The effects of nitrogen supply and salinity on [DMSP], [glycine betaine] and [proline] concentrations in leaves of Spartina anglica

Spartina anglica tillers were grown for 7 weeks in a range of solutions con taining 0, 400 or 800 mM sodium chloride and 0 or 2 mM ammonium nitrate. Th e leaves were analysed for dimethyl-sulphoniopropionate (DMSP), [glycine be taine] and [proline] as well as total nitrogen and total sulphur. Total nit rogen concentrations in green leaf tissue of plants grown in the 2 mM nitro gen treatments were twice as high as those found in plants grown with no ad ded nitrogen, and were not affected by salinity. Total sulphur concentratio ns were not affected by any of the treatments. [DMSP] concentrations ranged from 4 to 48 mu mol g(-1) fresh weight. With no added nitrogen [DMSP] conc entrations decreased with increasing salinity, while the 2 mM nitrogen trea tments showed the reverse trend. [glycine betaine] concentrations ranged fr om 49 to 77 mu mol g(-1) fresh weight were unaffected by the treatments. [P roline] concentrations ranged from 3.1 to 50 mu mol g(-1) fresh weight and were positively affected by increasing salinity. (C) 2001 Elsevier Science B.V All rights reserved.