3.4 The pathways of leaf water uptake in Capparis
odoratissima
Dye loading onto the abaxial surface resulted in uptake that we believe
was mediated by the central anchoring area of the peltate hairs (Figure
6a) due to the intense staining that remained in the thick walls of this
central area of the peltate hairs after dye absorption (Figure 6b,
Videos S2-S3). Fluorescence was further observed in the mesophyll of the
leaves when dye was loaded onto either the adaxial or the abaxial
surface, pointing to the dual role of the leaf surfaces in water uptake.
Strikingly, the structures which retained the dye the most were the
walls of the idioblasts, compared with a lack of fluorescence in these
structures at the areas of the leaf without dye, which were used as
negative controls (Figure 6c-d). The lumen of the idioblasts also became
filled with the fluorescent dye, including the crenations (Figure 6e-f),
revealing them as the bridges of water uptake from the leaf surface to
the mesophyll.