Question 19N.3.HL.TZ0.2
| Date | November 2019 | Marks available | [Maximum mark: 5] | Reference code | 19N.3.HL.TZ0.2 |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Describe, Explain, State, Suggest | Question number | 2 | Adapted from | N/A |
A student designed an experiment to study the transpiration through the leaves of a tomato plant (Solanum lycopersicum). Measurements were taken in the initial conditions with five leaves on a tomato shoot and then again after each of the five leaves was removed.
[Source: R. C. Hodson and J. Acuff . 2006. Water transport in plants: anatomy and physiology in
Tested Studies for Laboratory Teaching, Volume 27 pp 163–183]
Describe the trend in the data.
[1]
negative correlation between the number of leaves removed and transpiration rate Do not accept type of correlation alone, as a description is required.
OR
as more leaves are removed the transpiration rate drops ✔ OWTTE
Transpiration continued after the fifth leaf had been removed. Suggest what can be concluded.
[1]
transpiration does not only occur in the leaves
OR
transpiration through stem/shoot ✔
State the independent variable in this investigation.
[1]
number of leaves «removed» ✔
Explain how the results in the graph could have been obtained.
[2]
a. using a potometer ✔ Accept transpirometer but not respirometer.
b. leafy shoot attached to a reservoir and a graduated «capillary» tube ✔
c. as transpiration increases water uptake «by roots» also increases ✔
d. distance/time for bubble «in capillary tube» to travel is used to measure transpiration rate ✔
