Photosynthetic characteristics of three typical trees for vegetation restoration in dry season of dry-hot valley.
Objective: This paper aimed to explore the photosynthetic characteristics of three typical afforestation tree species in dry-hot valley. Method: LI-6400 was applied to measure the main photosynthetic parameters against photosynthetically active radiation (PAR) of Moringa oleifera, Tamarindus indica and Leucaena leucocephala, and the transpiration and water use efficiency (WUE) were also discussed. Result: The Pn and Gs of 3 species showed different responses to PAR variations. Under weak light zone (PAR <500 µmol.m-2 s-1), the Pn of three tree species increased rapidly with PAR, but the increase rates were relatively lower for T. indica and higher for M. oleifera. Generally, the Pn of three species were in order of M. oleifera > L. leucocephala > T. indica. M. oleifera, and L. leucocephala had higher light saturation point, while L. leucocephala and T. indica possessed lower light compensation points. The apparent quantum efficiency (AQY) of 3 species were generally within the normal range, but the AQY of M. oleifera and L. leucocephala were significantly higher than that of T. indica (P<0.05). The transpiration rate of T. indica was significantly lower than that of M. oleifera and L. leucocephala (P<0.05), and the WUE of 3 species were in order of M. oleifera > T. indica > L. leucocephala. Conclusion: With high transpiration, low water use efficiency and potential harm characteristic of invasive plant, L. leucocephala should be carefully selected as vegetation restoration specie in the dry-hot valleys.