Novel and widely spread citrus rootstocks behavior in response to salt stress

Irrigation water salinity is a major limiting factor in arid and semi-arid environments. The use of rootstock is one of the appropriate agronomic techniques that attempt to support and limit the negative effect of salinity. The objective of this study was to evaluate the behavior of eight one-year-old rootstocks grown in pots under salt stress conditions (30 and 60 mM NaCl). Some genotypes, i.e. C35 citrange, Bitters, Carpenter and Furr citrandarins were recently released or spread and poor information on their behavior in saline conditions is available, while Carrizo citrange, Swingle Citrumelo, Citrus volkameriana and Citrus macrophylla are spread since long ago in the Mediterranean basin. The results clearly demonstrated that the most salt sensitive genotypes were Carrizo and C35 citrange, that reduced morphological and gas exchanges performances. Furr, Bitters and Carpenter citrandarins revealed good physiological and hormonal behavior. An intense antioxidant enzymatic activity was noted in C35 and Carrizo citranges, while Furr showed a decrease in malondialdehyde and antioxidant enzymatic activities at 60 mM NaCl. Its tolerance to saline water was also confirmed by transcriptomic analyses.