Water distribution on the transverse surface of the stems.

Cryo-SEM images of the transverse surfaces of the stems, (upper panels) taken on the first day of the first drought treatment and those (lower panels) taken on the second day of the recovery (irrigation) period, in D. lepidotum (A, B), H. glaber (C, D), S. mertensiana (E, F), and B. javanica (G, H). Vessels with dark lumen indicate cavitated and vessels with light gray lumen indicate being filled with water. Note that each sapling had a nearly zero water potential when it was frozen in liquid nitrogen. Scale bars indicate 200μm.