Question

A typical growth curve in plants is

• A. linear
• B. zig-zag shaped
• C. parabolic
• D. sigmoid

Answer 1

The correct option is D sigmoid


Growth curve is the graphical representation of the total growth of an organism (here plants) that is plotted against a particular time interval.

An S- shaped or sigmoid curve is obtained upon plotting the total growth of a plant against a particular time interval. It consists of 4 phases- lag phase, log or exponential phase, stationary phase (steady growth phase in organs or organisms exhibiting indefinite growth) and diminishing growth phase or decline phase.

During the lag phase, growth is slow, rapid growth is observed during the log or exponential phase, slow again during the diminishing growth phase. During the stationary phase, growth stops due to limited supply of nutrients and deposition of toxic waste materials. A sigmoid curve is characteristic to an organism growing in a natural environment. The equation that represents exponential growth is
$W_1=W_0{e}^{rt}$
$W_1$ = final size attained (weight, height, number etc.)
$W_0$ = initial size to begin with
e= base of natural logarithms
r= relative growth rate
t= time of growth