Figure 3. Water transport in inner pine cones.

(a-d) Water absorption in the inner pine cones was observed by dipping their bottom into water. The inner pine cones consist of three layers and they draw water up independently. White arrows represent the direction of the spreading water. ‘B’, ‘F’ and ‘I’ represents bract scales, fibers and innermost lignified structure, respectively. (e) Temporal variations of wet surface areas of the three layers are depicted as a graph. The time of fully damping is different each other. (f-g) 3D inner structures of the bract scales (f) and fibers (g) were observed using multi-photon microscopy. Their different micro-structures seemed to induce independent water uptake. Scale bars in (a-d) and (f–g) indicate 5 mm and 200 μm, respectively.