Investigating Number of Stomata on a Leaf
Lab Design
“Investigate the effect of a factor on the number of stomata of a leaf.”
Research Question: How do differing leaf heights affect the number/density of stomata of a leaf?
Hypothesis
Stomata are pores, typically found under the leaf (lower epidermis), that control the gas exchange of transpiration, where water vapor leaves the plants, and carbon dioxide enters.
I predict that the stomatal density on high leafs is higher than on low leafs. During photosynthesis the chloroplasts in the leaf cells synthesize ATP from ADP as a result of exposure to light, while oxygen is produced as a by-product of the photosynthetic reaction. Carbon dioxide, which enters the plant through diffusion via the stomata, is needed for this process (photosynthesis) to occur. When the chloroplasts in the leafs cell is exposed to higher light intensities, more ATP is synthesized from ADP, while production of the by-product oxygen also increases. This increase in the rate of photosynthesis calls for more “fuel”, i.e. Carbon dioxide. So for a higher concentration of carbon dioxide to diffuse into the plant, the plant must grow a greater stomatal density (higher number of stomata). This will create a larger surface area for carbon dioxide diffusion, the excretion of water vapor (transpiration) and the large amounts of oxygen being produced.
As the higher leafs are exposed to higher light intensities I predict the stomatal density to be high. Lower leafs are exposed to lower light intensities due to, for example, shading by top leafs, and will so have a lower stomatal density than high leafs.
Variables
Controlled:
Type of plant- The type of plant that is going to be used will stay the same, i.e. controlled. The type of plant that is used for this experiment is called Quercus Ilex.
Amount of leafs (10 'high' leafs, 10 'low' leafs)- the ensure fair testing the number of leaves tested from each variable will be the same.
Apparatus used- Same set up each time.
“Investigate the effect of a factor on the number of stomata of a leaf.”
Research Question: How do differing leaf heights affect the number/density of stomata of a leaf?
Hypothesis
Stomata are pores, typically found under the leaf (lower epidermis), that control the gas exchange of transpiration, where water vapor leaves the plants, and carbon dioxide enters.
I predict that the stomatal density on high leafs is higher than on low leafs. During photosynthesis the chloroplasts in the leaf cells synthesize ATP from ADP as a result of exposure to light, while oxygen is produced as a by-product of the photosynthetic reaction. Carbon dioxide, which enters the plant through diffusion via the stomata, is needed for this process (photosynthesis) to occur. When the chloroplasts in the leafs cell is exposed to higher light intensities, more ATP is synthesized from ADP, while production of the by-product oxygen also increases. This increase in the rate of photosynthesis calls for more “fuel”, i.e. Carbon dioxide. So for a higher concentration of carbon dioxide to diffuse into the plant, the plant must grow a greater stomatal density (higher number of stomata). This will create a larger surface area for carbon dioxide diffusion, the excretion of water vapor (transpiration) and the large amounts of oxygen being produced.
As the higher leafs are exposed to higher light intensities I predict the stomatal density to be high. Lower leafs are exposed to lower light intensities due to, for example, shading by top leafs, and will so have a lower stomatal density than high leafs.
Variables
Controlled:
Type of plant- The type of plant that is going to be used will stay the same, i.e. controlled. The type of plant that is used for this experiment is called Quercus Ilex.
Amount of leafs (10 'high' leafs, 10 'low' leafs)- the ensure fair testing the number of leaves tested from each variable will be the same.
Apparatus used- Same set up each time.