Growth and development, factors affecting growth and development

Growth and development, factors affecting growth and development

1. Growth and development, its definition, growth curve and
factors affecting growth and development

3. Definition of growth:
Growth is an irreversible change in the size of a cell,
organ or whole organism.
Commonly growth is the increase in the amount of
living material (protoplasm) which leads to an increase
in cell size and ultimately cell division.
Development :
It is the orderly and progressive change from seed
germination through juvenility, maturity, flowering and
fruiting.

6. Growth Curve

7. Growth curve:
All plants pass through various stage of growth.
Growth is best expressed by means of a curve
plotted against time.
Growth curves are helpful in understanding the
general pattern of growth.
The S-shaped or sigmoid curve is typical of growth
pattern of individual organ of a whole plant and of
population of plants.
In consist five distinct phases

8. The rate of growth of a plant or plant part is not always the same during its
life span. Sometimes it is slow and at other times rapid.
If we plot the increase in cell number (growth rate) against time, a typical S-
shaped curve is obtained.
This is called growth curve or sigmoid growth curve.
This curve has three phases of growth.
1. Lag Phase – This is the initial phase of growth when the rate of growth is
very slow.
2. Log Phase – It shows rapid growth and is maximum during the entire life
span.
3. Senescence Phase - Senescence
 is the final stage of plant development.
4. Stationary Phase – Here the rate of growth starts decreasing and finally it
stops.
5. Death Phase -

9. The total time period during which
the fastest growth of the organ or
organism occurs is called grand
period of growth.