C D
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).