Effect of Sodium Chloride on Nitrate, Ions Accumulation and Nitrate Reductase Activity in Two Rootstocks of Almond

Limited data published about the effects of salinity on nitrogen assimilation of fruit trees such as almond. A greenhouse experiment was conducted to study the effect of sodium chloride (0, 75 and 150 mM NaCl) on nitrate reductase activity, accumulation of nitrate, proline and some ions in the seedlings of two almond rootstocks (Prunus dulcis L.). The results showed that application of 150 mM sodium chloride significantly decreased the total dry weight in the seedling of “Bitter Almond” (2.68 g). In the seedlings of “Sweet Almond” treated with 150 mM sodium chloride, the leaf proline content increased significantly (140 µg. g FW) after 14 days, however, the proline content in leaves of both rootstocks (“Sweet Almond” and “Bitter Almond”) was decreased after application of 150 mM for 21 days (43.66 and 47.8 µg. g FW, respectively). Also, sodium chloride decreased the leaf nitrate reductase activity in leaves of both rootstocks. The interaction of effect sodium chloride and salinity duration on Na+, K+ and Cl- concentration was significant. The results suggested that the changes in nitrate content and nitrate reductase activity in almond rootstocks after NaCl treatment is an important biochemical index during salinity treatment and may be resulted to disruption in nitrogen assimilation in almond seedlings.