Lab 5 - Allelopathy

The allelopathy lab is the lab of the semester that students will have to write a scientific lab report for. They must perform an experiment that determines the effects of a plant essential oil on the radish seeds Raphanus sativus. Since the lab report is a large portion of this course’s grade, it is important that the students utilize the full extent of the lab time. To help with this, a procedure summary was assigned prior to this lab for students to write about and understand the procedure of the lab. From this, they learned how to do the lab and also gained some familiarity with the subject before they even came into the lab. In the end, it worked quite well and students were able to complete the lab without much trouble. Most likely assigning procedure summaries in the future would be good for any other labs with a complex subject.

After the students turned in their summaries at the beginning of lab, the teaching assistant began his lecture on allelopathy. To help understanding of the subject, he used examples of allelopathic plants that students would know around Georgia. After the lecture, students proceeded directly into the lab portion, setting up petri dishes with radish seeds, water, and the essential oil treatment and reading information sheets of examples of allelochemicals. The teaching assistant helped students at the treatment station, while I helped students as I walked between the rest of the stations.

The lab went quite smoothly even though the subject was more complex than most other labs. The procedure summaries help jumpstart the lab, and students were able to create accurate hypotheses and predictions for their lab report. The only improvement capable is perhaps having two different essential oil treatments and comparing their effects on the seeds. This would further student’s knowledge of why plants produce allelochemicals and what they can do.

This is the essential oil used in this week’s lab, Mentha piperita (peppermint).

The control for experiment was this DI water.

These are the microcapillary tubes the students used to measure out the essential oil and DI water.

This is where the students looked at allelopathic specimens and read over allelochemical information sheets.