Abstract:

To select suitable tree species for riparian revegetation in the Three Gorges Reservoir Area, three different kinds of water treatment simulating the riparian soil water changes were applied, including control (CK), continuous flooding (CF), and periodic flooding-drought (PF). Photosynthesis, biomass, growth and other related physio-ecological characteristics of Pinus elliottii seedlings were examined in this research. Results showed that water treatment could significantly influence photosynthesis, biomass and growth of P. elliottii seedlings. Net photosynthetic rate (P_n) and stomatal conductance (G_s) in CF and PF were significantly lower than those in CK, with a significant higher intercellular carbon dioxide concentration (C_i) in the two treatments than in CK. With extension of the treatment duration, there was a continuous increase in total biomass, root biomass, stem biomass, leaf biomass, plant height and base diameter of both CF and PF. In terms of the overall average value throughout the experimental period, no significant difference was found in total biomass, root biomass, stem biomass, plant height and base diameter between CF and PF; however, the parameters in both CF and PF were significantly lower than that of CK. The results verified that P. elliottii seedling was capable to tolerate water and drought stresses, and could be a candidate species for establishing riparian shelterbelt in the Three Gorges Reservoir Area.

Key words: water stress, Pinus elliottii seedlings, photosynthesis, growth characteristics, the Three Gorges Reservoir Area