Study of distribution of stomata

Materials Required

Real Lab Procedure

  • Pluck one fresh leaf of a four-o’clock plant.
  • Take two watch glasses and pour some distilled water into the both watch glasses.
  • Split the leaf from the four-o’clock plant obliquely.
  • Take the peel from the upper surface of the leaf using the forceps.
  • Place the peel into a watch glass containing water.
  • Take another peel from the lower surface of the leaf using the forceps.
  • Place the peel into the other watch glass containing water.
  • Using a dropper, take few drops of Safranin solution and put it into the two watch glasses.
  • Take two clean glass slides and place the leaf peel on the slides one by one, using a brush.
  • Take a blade and cut a small rectangle or square piece from each peel.
  • Take some glycerine using a dropper and put one drop of glycerine on both slides.
  • Take a cover slip and place it gently on the peel with the help of a needle.
  • Take the glass slide and place it under compound microscope.
  • Observe under the microscope.
  • Count the number of stomata in the peels of both upper and lower epidermis of the leaf appearing in the microscopic field.

Simulator Procedure (as performed through the Online Labs)

  • You can select the type of view from the ‘Select view’ drop down list.  To view the leaf structure, select  the 'Binocular view' .
  • You can select the slide containing the leaf from the ‘Select sample’ drop down list.
  • The power of the lens can be changed by selecting the required lens power from the drop down list ‘Select objective lens’.
  • To coarse focus on the tissue, you can move the tube up and down by clicking on the ‘Coarse adjustment’ right and left arrow.
  • To achieve a fine and sharp focus, you can move the tube very slowly by clicking on the ‘Fine adjustment’ right and left arrow.
  • You can move the slide to observe each part of the sample by clicking on the directional arrow of the ‘Slide adjustment’.
  • Count the number of stomata and epidermal cells in the specimen and enter the values into the corresponding text boxes on the left pane.
  • It will calculate the stomatal index and show into ‘Stomatal Index’ textbox.
  • To repeat the experiment, click the ‘Reset’ button.

Observations

  • The number of stomata is greater in the lower epidermis, and fewer are present in the upper epidermis of the leaf taken from a four-o’clock plant.

Precautions

  • The curling of the peel should be avoided.
  • Always use a brush to transfer the peel from watch glass to the slide

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