The greater the difference in humidity the faster water will move. When the stomata are open water vapor rushes out. As the vapor moves out, a cloud of high humidity is formed around the stomate. This cloud of humidity helps slow down transpiration and cool the leaf. If air movement blows the humid cloud away transpiration will increase as the stomata keep opening to balance the humidity.
Plant nutrition refers to the needs and uses of the basic chemical elements in the plant.
Fertilization is the term used when these materials are supplied to the environment around the plant. A lot must happen before a chemical element supplied in a fertilizer can be taken up and used by the plant. Plants need 18 elements for normal growth. Carbon, hydrogen, and oxygen are found in air and water. Nitrogen, phosphorus, potassium, magnesium, calcium, and sulfur are found in the soil.