Everything Life Sciences Grade 10

Structure

Figure 5.7: Stomata in a tomato leaf as seen

under a scanning electron microscope.

Figure 5.8: The above is a microscopic im-

age of anArabidopsis thaliana(commonly

known as ‘Thale cress’ or ‘mouse ear’)

stoma showing two guard cells exhibiting

green fluorescence, with chloroplasts stain-

ing red.

Activity: Practical investigation of leaf epidermis

Materials:

• leaves of Agapanthus, Wandering Jew(Tradescantia) or similar plants that have epi-
  dermis that strips off easily


• microscopes


• microscope slides and cover slips


• dissecting needles


• scissors

Instructions:

1. Rip a piece of leaf lengthwise and check for ”thinner bits” near the edges, which will
   be epidermal tissue (ensure that you have LOWER epidermis because this is where the
   guard cells are found.)


2. Use the scissors to cut off a small section of epidermis and mount it in water on a
   microscope slide. Cover with a cover slip.


3. Focus the slide on low power and search for a section of the sample that does not have
   air bubbles over the stomata.


4. Enlarge the part of the specimen you chose and focus on high power.


5. Adjust lighting if necessary and draw one stoma and its guard cells. Label all parts.

Questions:

Chapter 5. Plant and animal tissues 121