Transmissible salt tolerance traits identified through reciprocal grafts between sensitive Carrizo and tolerant Cleopatra citrus genotypes

Abstract

In this work, reciprocal grafts between the chloride-tolerant Cleopatra mandarin (Citrus reshni Hort. ex Tan.) and the chloride-sensitive Carrizo citrange (Citrus sinensis [L.] Osb. x Poncirus trifoliata [L] Raf.) rootstocks were grown under saline conditions to identify major transmissible salt tolerance traits in citrus. The data indicate that lower chloride levels in leaves, attenuated shoot growth and smaller vessel size in xylem were the most important transmissible salt tolerance traits. Other tolerance attributes such as larger leaf area and lower transpiration rates were non-transmissible characteristics. Leaf cation levels and gas interchange parameters were unrelated to salt tolerance. In comparison with sensitive Carrizo, tolerant Cleopatra plants showed reduced capabilities for water uptake as well as lower leaf Cl-concentrations. Carrizo on Cleopatra grafts also possessed these two attributes although they were slightly less tolerant than Cleopatra plants, which had higher shoot to root ratios than the grafted plants. Cleopatra on Carrizo plants showed high sensitivity to salt because they had higher ability for water uptake and accumulated higher Cl-concentrations in leaves.