Chapter: 11th Botany : Chapter 15 : Plant Growth and Development
Arc auxanometer Experiment - Measurement of growth by direct method
Measurement of growth
Activity
Measurement of growth by direct method.
Step 1: Take ordinary scale.
Step 2: Measure ground stem up to the growing point of the plant.
Step 3: Use Indian ink and mark at regular intervals to measure
the length of root, stem, and girth of the trunk.
Experiment: 1. Arc auxanometer:
The increase in the length of the stem tip can easily be
measured by an arc auxanometer which consists of a small pulley to the axis of
which is attached a long pointer sliding over a graduated arc. A thread one end
of which is tied to the stem tip and another end to a weight passes over the
pulley tightly. As soon as the stem tip increases in length, the pulley moves
and the pointer slide over the graduated arc (Figure 15.8). The reading is
taken. The actual increase in the length of the stem is then calculated by
knowing the length of the pointer and the radius of the pulley. If the radius
of the pulley is 4 inches and the length of pointer 20 inches the actual growth
is measured as follows:
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