Conditions for Plant Growth

The growth rate of plants is determined by various external and internal factors.

A. EXTERNAL FACTORS

Temperature

Temperature plays a crucial role in the growth of plants. A suitable temperature ranging from 25 °C to 30°C is necessary for maximum growth. However, the growth rate increases with a rise in temperature and decreases with a decrease in temperature. At high temperatures, i.e. 35 °C to 40 °C, the rate of growth stops, and the plant may die.

Light

Light influences plant growth in three ways: intensity, quality, and duration. The intensity of light affects the number of cell divisions, whereas red light favors cell elongation, and blue light increases cell division. The duration of light affects the growth of vegetative and reproductive structures, and it also plays a role in inducing or suppressing flowering.

Oxygen

Metabolic activities and growth cannot occur without oxygen. However, a very high supply of oxygen inhibits growth.

Carbon dioxide

Carbon dioxide (CO₂) is necessary for photosynthesis, but its high concentration can retard plant growth.

 

B. INTERNAL FACTORS

Hormones

Indole acetic acid (auxins) is a hormone that causes elongation of cells.

Water

Water is crucial for the elongation of cells, and the cell elongates by absorbing water.

Nutrition

Nutrients are essential for the growth of plants, and their deficiency can retard plant growth.

Vitamins

Vitamins are synthesized in plants in the presence of light. Thus, if the plant is grown in the dark, the growth of the plant body ceases.

 

External and internal factors both influence the growth rate of plants, and understanding these factors can help optimize plant growth for various purposes.