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UNIT 2 QCE BIOLOGY PAPER
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CELLS AND MULTICELLULAR ORGANISMSSTUDENT EXPERIMENT E
11 BIOLOGY
Name: Noor Sidhu
Teacher: Miss Selsby
Word Count: Approx. 1489 excluding title page, content page, references, and appendices
,Table of Contents
Rationale...........................................................................................................................3
Modifications.....................................................................................................................3
Apparatus set up................................................................................................................4
Risk Assessment.................................................................................................................4
Raw Data...........................................................................................................................5
Analysis and Interpretation................................................................................................8
Evaluation..........................................................................................................................9
Conclusion..........................................................................................................................9
Improvements and Extensions..........................................................................................10
References.......................................................................................................................11
Appendices.......................................................................................................................13
What effect does the concentration of salt in a saline solution have on the transpiration rate
(and mass of water absorbed) on leaves with a large surface area, more specifically Cordyline
Fruticosa?
, Rationale
For plants to survive, photosynthesis is required as it provides energy for growth (Brenner, 2019). “In
order to cool the plant and deliver water and nutrients to the leaves for photosynthesis, transpiration
is necessary” (Wu et al., 2012). Transpiration is the loss of water as vapour from plants at their
surfaces, typically through stomata, which improves nutrient absorption into plants (Transpiration - an
Overview | ScienceDirect Topics, n.d.). More stomata will result in more transpiration pores. Due to
its greater number of stomata, a leaf with a larger surface area will transpire more quickly than a leaf
with a smaller surface area (W, 2019). A decrease in transpiration rate is caused by salinity (BAUM et
al., 2000). “The internal water potential of a plant cell is more negative than pure water; this causes
water to move from the soil into plant roots via osmosis” However, osmosis via plant tissues is not
possible in seawater as the salt solution actually pulls water from the plant causing it to dehydrate and
die (Lacoma, 2018). The ions of salt-forming soil minerals including sodium are absorbed by plant
roots and over time build up in the stem and leaves of the plant. These accumulated ions can become
toxic to plants, and ions like sodium, which impact osmotic pressure and potential by limiting water
flow to the plant, can be hazardous to plants even at low quantities. To test this research, an original
experiment allowed estimates for the rate of transpiration from a plant shoot. 3 different plants with
various surface areas were used and placed into a test tube with a layer of oil to eliminate evaporation
which was then left overnight. It was found that the plant with the larger surface area had the highest
rate of transpiration. Subsequently, a research question was formed to redirect the original
experiment: What effect does the concentration of salt in a saline solution have on the transpiration
rate (and mass of water absorbed) on leaves with a large surface area, more specifically Cordyline
Fruticosa?
Modifications
Original Experiment - Methodology used for Original Experiment
Modified Experiment
Salt concentrations was used in the water to create a saline solution which were 0.1, 0.2, 0.3,
0.4, and 0.5 to determine the rate of transpiration in correlation to salinity as a redirection of
the original experiment
Instead of different plants with varying surface area, the same kind of leaves with large
surface area so the results would rely solely on the salt concentrations for a fair investigation
improving reliability
3 trials were executed instead of just 1. "Repeated trials are conducted to reduce the effect of
errors and thus increase the reliability" (Scientific Inquiry: Measurement/Data, 2012).
To reduce human error, the measurement used for the inquiry was weight rather than water
level as scales have a lower uncertainty percentage than measuring cylinders and rulers.
Plants were placed outside in direct sunlight as light stimulates the opening of stomata which
allows diffusion of CO2 to carry out photosynthesis, so the rate of transpiration increases
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