Effects of Habitat Conditions on Some Secondary Metabolites, Photosynthetic Pigments, Minerals and Antioxidant Activities of (Haloxylon aphyllum Iljin.)

Black saxaul (Haloxylon aphyllum) is one of adapted species in desert and saline soils areas and grows in sand dunes and can be used for dune stabilization. Accumulation of metabolites leading to plant osmotic regulation. The relative importance of these substances varies depending on the plant species, habitat and intensity. Therefore, this experiment was conducted to investigate the effect of habitat conditions on photosynthetic pigments, antioxidant activity, amino acids, soluble sugars and ion content of black saxaul, in two areas in Bafgh, Iran under two soil conditions (saline sodic plaiya and non-saline sand dune) using a one way AMOVA with three replications in 2016. The results showed significant differences between two habitats for chlorophyll, carotenoid, anthocyanin, phenol and antioxidant activity (p<0.01). The higher values of these indices were observed in saline sodic plaiya habitat than to sandy habitat. In contrast, for amino acids, as: aspartic acid, glutamic acid, glycine and glutamine the higher values of 13.27, 13.66, 17.01 and 12.21 μg/g, respectively were obtained in sandy habitat than that that for saline sodic plaiya. For other amino acids, there were no significant differences between the two habitats. The higher values of soluble sugar 26.24 mg g-1 DW was obtained in sandy habitat that was significantly (p <0.01) higher than that for plaiya (13.26 mg g-1 DW). Overall, the results showed that improved the antioxidant activity, increased pigment content and modulated the ions concentration, especially the accumulation of potassium in plant organs play a key role in black saxaul osmotic regulation under salinity stress. The role of other osmolality nutrients such as amino acids and soluble sugars are more important for black saxaul growth in the sandy area with low salinity