Handling Plants Safely in Science
Introduction
If you're not a microbe and you're not an animal, chances are you are a
plant. Studying plants is an exciting activity for students.
Students will carry out many activities with plants in the laboratory. This activity is
not completely risk free.
Working with plants in the laboratory presents potential hazards for students.
Guidelines for safe use of biological materials require that safe practices and
procedures be in place to reduce or eliminate these exposure risks.
Identified Risks and Hazards
Plant viruses, bacteria, fungi will lead to infection.
Plant poisoning due to inhalation includes:
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vapors
dust
mists
gases
biological agents
Ingestion from contaminated hands or by incidentally contaminated
Utensils/cups/water bottles.
Inoculation from accidental needle sticks injury.
Allergic reactions
Pre- operational Safety
Lab coats protect your clothes and your skin in the event of a reagent spill. They
also help you avoid bringing contaminated clothing into your home.
Wearing correct gloves and hand washing helps to protect you from hand
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contamination and eliminating the risk for toxicity.
Wear appropriate footwear.
Goggles should be worn to protect you from possible splashes.
Eye protection should be worn at all time in the lab areas.
Masks will protect you - but only from particles/dust or aqueous mists that do
NOT emit harmful vapors.
Laboratory Environment
For plants, an adequate supply of soil of the appropriate composition, as
specified in the protocol, should be available as needed.
Improving the safety of the work environment through the following;
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recognition, evaluation, and control of hazardous conditions such as
inhalation, ingestion, and contact of poisonous plants
provision of necessary facilities which include proper lighting, proper
ventilation, and water and nutrients
clean containers should be available for use
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Operating Safely
Working with plants
Wash your hands after working with seeds and plants. Many store-bought seeds
have been coated with insecticides and/or fertilizers.
Never put seeds or plants in the mouth.
Do not handle seeds or plants if there are cuts or sores on the hands.
Some 700 species of plants are known to cause death or illness.
Be aware of plants in the local area that are harmful.
Be aware of the signs of plant poisoning and act quickly if you or a
student exhibits such signs after a lesson. Symptoms may include one or more of
the following: headache, nausea, dizziness, vomiting, skin eruption, itching, or
other skin irritation.
Extraction of Chlorophyll
In the extraction of chlorophyll from leaves with hot alcohol, care must be taken
to minimize fire risk. Use alcohol only in the absence of naked flame.
When using other flammable solvents for extracting chlorophyll for
chromatography, the same precautions should be taken.
Free-hand Sectioning
In free-hand sectioning of plant specimens, care should be taken when holding a
razor to prevent cutting your fingers.
Do not use rusted or blunt razors. Handle double-bladed razors with special care.
Macerating, Fixing, Mounting and Staining
Macerating fluids can be harmful, corrosive or flammable.
Appropriate care should be taken. The safety considerations should also be
taken when handling fixatives and stains.
Some chemicals can only be handled in a fume cupboard and not in open areas.
You should wear protective gloves when necessary.
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Using Microscopes
Microscopes are expensive, precision instruments with parts that easily get out of
alignment. Even the slightest misalignment will greatly affect image quality and
detract from your lab experience. Handle them with care!
Always carry the microscope upright with two hands.
Place microscopes gently on the lab bench, never near the edge, and never slide
them across the table. Position it for easy access by both lab partners and the
instructor.
Carefully position electric cords to avoid tripping or having the microscope pulled
off the table.
Clean all lenses with lens paper. Never use paper towels.
Turn on the illuminator, rotate the turret or nosepiece so no objective is over the
stage opening, and place the slide within the clips, and position specimen over
the center of the opening using the stage adjustment knobs.
Rotate the low power objective into place (it should click) over the slide.
Watching from the side use the coarse focus knob to position the objective as
close as possible to the specimen.
While looking through the ocular focus downward with the coarse focus knob
until the specimen is in focus. Never focus upward with the coarse focus.
Use the fine focus knob to obtain a sharper focus. Always make sure the
specimen is in focus under low power before moving to a higher power.
Regulate the light intensity with the iris diaphragm. Some microscopes have
adjustable light sources as well. You may also need to move the sub stage
condenser up or done to adjust the focal point of light passing through the
condenser lens.
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Prior to increasing magnification make sure the area to be magnified is in the
center of the field of view. While watching from the side, rotate the next highest
power objective into place. Make sure that it does not contact the slide.
Adjust the fine focus to sharpen the image. Never use coarse focus once you
leave low power.
Before removing the slide always return to low power and move the objective
away from the slide with the coarse focus knob.
When finished clean the lenses with lens paper, coil the electric cord, replace the
cover, and return the microscope to its appropriate place in the storage cabinet.
Storage of microscopes
Always cover the microscope with the supplied dust cover when not in use
Store in a dry place In humid or moist environments, it is advisable to store the
microscope in a waterproof container with a drying agent
Do not touch the optical lens with bare fingers
Do not store the microscope in direct sunlight. Sunlight can influence the quality
of the specimen imaging.
Maintenance
Storage and Housing of plants
Plant care requirements are usually far less demanding than animal care and
include:
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Facilities necessary include proper lighting, adequate heat, and water and
nutrients.
Containers should be clean before use.
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Commercial potting mixtures are recommended over garden soil because
they are sterile.
Cleaning of plant habitats.
Clay pots should be scrubbed and then soaked in a 10% bleach solution
before reuse. This is especially true when experiments are being
conducted to avoid contamination factors.
Operating Procedures
Allergic reactions
Supervisors should be aware that some students may be allergic to pollen,
spores or other airborne plant exudates.
Precautions to prevent dispersal should be taken to minimize exposure.
Students who are known to be hyper-sensitive to pollen should not be
encouraged to handle flowers.
Proper precautions should be taken when working with flowers.
Disposal Exotic plants
These plants should never be released into the environment where they may
compete with local plants. They can severely upset the balance in nature.
Native plants
These plants normally should not present a problem for the local environment
and should be disposed of in a manner consistent with school policy.
General precaution
Students should be warned not to ingest any plant materials used in
experiments because some of them are poisonous (e.g. castor oil seeds), or
contaminated with fungicides, pesticides, pollutants or spoilage microorganisms.
The plant materials may also be contaminated during experiment. Thus, remind
students to wash hands after handling plants.
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Students should be made aware of poisonous plants and be able to identify any
such plants on sight.
Keep plants known to contain irritants inaccessible to students, as the
substances may cause an allergic reaction.
When dealing with plant specimens that bear spines or thorns, care must be
taken. Wear suitable protective gloves when necessary.
When working with plants never place any parts of the plant in your mouth or rub
the sap or fruit juice on the skin or into an open wound.
Avoid inhaling or exposure of the skin and eyes to the smoke from any burning
plant or plant part.
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