Abstract
In this study, the authors monitored the size of Sasa veitchii (Carriere) Rehder var. hirsuta (Koidzumi) S. Suzuki seedlings grown under various light conditions (five experimental plots with relative solar radiation levels of approx. 90, 73, 55, 28 and 15 %) in order to clarify the relationship between light conditions and growth. The results showed that the growth rate of above-ground and underground organs was at its highest with a relative solar radiation level of around 55 %, and that the rate diminished below and above this level. In a secondary forest (a natural habitat of the species), the relative solar radiation in a canopy gap (44-56 %) was significantly greater than that at a closed-canopy site (16-32 %). The results obtained suggest that light conditions influence the growth of above-ground and underground organs for Sasa veitchii var. hirsuta seedlings, and that sites with favorable light conditions, such as canopy gaps, are advantageous for seedling growth in natural habitats. Rhizome emergence in one-year seedlings and rhizome expansion in two-and three-year seedlings were observed in individual experimental plots. The results obtained here suggest that the growth pattern of Sasa veitchii var. hirsuta seedlings involves vigorous rhizome extension from the initial stage of regeneration regardless of light conditions.
