In this exercise, students will investigate the effects of ecological factors on the growth of rapid-cycling brassica (Brassica rapa L.: RCB's; Wisconsin fast plants) seedlings in the field. Wisconsin Fast Plants belong to the Mustard family (Brassicaceae) and have been genetically bred to complete their life cycle in approximately 1 month. The students are asked to formulate a hypothesis and design an appropriate experiment to test their hypothesis. Possible variables that could be measured include growth (height, number of leaves, leaf area) or reproduction (number of flowers) with respect to treatments such as light, wind, herbivory, chemical or organic fertilizer, insecticides, or growth regulators (i.e., gibberellic acid spray, auxin paste). We also supply dwarf RCB's that lack genes for gibberellic acid production. These plants offer an additional test plant for the students to use.
Students spend two, 2-hour lab sessions on this project following a 20-30 minute introduction to the topic. During the introductory session (normally at the end of the preceding lab), the experiment is discussed and the students are encouraged to consider factors that affect seeding growth. Students should work in pairs and each group should formulate a hypothesis before the first field trip (lab 1). During the first field trip, the students should make observations about their study site, then design and implement their experiment (i.e., collect "before" data). During the second field trip, the students will collect response "after" data, which will be analyzed and used to write a scientific paper.
At the conclusion of this lab, students will be able to...
Equipment/ Logistics Required:
Summary of What is Due:
______________________________________________________________ Keyword Descriptors:
From this lab, students should submit the following:
Principal Ecological Question Addressed:
How do biotic and abiotic factors affect the growth of seedling plants?
Ecological Topic Keywords: plant ecology, Brassica, abiotic factors, biotic factors, seedling growth.
Science Methodological Skills Developed: experimental design, scientific writing, hypothesis testing, implementation of the scientific method, identify biotic and abiotic interactions affecting seedling growth.
Pedagogical Methods Used: cognitive skills, hands-on experience, problem-based learning