Salt tolerance of the African haplotype of Phragmites australis (Poaceae)

摘要

We determined the effect of salinity on growth of P. australis in glasshouse and field experiments. In the glasshouse, plants were subjected to 0, 10, 20, 30, 40 and 50 sea water for 32 weeks. Plant height, biomass and photosynthesis decreased with increase in salinity from 0 to 50 sea water. In the 50 sea water treatment, plant height decreased by 44, total biomass by 62, above-ground biomass by 61 and below-ground biomass by 62. CO2 exchange ranged from 9.07 mu mol m(-2) s(-1) in the control to 1.49 mu mol m(-2) s(-1) in the 50 sea water treatment. In the 50 sea water treatment, leaf conductance, CO2 exchange and transpiration decreased by 81, 84 and 78, respectively, while quantum yield and electron transport rate decreased by 34, and 20, respectively. In the field study, leaf conductance, CO2 exchange and transpiration were higher in the non-saline site and lower in the saline site by 50, 46 and 43, respectively. Quantum yield and electron transport rate were higher in the non-saline site and reduced in the saline site by 15 and 11, respectively. The results suggest that although P. australis is tolerant of increasing salinity, growth and productivity are reduced significantly.