Stomata Investigation

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Stomata Investigation

The following experiment included an investigation into how the location of a leaf from a specific plant may effect its density of stomata on the lower epidermis. Stomata are one of the internal factors, which affect the rate of transpiration.

It was hypothesised that leaves on the outer edge of a plant or tree would have a higher density of stomata due to environmental factors such as availability of light and air movement.

The leaves used for the experiment were taken from a Holly tree, biologically referred to as Ilex.

Materials:

* Ilex- taken for experimental purposes ( 5 exterior and 5 interior)

* Forceps- to remove impression

* 10 Microscope slides and cover slips- for viewing under microscope

* Video Microscope monitor- to observe and count stomata

* Labels- for identification

* Graph paper- outline drawing of leaf samples

* Stage micrometer- measure the field view through microscope eyepiece

* Pencil, Calculator, Ruler

Method:

. Materials are laid out on a single table for the easy access

2. Leaf samples are taken from the Ilex tree. 5 leave's taken from the outer edge and 5 from the plant inner part of the tree.

3. Leaves are placed on graph paper and carefully outlined.

4. 3 coats of nail varnish are applied to a 2cm by 1cm area on the lower epidermis of the leaves. Varnish is left to air dry completely.

5. Slides are labelled with a specific number and letter for identification. The number indicates the leaf sample number and the letter, the location taken from (exterior-E, interior-I) e.g. S1:E

6. Using the forceps, the varnish impressions are peeled off and adhered to appropriate slides and a cover slip is applied.

7. Unneeded materials are packed away to avoid congestion.

8. Each slide is viewed in a 0.216mm field of view under a magnification of (x10)

9. Observing the screen, visible stomata are counted and recorded. This procedure is repeated 5 times to obtain reliable results.
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0. A labelled drawing of a stoma and its surrounding is drawn from a sampled leaf.

* Analysis of Results

The results are illustrated using a Bar chart, which compares values across categories. The graph represents only the total number of stomata counted from the area tested (2cm by 1cm), as to plot all the counts attained would require a much larger bar chart. This may have made any trends or patterns shown misleading.

From the Figure 3, 4 out of the 5 tests for the interior samples show to have a higher density of ...

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