ABSTRACT
Abstract-The wettability of the inner (lumen) walls of the water-conducting capillaries in plants (tracheids and vessels) is an important parameter in both plant physiology and wood technology. However, although the macroscopic wettability of wood surfaces has received considerable attention, lumen wettability has not been studied in detail. Here measurements of the wettability of the lumen walls of tracheids of two species of Australian cypress (Callitris Vent.) are described. It is shown that wall roughness (the warty layer) significantly increases the wettability of the lumen wall, an observation which provides an appealing answer to the long-standing debate on the function of wall sculpturing in plant capillaries, and may provide clues for the biomimetic engineering of wettability in technological applications such as microfluidics. The results also demonstrate that lumen wettability is enhanced by the presence of hygroscopic sap residues, and is diminished by air-drying (aging).
