(100-49) Effect of salt-tolerant clonal rootstocks on growth, physiological attributes and antioxidant activities in “Old Limachino Tomato” plants under saline growing conditions
Agronomist Instituto de Investigaciones Agropecuarias (INIA) Rengo, Libertador General Bernardo O'Higgins, Chile
Body of Abstract: Salinity is a major environmental constraint for agriculture in several areas of the world including Chile. Tomato is considered a salt-sensitive plant species and salinity drastically reduces its productivity and fruit quality. Grafting procedure has been recommended as a promising strategy to improve salt resistance in this species. The purpose of this study was to investigate the effect of salt tolerant rootstocks issued from interspecific cross between cultivated S. lycopersicum and wild relative halophyte S. chilense on growth and physiological parameters in “Old Limachino Tomato” (OLT) grafted plants under saline stress (NaCl) at the vegetative stage. Grafted, self-grafted and non-grafted OLT plants were cultivated at different levels of stress salinity by adding different concentrations of sodium chloride (NaCl) within a nutritive solution (0 and 160 mmol L-1 of NaCl). Theses saline stress was imposed seven days after transplant and maintained for 21 days. The growth of shoots and roots, water status, chlorophyll fluorescence and chlorophyll, MDA and protein contents in leaves were evaluated. In parallel, antioxidant capacity (FRAP and DPPH), non-enzymatic (glutathione, ascorbate and polyphenol contents) and enzymatic activities (APX, CAT, DHAR, GST and GR) were measured. Proteins and chlorophyll levels were increased by salt stress, with no significant differences by grafting type. The MDA contents were increased by the effect of salinity in both non-grafted and self-grafted OTL. However, it remained stable in plants grafted on the resistant rootstock, but with showing higher contents. It was observed that the antioxidant capacity (FRAP and DPPH) and antioxidant activity increased during the salinity stress, but they were less affected in OTL plant grafted on the tolerant rootstock. In conclusion, these results suggest that the salt-tolerant rootstock stabilize (less modified) the antioxidant capacity (FRAP and DPPH) and activity in OLT grafted, in comparison with non and self-grafted OLT plants under saline conditions.