In vitro responses of grape rootstocks to NaCl

An investigation was undertaken to adjudge the in vitro salt tolerance and biochemical changes due to NaCl on four grape rootstocks (Dogridge, SO4, H-144 and 3309C). The in vitro two-node micro-cuttings from the established cultures were sub-cultured on rooting medium comprising Murashige and Skoog (MS) basal medium supplemented with 0.5 μM indolebutyric acid (IBA), 200 mg dm⁻³ activated charcoal and different NaCl concentrations ranging from 0 to 125 mM. The surviving and proliferated cultures were further sub-cultured four times on respective media. Dogridge and H-144 tolerated 125 and 100 mM NaCl, respectively, while SO4 and 3309C survived only up to 75 mM NaCl. Contents of proteins, proline, K⁺ and Na⁺ in tissue increased in all genotypes due to NaCl supplementation, while contents of chlorophyll and total soluble sugars declined. Higher K⁺/Na⁺ ratio was registered in Dogridge and H-144 than in SO4 and 3309C. The relative NaCl tolerance for different grape rootstocks under study could be ranked as Dogridge > H-144 > SO4 and 3309C.