Document Type : Original Article
The present work aimed at investigating changes in growth and some metabolic activities in NaCl-stressed bean plants, and assessing the role of ascorbic acid to alleviate these changes. The field experiment was carried out to study the response of presoaked fava bean seeds (Vicia fava cv. Misr 2) in freshly prepared ascorbic acid (50 ppm ≈ 0.3 mM; as recommended dose as described by El-Tayeb, 1995) or distilled water (control) for 4 hrs at natural environmental conditions, to salinity stress during different growth periods. At vegetative stage, the fresh and dry weights were decreased with salt treatment. The shoot length was hardly, if at all, affected by salinity stress either in the plants treated with ascorbic acid or not. The pigment biosynthesis was substantially affected by salt treatment. Addition of ascorbic acid to stressed plants reduced the inhibitory effect of NaCl on pigment content. Salinity enhanced the accumulation of reducing sugars in both root and shoot of Vicia fava, particularly at the high level of NaCl during the vegetative stage of growth. Whereas, the salt stress caused a decrease in the sugars content of both plant organs during the flowering and fruiting stages. NaCl treatment caused a reduction in sucrose content of Vicia fava root at the high level of NaCl during vegetative stage. In addition, the polysaccharide content of roots and shoots gradually increased with the progress of age, except at fruiting stage. These findings suggest that ascorbic acid achieved better results during growth stages.