Changes in resource allocation among vegetative organs during the clonal growth of Polygonatum humile (Liliaceae) grown in a temperate forest gap

Background: The aim of this study was to examine the resource allocation among the organs and the leaf morphology of Polygonatum humile. The data were collected from June 2014 to May 2015 in a natural P. humile stand of a temperate forest gap. Results: The dry weight of new rhizome (R0) sharply decreased to the time of new shoot sprouting in next year and was constant for 2 ~ 3 years. However, dry weight of root on R0 increased to the end of growth season and, thereafter, decreased slowly along the time elapsed. The correlation coefficients between the rhizome and the leaf sizes were 0.5 for the last year’s rhizome (R1) and 0.6 for R0 and were significant at 0.1% level for R0. The increase of one leaf a plant led to increase of the total leaf area, total leaf weight, and stem length. Moreover, the organ sizes’ differences between two plants of the one leaf difference were almost significant at 1% level. In 11-leaf plant, the leaf length/width ratio and specific lea area increased to the second, relative leaf area to the fourth and relative leaf dry weight to the fifth, and thereafter, decreased to the last leaf. The differences in the values of these four parameters between two leaves on a stem were almost significant at 5% level. Conclusion: P. humile examined showed the close relationships between the last year’s rhizome or this year’s one and the shoot system (leaf and stem) sizes. The leaf number a shoot greatly influenced specific leaf area. P. humile’s leaf might showed diverse morphology with leaf rank on a stem in a forest gap environment.