Respiration for maintenance and growth in Reynoutria japonica ecotypes from different altitudes on Mt Fuji

Respiration for maintenance and growth of Reynoutria japonica ecotypes from altitudes of 700 and 2420 m on Mt Fuji were measured in two controlled thermal conditions. The maintenance respiration of the high-altitude ecotype at both 15 and 25°C was significantly (1.7-fold) higher than that of the low-altitude ecotype, whereas growth respiration was independent of both ecotype and temperature. The temperature coefficient (Q₁₀) of the maintenance respiration was about 1.9 in both ecotypes. The results show that there is ecotypic differentiation in the performance of maintenance respiration. It is suggested that the high maintenance respiration of the high-altitude R. japonica ecotype is advantageous in severe upland environments but disadvantageous in a warm lowland climate in terms of carbon economy.