Transpiration serves to evaporatively cool grass as the escaping water vapor carries away heat energy. Unequaled Hollow blade design by GST is something you will never find elsewhere. Hollow blade technology mimics the same process which helps to keep moisture inside stems longer and therefore to diminish the temperature of a lawn. In plants, leaf surfaces are dotted with stomata (openings, or holes) bordered by guard cells that open and close the pore. The hollow veil in the center of the grass leaves makes up not only for genuinely brilliant lifelike look of grass, but supports its superior to keep temperature of a lawn stable and cool in hot climates. Transpiration which cools plants occurs through the stomatal apertures.