Enhancement of acid phosphatase secretion and Pi acquisition in Suaeda fruticosa on calcareous soil by high saline level

The aim of this study was to identify the relationship between the adaptive processes of Suaeda fruticosa for Pi acquisition and the physic-chemical and biological characteristics of two soil types under moderate and high saline conditions. Four treatments were established in pots: namely SS100, SS600, CS100 and CS600 where SS stood for sandy soil and CS for calcareous soil, and the indexes 100 and 600 were NaCl concentrations (mM) in irrigation distilled water. Assuming that Pi per g of plant biomass is an indicator of plant efficiency for P acquisition, the results showed that Pi acquisition was easiest on SS100 and was difficult on CS100. The differences in Pi acquisition between plants on SS100 and CS100 could be attributed to the low root surface area (−30%) and to the low alkaline phosphatases (Pases) activities (−50%) in calcareous rhizospheric soil. The high salinity level had no effect on the efficiency of P acquisition on SS but increased this parameter on CS (+50%). In the latter soil type, hig...