Minerals dissolved in soil water move into plant roots and then to the vascular system, more specifically the xylem, for transport throughout the plant. There they combine with proteins to form enzymes that control the biochemical reactions essential to plant health and growth. In the simplest terms, the driving mechanism for the transport of water through a plant is transpiration or the evaporation of water from plant leaves. Tiny pores or stomates in leaves control the amount of transpiration. Stomates open and close in response to water availability as well as other internal and external factors.
Transpiration occurs as long as stomates are open.
Transpiration sets up a negative pressure that drives the movement of water from the soil to the plant and through the plant via the xylem. The movement of water from soil to roots to xylem to leaves to air can be viewed as a continuum. Interruption at any stage of the continuum stops or reduces the flow of water, leading to wilting of leaves. Drought effects on plants Drought conditions, or more specifically, soil water deficits, can influence the normal physiology and growth of plants in many ways. For example, when a soil water deficit exists, the result may be an increase of solute concentration outside the roots compared to the internal environment of the root.