Altitudinal trends in photosynthetic rate and leaf characteristics of Miscanthus populations from central Taiwan

Leaf photosynthetic rate and leaf characteristics including chlorophyll con tent, leaf width, leaf mass per area (LMA), stomatal density and the dimens ions of guard cells were measured in C-4 Miscanthus spp. growing along an a ltitudinal gradient from 390 to 2700 m in central Taiwan. The main objectiv e of this study was to understand if morphological and physiological variat ion occur in leaves of the C-4 plants growing along the altitudinal gradien t. Measurements were taken during the growing season, May, July and Septemb er, of 1997. Photosynthetic rate, leaf width and guard cell dimensions decr eased while LMA and stomatal density increased with altitude. The pattern o f continuous variation in the analysed parameters suggests that it is relat ed to some underlying environmental factors (mainly air temperature and CO2 concentration) associated with changing altitude.