Extracts from this essay...
Stomata Experiment Aim: To find out where stomata is mostly found in a leaf; in the lower epidermis or the upper epidermis. Stomata: Each stomata is a tiny opening in the leaf that can be opened and closed by two guard cells. Stomata allow gases to pass in and out of a leaf. When stomata are open carbon dioxide for photosynthesis can enter and oxygen can leave however water vapour can also diffuse out of the leaf. Hypothesis: I predict their will be more stomata at the lower epidermis because from previous knowledge I know water transpiration occurs fastest at hot, dry, windy conditions. Therefore at the lower epidermis there will be more protection against these conditions so less water will be lost.
Therefore in 1mm² there is 24÷ (14÷10) = 17.15 stomata per mm² for lower epidermis 1÷ (14÷10) = 0.714 stomata per mm² for upper epidermis Risk Assessment: Nail Varnish Wash any spillages with water Use small drops and don't overflow Conclusion: The results show that the stomata count is significantly high in the lower epidermis with 17.15 stomata per mm² unlike in the upper epidermis which I only found 0.714 stomata per mm². This shows me that my prediction was correct however I expected at least more stomata in the upper epidermis. A leaf loses water via transpiration in order to do this the guard cells are turgid which means the stomata is open. To be effective and also photosynthesise the plant would rely on a good supply of soil water.
The wind will be more effective upon the upper epidermis and therefore if more stomata were to be on the lower epidermis it will have more protection from the wind and therefore transpiration will be less. Therefore the results support my conclusion that at the lower epidermis there will be more protection against conditions that would increase transpiration therefore less water will be lost. Evaluation The limitations were - Didn't know the conditions of the leaf therefore couldn't give a detailed conclusion. Difficulties: - was hard to count up the stomata through a microscope therefore may not be accurate Improvements: - I would improve the experiment using more than one leaf for a stomata count - The stomata count was not a mean average so I need to repeat the experiment at least 3 times so results are reliable. ?? ?? ?? ??
Found what you're looking for?
- Start learning 29% faster today
- Over 150,000 essays available
- Just £6.99 a month
- Over 180,000 student essays
- Every subject and level covered
- Thousands of essays marked by teachers