Growth is affected by the factor which affect the activity of protoplasm. It is affected by a large number of factors both environmental and physiological. Physiologogical factors such as absorption of water, minerals, photosynthesis, respiration etc, and environmental factors including climatic and edaphic both. The effect on these factors on one region of plant are also transmitted to other region of the plant.
Since growth is a resultant of many metabolic processes, it is affected by many external and internal factors, which are as follows,
(i) External factors
(a) Light : Light affects variously e.g., light intensity, quality and periodicity.
