NITROGEN ACQUISITION AND USE IN 3 PERENNIALS IN THE EARLY-STAGE OF PRIMARY SUCCESSION

1. Different patterns of nitrogen acquisition and use among species were important determinants of a successional sequence in the early stage of primary succession on Mt. Fuji. 2. The first colonizer, Polygonum cuspidatum, had the highest relative growth rate (RGR) under nitrogen-limited conditions, which arose from the higher plant nitrogen concentration (PNC) than the second colonizer, Miscanthus oligostachyus, and higher nitrogen productivity (NP) than the third colonizer, Aster ageratoides. 3. Polygonum cuspidatum allocated proportionately the least biomass to roots, while it had the highest specific root length and maintained a high absorption rate per unit root weight. NP of Polygonum cuspidatum was high because allocation of nitrogen to the leaves was high. 4. Although M. oligostachys allocated the least nitrogen to its leaves, it also had high NP because the nitrogen-use efficiency of its leaves was the highest. 5. Aster ageratoides allocated the least biomass to leaves and had the lowest NP of the three species. Large investment of biomass in roots, however, enabled this species to absorb much nitrogen, leading to high PNC under high nutrient conditions. 6. The relatively high RGR of Polygonum cuspidatum, even under nitrogen-limited conditions, is advantageous for colonization by this species while coping with disturbances due to the unstable ground surface of Mt. Fuji.