Salt tolerance among some citrus rootstocks

The response of five citrus rootstocks was studied with respect to salt tolerance. The plants were grown in nutrient solution salinized with Karoun lake water salt of final concentration of 10000 ppm lake salts. The results demonstrated a wide variation in respect to salinity. The relative salt tolerance was in the following ascending order: Cleopatra mandarin (c. reshni Hort. ex Tan), sour orange (c. aurantium L.), Amblycarpa (c. amblycarpa Ochse), Volkamer lime (c. volkameriana Pasq.) and Rangpur lime (c.limonia, Osb.).Growth of shoots was less affected by salinity than roots, so that shoot to root ratio increased for all five rootstocks, but to different degrees. The more tolerant the rootstock, the lower shoot to root ratio. Salt treatment increased Na and decreased K in all plant tissues of all studied rootstocks. The five citrus rootstocks were similar in the extent of Cl- loading in the roots, but differed in its accumulation in the leaves and to a lesser extent in the shoots. This indicated an upper limit to extent of Cl-loading in roots and rootstock differences in root to shoot transport of chloride. The ability of citrus plant to tolerate salinity seems to depend on its ability for chloride exclusion