ABSTRACT
The present investigation was carried out to study the effect of post-emergence soil treatment with different salinity levels (0.0, 100, 150 and 200 mM NaCl) on growth, endogenous phytohormones, yield components and some biochemical activities of the yielded seeds of Vicia faba plants. The results indicated that increasing of salinity up to 200 mM showed significant decreases in growth parameters at fruiting stage and yield components. On the other hand, the levels of IAA, GA3 decreased, while ABA level increased with salt stress. Biochemical activities of the yielded seeds such as carbohydrate contents and total protein significantly decreased as compared with non-salinized plant, while salt stress induced the accumulation of the total phenol and proline contents. In addition, the content of Na+ increased significantly under salinity stress, while K+, Ca+2 and P+3 contents were decreased, when compared with those of the control. Application of stigmasterol by seed soaking, counteracted the adverse effects of salinity through inducing significant increases in all growth criteria at fruiting stage, yield components, levels of IAA, GA3, soluble, insoluble and total carbohydrates, total protein concomitantly with decreases in total phenols, proline content and level of ABA as compared with those of the reference plants. Also, treatment with stigmasterol resulted mostly in a decrease of Na+ accumulation concurrently with significant increases of K+, Ca+2, P+3 contents, K+/Na+ and Ca+2/Na+ ratio when compared with those of the reference controls. These results indicate the role of stigmasterol in increasing the tolerance of Vicia faba plants to salt stress. Three prominent types of modifications were observed in the protein patterns of yielded seeds, some proteins were disappeared, other proteins were selectively increased and synthesis of a new set of protein was induced, some of these responses were observed under stigmasterol and salinity, while others were induced by either stigmasterol or salinity.
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