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FIGURE 8. Simplified model of water balance in the leaves ofCapparis odoratissima . (a) In the absence of high humidity of the surrounding atmosphere, the water potential of the leaves is higher than the surrounding environment, thus there is a net loss of water (blue arrows). (b). The opposite situation happens with submerged leaves, which have lower water potentials than the environment, thus gaining water (blue arrows) through the lumen of the continuum peltate hairs-idoblasts. (c) When water condenses in the upper surface, the inner leaf potential is lower than this surface, thus allowing water to enter through the lumen of the idioblasts (blue arrow), while water losses from the lower surface (assuming a ´dry´environment) may equal water gains (dotted arrows). (d) When water condenses in the lower surface, water enters through the lumen of the peltate hairs and the idioblasts (thick blue arrow), but cuticular water loss through the upper leaf surface (assuming a ´dry´environment) appears to be lower than water entrance (thin blue arrow).