Figure 5.

Cryo-SEM photographs of B. platyphylla var. japonica in winter. A, Transverse surface of current-year xylem in November. Most vessels were filled with water, whereas almost all fiber lumina were empty. B, Current-year xylem in November. Vessels (v) were filled with water. C, Transverse surface of previous-year xylem in January. Some vessels were filled with water but others contained no water. D, Previous-year xylem in January. Both water-filled fibers (large arrow) and empty fibers (small arrow) were present. E, Transverse surface of previous-year xylem in February. Most vessels were empty. F, Previous-year xylem in February. Most vessels and fibers contained no water.