Sources of Error:
Dry weight and fresh weight:
- When the plant was cut from the agar for measuring the fresh weight,
then sometimes the entire shoot may not be present. Also, the same part
of the plant was probably not cut each time. This would be a systematic,
procedural error; however, it will not play a huge role on the results,
since the difference between the plants will not be huge.
- A random, design error was that sometimes the plants were buried within
the agar which would have caused the plants to have an increased fresh weight
mass because there was no way to get rid of the agar without damaging the
plant.
- Another random, human error in this lab was that sometimes when measuring
the dry weight, bits of the plant became stuck on the sides of the test
tube.
Ethylene measurement:
- Ethylene is a gas and when it was stored in the syringes then it would
have escaped from the syringe. Also when it was injected from the 5ml syringe
to the 1 ml syringe, there was a possibility for some of the to escape into
the air. This was a systematic, design error, which cannot really be avoided,
since ethylene is a gas.
- Sometimes the syringes were broken without showing it on the outside and
thus the gas may have escaped due to that. This was a random, design error
and could be avoided or minimized, if all the syringes were tested by measuring
the peak produced; using a standard concentration of ethylene before each
time the syringes were used. However, this would have been very time consuming
and therefore could not be implemented.
- The ethylene measuring capability of the Photovac will change from the
first syringe to the last syringe sample. This is because the detection
capability of the Photovac decreases with each sample, but the standard
was calculated based on the first injections of the standard concentration.
Thus, the calculations would not be very accurate. This systematic, design
error could be avoided or minimized by testing with the standard concentration
each time; however, this would be extremely time consuming and the amount
of time needed to do that would be useless in comparison the amount of accuracy
gained by the implementation of that measure.
- Another systematic, design error was that the sizes of the 50 mmol/L and
the 75 mmol/ L plants were too small. Therefore, the ethylene produced by
these plants could be misleading because some of them were so small they
appeared to be dying.
