AP Biology: Plant Tropism Lab
Introduction (for both parts together): Tropisms in plants, including action of hormones
Part One: Gravitropism in Bean Sprouts
Hypothesis: How will different orientation of seeds affect sprouting/growth of shoots
and roots as a bean germinates?
Methodology: Plant 8 seeds in 4
orientations, inside CD case. Use moist
cotton balls and a paper towel to hold
beans in place. Water and check seeds
daily—measure growth, make sketches in
notebook, and take pictures with camera
phones. Continue for 5-10 days.
Data: Every day make a note of what you are seeing, which must include rough sketches
in lab notebook. Photos are acceptable only for PowerPoint slides. Measure length of
root/shoot and note directionality. Notebook should include measurements,
observations, and sketches for the data section of this lab.
Analysis: Graph growth (shoots, roots), calculate growth rates
Conclusion: Effect of gravitropism on germinating bean seeds in different orientations.
- Rejecting/not rejecting hypothesis
- Connection to course material
- Suggested modifications to methodology or additional testing
Part Two: Phototropism in Bean Plants
Students will design their own experiment using shoe boxes to explore the effect of
phototropism on plant growth. Bean sprouts should be transplanted into small cups,
which should be placed in growth chambers (shoe boxes).
Hypothesis: How will phototropism affect the
growth of bean plants when placed in speciallydesigned growth chambers?
Methodology: Will vary, but students should
transplant bean plants from Part One into small
cups (with potting soil). Groups should design (and
construct) various growing chambers in shoe boxes,
which will somehow test the effect of phototropism
on plant growth (care should be taken to design at
least one control box). Water and check plants
daily—measure growth, make sketches in notebook,
and take pictures with camera phones. Continue for
2-3 weeks.
Students are responsible for designing and
building their own chambers, supplying their own
materials.
Data: Every day make a note of what you are seeing, which must include rough sketches
in lab notebook. Photos are acceptable only for PowerPoint slides. Measure amount of
plant growth and note directionality (lateral and/or apical). Notebook should include
measurements, observations, and sketches for the data section of this lab.
Analysis: Graph growth, calculate growth rate
Conclusion: Effect of phototropism on bean plants
- Rejecting/not rejecting hypothesis
- Instead of answering lab questions, comment on class PowerPoint
- Connection to course material
- Suggested modifications to methodology or additional testing
***Lab Notebook: All components of lab must be recorded into lab notebooks. Students will
also prepare group PowerPoint slides (2 total: 1 slide for each part of the lab) and a short
summary explaining results. Class PowerPoints will be upload on the AP website for students
to write conclusions regarding class data in notebooks. ***