The ecophysiology of some endemic halophyte plants around the Salt Lake

Salt tolerance mechanisms of 30 endemic halophyte species which belongs to different families that are natives of Salt Lake area were investigated in terms of the changes in amounts of photosynthetic pigments (chlorophyll a, chlorophyll b and total chlorophyll contents), inorganic ions (Na+, Cl-, K+, Ca+2 ve Mg+2) and organic compounds (glucose, fructose, proline, glycinebetaine, choline-O-sulphate, choline ve ß-alaninebetaine). Differences between taxa, families and seasons were analyzed and their relationships with the changes of the amounts of the water content percentage, pH, EC, soluble anion (HCO3-, Cl-, SO4-2) and cation (Na+, K+, Ca+2, Mg+2) of the soil were determined.It has been observed that the stations where the investigated taxa were collected showed differences in soil properties and salt type which were found to be having an effect on plant life in the area, according to their distances to lake and season. It has been determined that either NaCl or Na2SO4 or both of these salt types are dominant at the stations been studied on. Some taxa were collected from only one station, whereas the others were collected from two or three stations.It has been observed that there are differences in inorganic ion and organic osmolyte contents of taxa. Taxa were classified into 5 groups by cluster and factor analyses: Na+, Cl- and glycinebetaine accumulators, glucose and fructose accumulators, choline-O-sulphate and ß-alaninebetaine accumulators, K+ accumulators and proline accumulators. Taxa that are members of Chenopodiaceae were found to be having the least proline content, on the other hand very high levels of glycinebetaine, Na+, Cl- and Na+/K+ ratio. Na+/K+ ratio of Lepidium caespitosum (Brassicaceae), which showed a high proline, Na+ and at the same time K+ content, was appeared to be exceeding the value of 1 but lower than that of Chenopodiaceae members. Na+/K+ ratios of Hypericum salsugineum (Hypericaceae) and monocotyledones, which contain the least concentrations of Na+, Cl- and K+ are lower than the value of 1 whereas they have higher fructose content than all other taxa. Taxa that are having high amounts of quarternary ammonium compounds, choline-O-sulphate and ß-alaninebetaine, were determined as members of Plumbaginaceae. Some dicotyledone taxa were found to be apart from those groups with their weak similarities. Seasonal changes of the investigated plant parameters were evaluated in 13 taxa and it was determined that their chloropyhll a/b ratio, chloropyhll a, Ca+2, Mg+2, glucose and fructose contents were decreased in the last inflorescence period. Roles of those parameters in the salt tolerance mechanisms were discussed.