Plants lose water from their above-ground surfaces through transpiration. most of this water is lost from stomata, small openings in the leaves. excess water loss can have a negative effect on the growth, development, and reproduction of a plant. the first sign of this water loss is plant wilting, as water leaves the large central vacuole of the above-ground plant cells. severe water loss can be fatal. environmental factors have a major impact on the rate of plant transpiration.
consider the graph above, noting the rate of transpiration as atmospheric humidity increases. compare this process of osmosis of water from plant cells themselves.