What is plant growth and development?
Plant growth and development
It is an irreversible permanent increase in size of an organ or its parts or even of an individual cell.
• It is regarded as one of the most fundamental and conspicuous characteristics of a living being.
• It is accompanied by metabolic processes that occur at the expense of energy. For More Biology Doubts visit main page of Physics Wallah.
This is obtained by plotting growth rate of a plant against time. Growth curve resembles the shape of ‘S’ and so it is named as sigmoid curve.
The growth curve consists of three phases of growth. They are
(i) Lag phase
This is the first phase of growth. In this period, growth is slow but steady. Since new cells are formed from meristematic zones, this phase is also called formative phase.
(ii) Log phase
This is the second phase of growth. This is a period of maximum growth. In this phase, plant shows rapid increase in its height. It is also called logarithmic phase or exponential phase.
(iii) Senscent phase
This is the third phase during which plant exhibits declining growth activity. This phase corresponds to maturity of cells. The log phase is followed by senescent phase.