Question

Typical growth curve in plants is
A. Stair- steps shaped
B. Parabolic
C. Sigmoid
D. Linear

Answer 1

Hint: This curve is also known as the S-shaped curve. The rate of growth of a plant or part of a plant is not always the same during its lifespan.

Complete answer:
 A growth curve is a graphical representation of how a particular quantity increases over the time. It is a sigmoid curve or also called as S-Curve obtained when a graph is plotted between growth versus time as shown in the figure. This curve mainly shows 4 phases of growth:
Initial slow growth (Lag phase): increases slowly initially.
A) The rate period of growth (Log phase or exponential phase): maximum growth is seen in a short period of time.
B) Diminishing phase: growth will be slow.
C) Stationary or steady phase: finally, growth stops.

Thus, the correct answer is option C i.e., Sigmoid curve.

Additional information:
1) Growth may be defined as an irreversible permanent increase in size, volume or mass of a cell or organ or whole organism accompanied by an increase in dry weight. Types of growth:
2) Primary and secondary growth -: shoot and root apex increase the length of the plant body and this is called primary growth. The secondary meristem increases the diameter of the plant body and this is called secondary growth.
3) Unlimited growth: shoot and root grow continuously throughout the life of the plant.
4) Limited growth: leaves, fruits etc. stops growing after attaining a certain size.
5) Vegetative growth: earlier growth of plants without flowers.
6) Reproductive growth: after vegetative growth, plants produce flowers.

Note: In plants seed germinates and develops into seeding and later it assumes the shape of an adult plant. Plants show indefinite and diffuse growth while animals show fixed and uniform growth.