GENOTYPIC RESPONSES OF OLIVE PLANTS TO SODIUM-CHLORIDE

The effect of NaCl-salinity on growth responses and tissue mineral content was investigated for two olive (Olea europaea L.) genotypes of different vigor, Leccino and Frantoio. Forty-day-old self-rooted plants were grown for a 60-day period in a sand culture system supplied with a 1/2 strength Hoagland solution with the addition of 0, 12.5, 25, 50, and 100 mM NaCl. Plants were harvested at 12-day intervals, and the dry weights of shoot, and principal and lateral roots were evaluated. Relative growth rate (RGR) was also estimated. At the same time, plant tissues were analysed for N, P, K, Ca, Mg, Na, and Cl content. Growth inhibition by NaCl treatments was greater for Leccino than Frantoio plants. At the end of the experiment, 50 mM NaCl significantly reduced Leccino growth, while negative effects on Frantoio were detected only when using 100 mM NaCl. Leccino always accumulated more Na and Cl in the leaves than Frantoio. In a similar manner, Na/K ratio was always higher in the Leccino leaves compared to the Frantoio leaves. An inverse relationship between NaCl tolerance and vigor of the genotype emerged.