An auxanometer (Gr. '= "to grow" + ''metron''= "measure") is an apparatus for measuring increase of growth in
plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...
s.
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
A pulley is a wheel on an axle or shaft that is designed to support movement and change of direction of a taut cable or belt, or transfer of power between the shaft and cable or belt. In the case of a pulley supported by a frame or shell that ...
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
Magnitude may refer to:
Mathematics
*Euclidean vector, a quantity defined by both its magnitude and its direction
*Magnitude (mathematics), the relative size of an object
*Norm (mathematics), a term for the size or length of a vector
*Order of ...
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. 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 These simple types of auxanometer have been replaced by rotation sensors at the fulcrum point linked to dataloggers with a balancing beam attached to the growing tip/plant apex.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 Micrometer can mean:
* Micrometer (device), used for accurate measurements by means of a calibrated screw
* American spelling of micrometre
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; ...
, which allows measurement of growth in response to short-term changes in
atmospheric composition
Atmospheric chemistry is a branch of atmospheric science in which the chemistry of the Earth's atmosphere and that of other planets is studied. It is a multidisciplinary approach of research and draws on environmental chemistry, physics, meteorol ...
.
Auxanometers are used in laboratory,
the field, and the classroom.
See also
*
Crescograph
A crescograph is a device for measuring growth in plants. It was invented in the early 20th century by Sir Jagadish Chandra Bose.
The Bose crescograph uses a series of clockwork gears and a smoked glass plate to record the movement of the tip of ...
References
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Measuring instruments