Education & Outreach
Helm, Kenneth W. .
Exploring metabolism in pea seedlings and potato tuber tissues using a simple respirometer.
The remarkable changes in respiration that occur during seed germination and seedling growth serve as a valuable tool for illustrating the dynamic nature of carbon metabolism in plants, and the more general concepts important in understanding energy metabolism in all aerobic organisms. Using a simple respirometer of the type often employed in introductory biology exercises students can, for example, discover how respiration increases with imbibition time, show how respiration in shoots and roots is dependent on the presence of the cotyledons, and learn about tissue-dependent differences in metabolic rates. In addition, the ability of Pisum sativum seedlings to maintain respiration over a wide temperature range is a powerful demonstration of plants’ ability to withstand environmental stress. Experiments of a more biochemical nature can be performed using potato tuber slices. Metabolic stimulation from “aging” of tuber tissue, and the effects of uncouplers and inhibitors like cyanide are readily detectable with this method. To measure respiration, samples (1-5 gm) were placed in sealed tubes fitted with 1 ml pipettes. CO2 was absorbedÂ by small amounts of Ascarite, and high humidity was maintained with moistened paper towels. Oxygen uptake, and the accompanying reduction of atmospheric volume in the tubes, was monitored by measuring the position of water droplets in the pipettes. Metabolic rates as low as 0.5 ÎĽl O2 min-1gm fw-1 were easily detectable. Measuring oxygen uptake with these respirometers, as opposed to more complicated methods, enables students to design and perform informative and interesting experiments independently.
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1 - Siena College, Biology, Loudonville, NY, 12211, USA
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM