Abstract:

Acacia mangium is a fast growing tropical tree species with significant economic and ecological values. The diurnal variations of photosynthesis and daily-integrated photosynthetic CO2 assimilation over whole photoperiods of A. mangium phyllode were investigated. The results showed that the photosynthetic CO2 uptake of A. mangium phyllode exhibited a 14.5% decrease during midday. The PSII of the A. mangium phyllode was tolerant to high Photosynthetic photon flux density (PPFD) levels and high temperatures. The integrated daily carbon gain and nocturnal carbon loss of A. mangium phyllode was 502 mmol CO2·m-2·day-1 and 54 mmol CO2·m-2·day-1, respectively. All of these physiological traits allow A. mangium to take advantage of the high PPFD environment in the tropics and help this plant to realize rapid growth.