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Salt stress is a major abiotic stress that limits agricultural productivity in many regions of the world. To understand the molecular basis of the salt stress response, two wheat (Triticum durum Desf.) cultivars, Karim and Azizi, which are of agronomic significance in Tunisia, were grown under non-saline and saline conditions (100 mM). Leaves and roots of control and salt-stressed plants were harvested after 11 days of salt treatment. Karim cultivar may behave as a typical Na+ include, which compartmentalizes Na+ within the leaf cell vacuoles where it could be used as an osmoticum to lower the osmotic potential necessary for the maintenance of the plant hydric status. While, accumulation of K+ was greater in Karim cultivar compared to Azizi, in both organs, presenting an important manifestation of salinity tolerance. Significant changes in metabolism of antioxidative system were observed, with an increase in protein tyrosine nitration, which indicates that salinity stress induces a nitro-oxidative stress. [ABSTRACT FROM AUTHOR]

The present study investigated the possible mediator role of salicylic acid (SA) in alleviating cadmium (Cd) toxicity during the germination stage of barley. The exposure of barley seedling to increasing Cd concentrations (25, 50 and 100 µM) during early stages of their establishment, caused a gradual decrease in vigour index, root length, α-amylase, acid phosphatase, alkaline phosphatase activities in endosperms and mitotic index of the root tip. Seed pretreatment with 600 µM SA partially alleviated the negative effects of Cd on germination parameters and increased the hydrolytic enzyme activities and mitotic index. Cadmium treatment increased Cd accumulation in roots. Furthermore, results showed that compared to the cadmium treatment applied alone, SA pretreatment of the seeds did not influenced the Cd concentration in the roots. These results suggest that SA plays a positive role in barley-seed germination and early seedling growth by protecting it against Cd toxicity by moderating its toxic effect on the mobilization of organic reserves. [ABSTRACT FROM AUTHOR]

To assess cadmium (Cd) and copper (Cu) phytotoxicity, barley (Hordeum vulgareL. var. ‘Manel’) seeds were germinated for a period of 2 days in a solution containing CdCl2(25, 50, and 100 µM) or CuSO4(100, 300, and 500 µM). The growth of radicles and shoots decreased while the water content in stressed seeds remained near control values. A decline inα-amylase, acid phosphatase, and alkaline phosphatase activities was also observed in endosperms, whileβ-amylase activity was only slightly modified by heavy metal treatments. Furthermore, Cd and Cu increased lipid peroxidation, enhanced soluble protein and sugar content even at the lowest dose, and induced a significant accumulation of proline, essentially in radicles. A synthesis of the results reveals that the inhibition of seed germination after exposure to Cd or Cu is not a consequence of reduced water uptake by seed tissues, but may be due to a failure in reserve mobilization from the endosperm. [ABSTRACT FROM AUTHOR]