Role and effects of winter buds and rhizome morphology on the survival and growth of common reed (Phragmites australis)

To confirm the role of winter buds and rhizome morphology on the winter survival and subsequent growth of common reed (Phragmites australis), rhizome fragments of varying sizes with and without winter buds from three different P. australis populations were transplanted to small pots in a greenhouse and wintered by exposing them to a dry atmospheric condition. Survival ratios of the rhizome fragments with winter buds were much greater than those without winter buds regardless of population type, supporting that winter buds play a role as the insulator of rhizome fragments from dry atmosphere during winter season. Most growth characteristics of surviving P. australis from the rhizome fragments were similar to those in natural wetlands, indicating preserved growth characteristics through the rhizomes, which is an asexual organ. The average number of rhizome fragment nodes showed negative relationships with the number of blades per culm (P < .05) and basal culm diameter (P < .05) of surviving P. australis. In contrast, the diameter of planted rhizome fragments had significant positive relationships with the final shoot height (P < .05), above-ground dry weight (P < .05), root DW (P < .01), and total DW (P < .05). Rhizome volume also showed a similar correlation with the rhizome diameter. Thicker and larger rhizome fragments particularly with winter buds, indicating the young age of rhizome, seemed likely to guarantee greater survival and higher subsequent shoot growth and biomass production as well.