Effect of interstock (`Salustiano orange) on growth, leaf mineral composition and water relations of one year old citrus under saline conditions

We investigated the effects of salinity on the growth, mineral composition (leaf, stem and root) and water relations in one year old plants of `Cleopatraʹ mandarin (Citrus reticulata Blanco) (CM), `Salustianoʹ orange (Citrus sinensis (L.) Osbeck) grafted on `Cleopatraʹ mandarin (CM/SAO), `Valencia Lateʹ orange (Citrus sinensis (L) Osbeck) on `Cleopatraʹ mandarin (CM/VLO) and `Valencia Lateʹ grafted on CM/SO (CM/SAO/VLO). Plants were grown in sand culture under greenhouse conditions and supplied with nutrient solution containing either 5 (control) or 50.mM NaCl. After ten weeks of salt treatment, the CM/SAO/VLO leaf growth was not affected, while CM/SAO showed the greatest leaf growth reduction. Root growth was less affected than leaf growth by salt treatment, and was similar for all four combinations. In the salt treatment, the leaf chloride concentration of CM/SAO/VLO was the lowest compared with the other plants and leaf Na concentration of CM/SAO/VLO was lower than CM/VLO, suggesting that the interstock limited Cl and Na uptake and/or transport from roots to leaves. The high leaf growth reduction observed in CM/SAO could be related to a decrease in turgor, due to a decrease in leaf water potential caused by salt treatment not being compensated by a reduction in leaf osmotic potential.