Everything Life Sciences Grade 10

Table 5.2: Structure and function of parenchyma

Activity: Observing parenchyma cells.

Aim:

To observe the structure of fresh parenchyma cells

Materials:

• banana


• petri dishes or watch glasses


• dissection needles


• iodine solution


• microscopes, microscope slides and cover slips

Instructions:

1. Use the dissecting needle to lift off a small piece of the soft banana tissue.


2. Put the sample onto a petri dish or watch glass and mash it slightly using the dissecting
   needle (and a pencil if you want).


3. Lift a small sample of the tissue onto a microscope slide on which you already have
   placed a drop of iodine solution. Put the cover slip on.


4. Observe the cells under low power and find a section where the cells are lying sepa-
   rate, not all over each other.


5. Enlarge this section and focus carefully to see if you can find nuclei in some of the cells
   (they will be bigger than the purple plastids and transparent).


6. Draw 2 or 3 cells and label.

Questions:

1. Describe the shape of the cells and their wall thickness.


2. What are the plastids called which appear purple and what is their function?

Collenchyma tissue DUMMY

Collenchyma is a simple, permanent tissue typically found in the shoots and leaves of plants.
Collenchyma cells are thin-walled but the corners of the cell wall are thickened with cellu-
lose. This tissue gives strength, particularly in growing shoots and leaves due to the thickened
corners. The cells are tightly packed and have fewer inter-cellular spaces.

Chapter 5. Plant and animal tissues 123