Abstract
The rhizomes of Polygonatum macranthum (Maxim.) Koidz. undergo a period of endodormancy after the formation of new rhizomes in summer. The decrease in the dormancy level with time and the chilling requirements for breaking dormancy are examined in this paper. The rhizome dormancy was deepest in early July or earlier, and after this the level of dormancy decreased gradually with time. After late November the decrease was more progressive, as a result of exposure to low outdoor temperatures. The rhizome dormancy was almost broken by late February to late March. The optimum temperature range, for sprouting of rhizomes almost released from dormancy, was 25 to 30°C. Chilling was effective in breaking the dormancy of rhizomes when the rhizomes were dug in late August or later. The rhizomes dug in late September required a 120-day period of chilling at 5°C to break dormancy completely, whereas a 90-day period of chilling at 5°C was enough to completely break the dormancy of those dug in late October. When connected rhizomes with many buds were planted, half the number of buds did not expand. However, all buds expanded when divided rhizomes with only one bud were planted.
