- The 1st age class rhizome emerges at mid of growing season.
- At this age, the biomass of the age class is maximum.
- Among them, 35~age group was the maximum of death age class, constituting 29.1% of constitution of causes of death.
- The dry matter storage and water soluble sugar content in older age class rhizomes increased with year.
- The dry matter storage and water soluble sugar content in P. communis rhizomes increased in quadratic with increasing age class.
- The capacity for contribution of the modules of every age class of population was 2nd > 1st >3rd > 4th in terms of dry matter production in the milk stage.