ECOPHYSIOLOGICAL CHARACTERIZATION OF C. SATIVA MILL.

The aim of this work is to make an ecophysiological characterization of European chestnut, with respect to irradiation, temperature and water relations. European chestnut is a dim-light species, which attains 75% of maximal photosynthesis when irradiation is 1000 μmol.m^-2.s^-1. The results also show that this is a typical species of temperate climates, since optimal temperature for photosynthesis was found at 24°C, a factor which has a strong influence on water use efficiency and transpiration within the a range of 10–40°C. Maximal CO₂ fixation was 10 μmol.m^-2.s^-1, and at 24°C transpiration rate was around 4.5 mmol. m^-2.s^-1. Portuguese cultivars showed a range of optimal temperatures between 22 and 29°C.