Question

Explain the three phases of growth.

Answer 1

Phases of growth

There are three phases of growth, 

1. Formative phase, 

2. Elongation phase and 

3. Maturation phase

1. Formative phase: Growth in this phase occurs in meristematic cells of the shoot and root tips. These cells are small in size, have dense protoplasm, large nucleus, and small vacuoles. Cells divide continuously by mitotic cell division. Some cells retain the capability of cell division while other cells enter the next phase of growth.
2. Elongation Phase: Newly formed daughter cells are pushed out of the meristematic zone
   and increase the volume. It requires auxin and food supply, deposition of new cell wall materials (intussusception), the addition of protoplasm, and development of central vacuole take place.
3. Maturation Phase: During this stage cells attain mature form and size. Thickening and differentiation take place. After differentiation, the cells do not grow further.