CROP PHYSIOLOGY Lecture Notes - Soil Salinity, Counterforce, Environmental Factor
Document Summary
Any environmental factor potentially unfavorable to plant is termed as stress. The effect of stress on plant condition is called strain. According to newton"s law of motion, a force is always accompanied by a counterforce, for an action there is always equal and opposite reaction. Stress is the action and whereas strain is the reaction: drought (water stress) Drought is defined as the deficiency of water severe enough to check the plant growth. Drought has been classified into two broad categories viz. , soil drought and atmospheric drought. Atmospheric drought occurs due to low atmospheric humidity, high wind velocity and high temperature which cause a plant to lose most of its water. Physiological changes occur due to drought: functioning of stomata. In general, stomata lose their function and may die, because wilting after certain limit denatures the starch in the guard cells and also in the mesophyll cells: carbohydrates metabolism in green leaves.
