ارزیابی برخی خصوصیات فتوسنتزی دو رقم ارزن علوفه‌ای در شرایط تنش شوری

Abstract: Effect of different salinity levels (0, 50, 100, 150 and 200 mM NaCl) on photosynthetic characteristics and yield of two forage millet cultivars (Nutrifeed and Bastan) were investigated at this experiment. A factorial test based on randomized complete block design was conducted during 2010-2011 growing season in three replica-tions. The results showed that with increasing salinity, dry matter yield, leaf relative water content (RWC) and stomatal conductance were decreased.While, traits such as proline and relative membrane permeability (RMP), were increased as salinity level increased,. The highest total dry matter in control treatment of Nutrifeed millet (83.2 g. plant-1) was observed and the lowest was measured in 200 mM in the case of Bastan millet (23.5 g. plant-1). The Leaves relative water content of Bastan cultivar in the 100, 150 and 200 mM NaCl declined sharply and caused leaf necrosis. There were no significant differences between control, 50 and 100 mM NaCl in photochemical quenching of Nutrifeed cultivar. In Bastan cultivar, a significant difference between control and 50 mM NaCl was abserved. As salinity level increased, the proline in shoots of two cultivars increased. Stomatal conductance had a effective role in increasing the performance of dry matter of nutrifeed millet in salt stress conditions, and osmotic potential decreasing also improved dry matter conditions in this plant. Generally, photosynthetic characteristics of Nutrifeed millet were better than the Bastan millet.