A COMPARATIVE-STUDY OF MISCANTHUS-FLORIDULUS (LABILL) WARB AND MISCANTHUS-TRANSMORRISONENSIS HAYATA - PHOTOSYNTHETIC GAS-EXCHANGE, LEAF CHARACTERISTICS AND GROWTH IN CONTROLLED ENVIRONMENTS

The relationship between temperature and the distribution of Miscanthu s floridulus (Labill) Warb and M. transmorrisonensis Hayata along alti tudinal gradients in central Taiwan was examined. Responses of biomass accumulation, leaf characteristics and photosynthetic gas exchange to growth temperature (from 10 to 30 degrees C) of M. floridulus from an altitude of 390 m and of M. transmorrisonensis from 2700 m were deter mined. There were differences between the two species in above-ground biomass, CO2 uptake characteristics and leaf chlorophyll contents in r esponse to growth temperature. The optimal temperatures for biomass ac cumulation were 30/25 (day/night temperature) and 25/20 degrees C for M. floridulus and M. transmorrisonensis, respectively. Light saturated photosynthetic rates (A(max)) were largest in plants grown at the opt imal temperature. Growth at 15/10 and 10/10 degrees C compared to the optima reduced accumulated biomass, leaf chlorophyll content and photo synthetic rate in both species with a greater reduction in M. floridul us than in M. transmorrisonensis. We concluded that growth of M. flori dulus at high altitude is limited by an inability to grow at temperatu res lower than 15 degrees C, while M. transmorrisonensis is able to gr ow in chilling temperatures at higher altitudes. (C) 1998 Annals of Bo tany Company.