Physiological response of the facultative halophyte, Aeluropus littoralis, to different salt types and levels

Abstract

The present study investigated the effects of NaCl, KCl and Na2SO4 salts on the C4 excreting halophyte Aeluropus littoralis in relation to growth, mineral status and photosynthesis in greenhouse conditions. Plantlets were subjected to five salinity levels: 0, 200, 400, 600 and 800 mM for 30 days. Growth decreased progressively with salinity increase, its reduction might be correlated with the high sodium (and/or chloride) accumulation in plant tissues, the decrease of leaf water status and the decline of the net photosynthetic rate and the intrinsic water use efficiency. Na2SO4 appeared more toxic than KCl and NaCl, especially at 200 mM. At 200 mM, Na2SO4 reduced plant growth by 61% while for other salt forms, the reductions were less than 20%. At this salt level, stomatal conductance showed a consistent pattern with plant growth and could adequately explain the variations between the effects of the three salt types.