m.a. hakimzadeh

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

One of the reasons for soil salinization is the accumulation of salts in it by transmission through water and wind. In order to investigate the phenomenon of transfer of salts with dust in the arid regions of the north of Yazd- Ardakan plain, field samples were taken using 32 MDCO sediments traps with uniform dispersion in an area of 20,000 hectares at some stage in 4 seasons of 2017. After washing the sediment collector with a liter of distilled water in the field and transferring the samples to the laboratory, for the quantitative analysis of saline dust, similar to measuring the Water Electrical Conductivity (ECw), the Total Soluble Solids (TDS) were additionally measured through evaporation technique. The form and distribution of the dust particle size were additionally investigated using a Scanning Electron Microscope (SEM) tool. Within the qualitative examine of salts, effective cations and anions in salinity including Na+, K+, Ca++, Mg++, C1-, HCO-3 and SO-4 were measured The results confirmed that, in general, the fallout was 11.1 g.m-2 of soluble material with dust particles (13.28%) in the course of only 12 months. Particles with a diameter of 5 to 10 microns were the most frequent. Considering the high correlation between C1- and Na+ in the spring, autumn and winter, due to the high correlation between Ca++ and SO-4 in summer dust, sodium chloride (NaCl) and gypsum (CaSO4) 2H2O)), the most abundant composition of dust- containing salts could be expected in these seasons. By determining the percentage of solutes in the fallout dust, it was observed that the impact of the amount of the deposited salt from dust was slight and insignificant in the short time period; with the assumption of no change in the rate of subsidence, it was anticipated that it would explain the poor salinity in non- saline mass soils for up to 10 cm in 72 years. In general, the capability of airborne salt in increasing the soil salinity in the study area can be in long- term periods. Therefore, it is recommended to investigate other environmental effects of this phenomenon in order to identify its hazards.