الفهرس 
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Abstract
Salt tolerance of four Egyptian Vicia faba L. cultivars – Nubaria 1, Nubaria 2, Sakha 1 and Giza 3 – was investigated at germination. The response of early emergence of the embryo to salt stress seems to differ from that of the subsequent extension of embryonic axis; since based on magnitude and speed of germination Nubaria 1 was the most salt sensitive cultivar but exhibited relatively high salt tolerance on the basis of embryo growth.
Photosynthesis rate was reduced under salinity in both the tolerant and resistant cultivars. However, in the tolerant cultivar Nubaria 1(tolerant), was suggested to be due to stomatal limitation while to the toxic ion effect on the photosynthetic machinery in Nubaria 2 (sensitive).
The reduction in K+ concentration of plant tissue in response to salinity was such that the proportion of K+ allocated to the foliage was reduced in favor of RKR. In addition, the increase in Na+ concentration in response to salinity was such that stem accommodates greater proportion of the absorbed Na+ than does root and leaves. This points to appreciable role of stem in providing K+ to and retention of Na+ away from leaves and root under salinity stress, which was more evident in Nubaria 1 than Nubaria 2 and points also to a limited capacity of root to sequester Na+.
SA had a role in alleviation of salt stress in Nubaria 1. This was accompanied by increasing stomatal conductance resulting in increasing the photosynthesis rate. SA also improved pigment concentration, proline content, protein content which collectively can be a cause of increasing growth. In addition, it caused decreasing in free phenolics, flavonoids and MDA; denoting decreased ROS, particularly H2O2 as a result of raising guaiacol peroxidase and APX which in turn could be a cause of stomatal opening.
At the gene level, the most striking result was the increase of AAPK expression with stomatal opening, suggesting a possible role of AAPK in negative control of stomatal closure, which will be the first report suggesting this.