Dissection and microscopy of plant vascular
tissue
Student Sheet
Introduction
The aim is to obtain a very thin cross-section of plant tissue that is cut completely
perpendicular to the length of the specimen and to get this section to lie flat on a
microscope slide. The section is either stained or left unstained and mounted in water
with a coverslip on top, ready for viewing under a microscope. Once under the
microscope you should produce a scientific drawing of a vascular bundle with a scale
bar.
This practical provides the opportunity for skills development in the use of a light
microscope and graticule, the use of instruments for dissection and scientific drawing.
Safety notes
Your teacher will provide you with a blade – either a scalpel or razor blade. These are
very sharp so that you can obtain very thin sections of plant tissue. Handle these blades
with care.
Wear eye protection when using the Toluidine blue stain.
Instructions
1. Obtain a stick of celery (Apium graveolens var dulce) about 5cm long.
2. Rest the stem horizontally on a white tile and use a blade to cut one end as
perpendicular to the length of the stem as possible.
3. Now use the blade to cut very thin slices of the celery from the edge you’ve just
cut.
4. Use forceps to gently lift the slices into a small beaker containing tap water and
leave to soak for 2 minutes.
5. Use forceps to gently lift the slices into a watch glass containing toluidine blue
and leave the slices in the stain for 1 minute.
6. Use forceps to gently lift the slices back into tap water to rinse off excess stain.
7. Place the slices on a microscope slide. Add a drop of tap water and a coverslip
onto each slice.
8. View under the lowest magnification.
9. Find the clearest view that shows a variety of structures within the stem and
produce a scientific drawing of what you see. Use the graticule to add a scale bar
and work out the magnification of your drawing (see “Box 1: Using a graticule” at
the end of these practical instructions).
10. View under a higher magnification and find the clearest view that shows one
vascular bundle.
11. Produce a scientific drawing of what you see. Use the graticule to add a scale
bar and work out the magnification of your drawing.
Science & Plants for Schools: www.saps.org.uk
Dissection and microscopy of plant vascular tissue – student notes: p. 1
Resource 1325, Version 1.1 (revised 2019)
This method can also be used to get longitudinal sections of celery:
1. Obtain an approximately 2cm long piece of
celery stalk (petiole).
Use this
2. Stand the stalk vertically on a white tile and
bit
use a scalpel
to cut vertically down through one vascular
bundle.
3. Continue the protocol from step 3 above.
Cut here
Colours shown in sample after staining with toluidine blue
Tissue / type of cell wall
Colour
Xylem
Green/Blue-green
Phloem
Purple/Red
Sclerenchyma
Blue-green/ Green
Collenchyma
Purple/Red
Parenchyma
Purple/Red
Lignified cell walls
Green/Blue-green
Unlignified cell walls
Purple/Red
Box 1: Using a graticule
Use an eyepiece graticule that is 10mm in length with each mm divided into 10 parts. This
means that each small division is 0.1m or 100µm.
The image of the specimen is magnified by the objective lens onto the graticule so the size
for each small division is dependent of the magnification of the objective lens.
Objective lens
Size of each
magnification
small division /
µm
x4
25
x10
10
x40
2.5
x100
1
You can use the values for the size of each small division to measure the actual size of
parts of your specimen.
Once you have done a drawing you can work out its magnification by measuring the size
of part of the image (with a ruler but convert into µm) and dividing this value by its actual
size (as identified using the eyepiece graticule).
Once you have worked out the magnification of your drawing you can draw a scale bar by
picking the size you want to represent in the scale bar (e.g. 10µm) and multiplying this by
the magnification to give you the length (in µm) of the line you need to draw.
More accurate measurements:
Microscopes vary so for more accurate measurements you would need to calibrate your
eyepiece graticule using a stage micrometer.
Science & Plants for Schools: www.saps.org.uk
Dissection and microscopy of plant vascular tissue – student notes: p. 2
Resource 1325, Version 1.1 (revised 2019)
Questions
1. Answer the following questions about the method you used
a) What species did you investigate?
b) Why is it important to produce very thin slices of plant tissue?
c) Why is it important that the sections are truly cross-sections and not cut at an
angle?
d) What did you find was the best way to get sections as thin a possible?
e) Why are stains useful in microscopy?
f) Why is toluidine blue useful for this protocol?
2. Your scientific drawings
a) Give the drawings titles to describe the specimen, the staining procedure and the
magnification of the eyepiece and objective lens used.
b) Label the drawings to show different cell types and cell structures.
c) Annotate the drawings to provide more information about what you have labelled.
d) Provide a scale bar and magnification for the drawing you have produced.
3. The biology of what you see
a) How can you tell if what you are looking at is a xylem vessel?
b) What adaptations do xylem vessels have? Which adaptations can you see in
your preparations and how?
c) How are the features of xylem vessels linked to their function?
d) How can you tell if what you are looking at is phloem?
e) Can you identify the difference between sieve tube elements and companion
cells? If so how? If not what is the difference between the two and how might you
be able to identify one from the other?
f) Where are the phloem in a stem compared to the xylem?
g) What adaptations does phloem have? Which ones can you see in your
preparations and how?
h) How are the features of phloem linked to their function?
Science & Plants for Schools: www.saps.org.uk
Dissection and microscopy of plant vascular tissue – student notes: p. 3
Resource 1325, Version 1.1 (revised 2019)