-1Determining the water potential of potato tuber cells.
Requirements:
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A large raw potato tuber
●
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Sucrose solution of concentrations: 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 mol dm-3
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1 X 6 boiling tubes with stoppers ●
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Cutting Board
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balance (weighing internal of 0.001g)
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Absorbent tissue paper
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a marker pen
cork borer (10 mm diameter)
scalpel blade
● forceps
Procedure:
1.
Sucrose solution of different molar concentration (0.0, 0.2, 0.4, 0.6, 0.8,
1.0 mol dm-3) is provided. Pour equal quantity of each solution in different
boiling tubes. Label the six boiling tubes appropriately.
2.
Trim the raw potato provided at both ends using a knife. Using a cork
borer, cut out 30 potato strips from the large potato. Using a blade and a
ruler, trim the strips to the same length, about 50 mm, divide the strips into
6 sets of five strips each.
3.
Mark 5 strips of each set for identification with the marker pen. Take the
mass of each strip and note it down. Put these strips in one boiling labeled
0.0 mol dm-3.
4.
Repeat the above step for each of the remaining solutions (0.2, 0.4, 0.6,
0.8, 1.0 mol dm-3).
5.
After at least 30 minutes, remove the strips from their respective solutions,
mop up any excess solution using a blotting paper, measure and record
the weight of each strip.
6.
Observe and record any other relevant data.
7.
Process and present your results using appropriate tools. The attached
table (table 2.1) could be used to estimate the water potential of sample
potato cells.
Assessment criteria: DCP & CE
-2-
(Tim King 2001)
Reference:
Tim King, Michael Reiss & Michael Roberts. Practical Advanced Biology. Cheltenham United
Kingdom: Nelson Thornes, 2001.