High salt induced oxidative damage and antioxidant response in tomato grafted on tobacco

One of the major limitations on agricultural development in many countries is the high salinity of the groundwater used in irrigation. Grafted plants may exhibit phenotypic variations from scion and rootstock plants in terms of abiotic stress tolerance, and be a method for improvement of tolerance in agricultural practices. The aim of the present study was to investigate response of Solanum lycopersicum L. ('Elazig') grafted on Nicotiana tabacum L. ('Samsun') and Nicotiana rustica L. ('Hasankeyf'), namely "Tomacco" plant (patent nr TR-2008-05391-B), to 10-d high NaCl irrigation. Physical development, chlorophyll a and b, total chlorophyll, total carotenoid, and anthocyanin levels were evaluated. Proline, lipid peroxidation, and electrolyte leakage levels were assayed in roots and leaves together with ascorbate peroxidase (APX) and catalase (CAT) activities. Considering alterations in chlorophyll contents, proline, malondialdehyde (MDA), and conductivity levels, and antioxidant enzyme activity levels scion and self-grafted plants seem to be more affected by salt treatments than tobacco and rootstock grafted plants. Tobacco roots seem to have better adaptive responses against salt stress in comparison to tomato as supported by changes in proline, APX, and CAT levels. Self-grafting experiments further supported grafting tomato onto tobacco rootstocks enhanced salt tolerance and adaptive response of scions and these changes seem to be dependent on rootstock rather than graft-induced changes. In conclusion, we demonstrated that previously defined graft unions of tomato on tobacco, which have increased fruit yield, had also enhanced tolerance to high salt stress and a promising technique for the cultivation of more salt tolerant varieties