Eco-physiological adaptive strategies of Prosopis cineraria (L.) Druce in response to the diverse edaphic habitats of the Cholistan Desert, Pakistan

Salt stress is a significant environmental issue that harmfully affects plant growth and metabolism. However, plants tend to adapt to salt stress by regulating their biochemical and physiological attributes. Physio-biochemical responses to stress conditions of natural habitats remain unclear in Prosopis cineraria. This study evaluated the eco-physiological and biochemical adaptive strategies in P. cineraria growing under different edaphic habitats of the Cholistan Desert. Three edaphic habitats (Sand dune = SD, sandy plain = SP, saline area = SA) of the Cholistan desert were selected, each with three sub-sites as replicates. For the ecological study, five randomly positioned 10 m × 10 m quadrats were taken at each selected site. Physicochemical results revealed that at SD, EC was 9.4 dS m⁻¹, pH 7.5, and organic matter (OM) 0.78%. At SP, EC increased to 157.7%, pH to 9.33%, and OM to 20%. The soil Na+ level at SD was 1650.8 mg L⁻¹, but at SA, it was 200.8% compared to that of SD. The physiological attributes of the plant were significantly modified in a high-saline area, as chlorophyll a and b declined considerably by 34.26% and 54.32%, respectively, at SA compared to those of SD. Total soluble proteins, free amino acids, soluble sugars, proline, and root tissue contents of Na+, K+, Ca2+, and Cl- were considerably higher at SA. In wild populations, these physiological changes appeared to be crucial for sustainable survival in the arid, saline desert environment. Prosopis cineraria was identified in all edaphic habitats and showed ecological dominance at the saline area in the Cholistan Desert, indicating its particular adaptability to the salty environment.