Environmental Effects on Mitosis - Advanced Inquiry Laboratory Kit
Big Idea 3, Investigation 7

By: The Flinn Staff


Big Idea 3, Investigation 7, Science Practices 1, 5, 6, 7

Do different growing environments affect cell division in plants? Study the effects of biotic and abiotic factors on mitosis in onion root tips with this Flinn Advanced Inquiry Lab. The lab begins with a Baseline Activity studying cell division in two groups of onion root tips. First, students treat the root tips and create microscope slides to observe cell division. Then they perform a statistical analysis of percent mitosis in treated root tips versus a control group. This Baseline Activity provides a procedure and model for the Opportunities for Inquiry portion of the lab when students are tasked to develop a testable hypothesis and design an experiment that they can plan, discuss, evaluate, execute, and finally justify to their peers. Students are provided guiding questions such as, “In areas where there are very few plants growing, what biotic and abiotic factors may be affecting the rate of mitosis and the ability of plants to thrive?” and “What chemicals may be expected to increase or decrease the rate of mitosis in plants?” to help inspire the inquiry experiment.

Includes detailed teacher notes, reproducible student handouts, and enough materials for eight groups of students to complete the Baseline Activity and to prepare for the inquiry activity. Compound microscopes and onion root tips are required and available separately.

Red kidney bean lectin (Phytohemagglutinin) is used in the College Board lab. Lectin is a lyophilized powder that must be kept refrigerated. It is available from Flinn Scientific as Catalog No. L0114. The recommended concentration is 10 mg in 200 mL of deionized water. Once diluted, it must be stored in the refrigerator and is only active for a few days. Lectin increases mitosis in the roots, but is also hemolytic and must be used with appropriate personal protective equipment.