Biomass production and mineral nutrition of Suaeda fruticosa growth on high salinity medium in connection with nutrient availability

Suaeda fruticosa is a frequent halophyte in semi-arid, arid and desertic zones of Tunisia. This Chenopodiaceae species is appreciated by livestock: dromedary, goat, and sheep. Its annual biomass production was, however, relatively low. Growth and mineral nutrients uptake was studied in high salinity condition (nutritive solution added with different NaCl concentrations up to 800 mM or seawater). On nutritive solution, higher biomass production was obtained for NaCl concentrations not exceeding 300 mM. At this concentration, plants were able to provide photosynthetic organs with suitable nitrogen and to use Na+ in osmotic adjustment. Above 300 mM NaCl-salinity, growth was severely affected, and Na+ and Cl- were accumulated at the expense of K+, Ca2+ and reduced nitrogen. Grown on diluted or undiluted seawater, this plant expressed low biomass production potential. Improving seawater with mineral elements led to a net growth improvement, particularly in plants cultivated on diluted seawater (50%). These plants were even more productive than plants cultivated on nutrient solution. The results suggested that nitrogen was the most growth limiting nutrient for culture on seawater.