Which plants or plant tissues produce hydrogen cyanide?
Katrina Lustofin
(lustofin@uiuc.edu)
(ready to use)
ASK
Partner Projects
| GK-12 Teaching Fellowships |
Subject Areas
Grade Levels
Unit Keywords
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chemistry, plant defenses, hydrogen cyanide |
Rationale of the Unit
| Plants produce hydrogen cyanide gas as a defense against herbivory. We used a qualitatitive measure to determine which tissues/plants do this as a part of understanding the difference between qualitative and quantitative measures. We also tied in balancing equations, by examining the reactions occuring. |
Background and Resources
The following articles were used to develop the technique:
Brinker, A.M. and Seigler, D.S. 1989. Methods for the detection and quantitative determination of cyanide in plant materials. Phytochemical Bulletin 21(2): 24-31.
Feigl, F. and Anger, V. 1966. Replacement of benzidine by copper ethylacetoacetate and tetra base as spot-test reagent for hydrogen cyanide and cyanogen. Analyst, 91: 282-284.
Many websites are available that explain cyanogenesis by plants, including:
http://www.npsot.org/features/default.htm
http://extoxnet.orst.edu/faqs/natural/cya.htm
Several veterinary medicine sites list cyanogenic plants and potential hazards to livestock, including:
http://cal.vet.upenn.edu/poison/plants/ppcyano.htm
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Activities and Open-ended problems
Dialogues, Discussions, and Presentations
| Discussion topics include the differences between qualitative and quantitative measures, how to make this technique into a semi-quantitative measure. Have students balance the equation for the reaction of the Feigl-Anger strips. Talk about how to avoid poisoning, especially since cassava is such an important food plant. |
Assessment, Related Questions, and Story of the Unit
| I thought our students did a good job with this experiment. They enjoyed choosing different plant tissues to try and seeing how the strips changed color. We had a good discussion on the topics above. |
Credits & Acknowledgements
| Susan Camasta, GK12 program |
Uploaded Files:
Chemicalequationslab.doc
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