Core practical title: Looking at plant stems
Aim: To observe xylem vessels, phloem sieve tubes and sclerenchyma fibres within the plant stem and locate
the position as well as develop practical skills including microscope use and measuring using an eyepiece
graticule
Apparatus:
Piece of stem from a plant (rhubarb) We need this as the stem which we will be observing
will come from this plant, we will aim to observe cell
structures within the plant stem e.g., xylem and
phloem
Sharp scalpel The scalpel is used to ensure that a thin tissue of the
rhubarb plant cell can be extracted, as a thick piece
of stem can make it harder to see the vascular
structures via the microscope e.g. xylem and phloem
Watch glass The watch glass is used to transport the rhubarb
piece onto the station where the experiment is
taking place, it can also be used as a foundation for
the scalpel to extract a thin piece of tissue from the
plant stem
Cover slip The cover slip is used to protect the microscope as
its objective lens might come in direct contact with
the specimen, and also creates an even thickness for
viewing, it can also be used to flatten the specimen
for easier viewing
Eye piece graticule The eye piece graticule is necessary as after
calibrated it can be used to make measurements of
any tissue or structures that can be viewed with the
microscope on that exact magnification, this is
calibrated to the stage micrometre at each
magnification
Methylene blue/ glycerol The dye is used to stain the specimen to help
identify certain cellular components under the
microscope clearer, the staining helps increase the
contrast between the organisms and the
background so they are easier to see in the light
microscope
Microscope/ slide The microscope is used to observe the plant cells at
a cellular level, used to magnify small objects/
specimens which certain structures cannot be seen
to the naked eye, the microscope is used to view the
structures within the plant stem.
Filter paper Use the filter paper to help absorb excess dye or
glycerol added
Method:
1. Put a small piece of rhubarb on a watch glass in order to use the forceps or scalpels to extract one or
two vascular bundles from the tissue and ultimately place them on a microscope slide
2. Use the scalpels to tease the vascular bundles apart and then cover the tissue with a drop of
methylene blue (can use a pipette) and wait for 5 minutes to the specimen can fully absorb the dye
3. Draw off the extra stain with the filter paper and then place a drop of dilute glycerol on the fibre
extracted so the glycerol can help the specimen be observed clearer under the microscope and then
mount under a cover slip