Plant growing in N poor habitats usually exhibit some particular traits. Miscanthus condensatus, a C4 plant, with characteristics of fast growth and high biomass, is the most dominant pioneer species on the volcanically devastated site in Miyake volcano.
To understand the successional mechanism based on species functional traits and changing habitat condition in volcanically devastated site, this study focuses on the photosynthetic properties of M. condensatus, on different developmental stages in volcanically devastated sites.
Various habitat environments (bare land, grass land and shrub land) with significant different light and soil nitrogen content were selected. At each site, five growing well M. condensatus individuals were selected. Saturated photosynthetic rate (Amax) and leaf nitrogen content were obtained to determine the photosynthetic nitrogen use efficienc(PNUE).
In the bare land, leaf N was significantly lower than in grass land and shrub land and showed a downward trend from May to August. Amax in nitrogen-poor site (bare land) significantly lower than grass land and shrub land. We also found that in the nitrogen-poor site, the photosynthetic rate showed relative high seasonal fluctuations. It may be due to that the high nutrient retranslocation capacity as adaptation for growing in bare land. In late summer, the M.condensatus at bare land may reallocate more nitrogen to root for next year growth. In the most devastated site with thick un-weathered volcanic ash, we found that that M. condensatus had highest PNUE value. It seems to be adaptive to the extremely low soil N conditions of new volcanic ash.