Respiration is a key factor that determines the productivity of a plant. Compared to trees, surprisingly little is known about the respiratory characteristics of bamboo, especially culm respiration. Since bamboo culms are hollow and have no radial growth, factors used to explain tree stem respiration such as diameter and stem growth rate may not be applicable. The objectives of this study were to examine seasonal and age related variation in culm respiration of Moso bamboo and to find morphological and anatomical factors that can explain this variation. We measured the respiration rates of current year, 2, 3, and above 4 year-old culms, and examined their morphology, wood density, and anatomical structure.

All culms showed seasonal variation, with current year culms having substantially higher respiration rates than other age culms throughout the year. A considerable increase in wood density in half a year was seen only in current year culms, and was related to changes in cell wall thickness of the culm tissue. Our results suggest that development of cell walls in the culm tissue cause the higher respiration rates for current year culms.