Auxanometer

Arc Auxanometer

An auxanometer (Gr. auxain= "to grow" + metron= "measure") is an apparatus for measuring increase of growth in plants.^[1]

In case of an arc-auxanometer (see picture), there is a thin cord fixed to the plant apex on one end and a dead-weight on the other with a pointer indicating against an arc scale. In some forms 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.^[2] 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. It is also called an arc-indicator. These simple types of auxanometer have been replaced by rotation sensors at the fulcrum point linked to dataloggers with a balancing beam attached to the growing tip/plant apex.

Sensitive auxanometers allow measurement of growth as small as a micrometer,^[3] which allows measurement of growth in response to short-term changes in atmospheric composition.^[4] Auxanometers are used in laboratory,^[4] the field,^[5] and the classroom.^[6]

See also

• Crescograph

References

1. Chisholm, Hugh, ed. (1911). "Auxanometer" . Encyclopædia Britannica. Vol. 3 (11th ed.). Cambridge University Press. p. 50.
2. Beach, Chandler B., ed. (1914). "Auxanometer" . The New Student's Reference Work . Chicago: F. E. Compton and Co.
3. Bovie, W. T. (1912), "A Precision Auxanometer", Botanical Gazette, 53 (6): 504–509, doi:10.1086/330848
4. Ranson, S. L.; Harrison, A. (1955), "Experiments on Growth in Length of Plant Organs", Journal of Experimental Botany, 6: 75–79, doi:10.1093/jxb/6.1.75
5. 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
6. W. T. Bovie; W. T. Bovie (1915), "A Simplified Precision Auxanometer", American Journal of Botany, 2 (2): 95–99, doi:10.2307/2435215, JSTOR 2435215