Can anyone give me a basic background on transpiration?

Answer 1

TRANSPIRATION-COHESION-ADHESION THEORY:
a). water leaves leaf through stomata.
b). this water loss is replaced by evaporation from mesophyll cells, lowering their water potential, causing them to take water from neighboring cells.
c). Process continues back to the tracheids causing water up take from the xylem sap.
d). Water goes from tracheids to air following a water potential gradient.
e). Cohesion and adhesion of water. H bonds of water, hydrophilic walls of xylem and small diameter of xylem aid in the movement of water up the tube.
f). This pull decreases water pressure in the xylem causing the roots to take water from the soil.

Answer 2

Transpiration is the evaporation of water into the atmosphere from the leaves and stems of plants. Plants absorb soilwater through their roots and this water can originate from deep in the soil. (For example, corn plants have roots that are 2.5 meters deep, while some desert plants have roots that extend 20 meters into the ground). Plants pump the water up from the soil to deliver nutrients to their leaves. This pumping is driven by the evaporation of water through small pores called "stomates", which are found on the undersides of leaves. Transpiration accounts for approximately 10% of all evaporating water.