In case of an arc-auxanometer (see picture), there is a wire fixed with the plant apex on one end and a dead-weight on the other. It passes over a pulley which has a pointer attached to it. When the plant's height increases, the pulley rotates and the pointer moves on a circular scale to directly give the magnitude of growth. The "rate of growth" is a derived measurement obtained by dividing the length of growth measured by the auxanometer, by the time said measurement took.
Sensitive auxanometers allow measurement of growth as small as a micrometer, which allows measurement of growth in response to short-term changes in atmospheric composition. Auxanometers are used in laboratory, the field, and the classroom. It is also called an arc-indicator.
- Chisholm, Hugh, ed. (1911). Encyclopædia Britannica. 3 (11th ed.). Cambridge University Press. p. 50. .
- Beach, Chandler B., ed. (1914). The New Student's Reference Work. Chicago: F. E. Compton and Co. .
- Bovie, W. T. (1912), "A Precision Auxanometer", Botanical Gazette, 53 (6): 504, doi:10.1086/330848
- Ranson, S. L.; Harrison, A. (1955), "Experiments on Growth in Length of Plant Organs", Journal of Experimental Botany, 6: 75, doi:10.1093/jxb/6.1.75
- Gallagher, J. N.; Biscoe, P. V.; Saffell, R. A. (1976), "A Sensitive Auxanometer for Field Use", Journal of Experimental Botany, 27 (4): 704, doi:10.1093/jxb/27.4.704
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