the role of stomata in it.
For more such interesting experiments, visit our Experiments section.
