Effects of Salinity and Soil Phosphorus Application on Growth and Chemical Composition of Pistachio Seedlings

An experiment was carried out to assess the single and combined effects of salinity and phosphorus (P) on growth and chemical composition of pistachio seedlings (Pistacia vera L.) cv. Badami grown in a calcareous soil under greenhouse conditions. Pistachio plants were treated with four P levels [0, 60, 120, and 180 mg P kg-1 soil as calcium phosphate, Ca (H2PO4)2 center dot 2H2O] and four salinity levels [0, 1000 2000, and 3000 mg sodium chloride (NaCl) kg-1 soil] in a completely randomized design with three replications. The effects of different treatments of salinity and P on pistachio seedlings were evaluated in terms of leaf, stem, and root dry weight; leaf area; stem height; and chemical composition of seedlings. The results showed that these parameters were significantly affected in pistachio seedlings treated with salinity and P both singly and in combination as compared to the control. It is clear from this study that combined treatments of salinity and P have more negative effects on these parameters as compared to their individual treatments. Low levels of P application had no significant effect on leaf, stem, and root dry weights, decreased leaf area, and increased stem height, whereas greater levels of P significantly decreased leaf, stem, and root dry weight and stem height and had no significant effect on leaf area. Salinity decreased leaf, stem, and root dry weights; leaf area; and stem height. Salinity stress decreased leaf, stem, and root P concentrations as well as leaf K concentration and increased Na concentrations in these plant organs and stem and root K concentrations. Phosphorus application increased leaf, stem, and root P concentrations and leaf and stem Na concentrations, whereas it decreased root Na concentration and leaf, stem, and root K concentrations. Phosphorus application reduced proline concentration and increased reducing sugars content. Proline accumulation increased with increasing salinity levels, whereas the reverse trend was observed for reducing sugar content. These changes might have alleviated the adverse effects of salinity stress.