In Vitro Response of Two Citrus Rootstocks to Salt Stress

The in vitro response of two citrus rootstocks (sour orange, Citrus aurantium L. and Volkamer lemon, Citrus volkameriana Ten. & Pasq.) to two types of salts (NaCl and CaCl2) of different concentrations (0, 50, 100, 150, 200, or 300 mM) was investigated. Results showed that increasing NaCl level in the growth medium led to increased Na and Cl accumulation and decreased Ca concentrations in plant tissue. Increasing CaCl2 levels in the growth medium led to increased Ca accumulation and decreased Na concentrations in plant tissue. Plant K concentrations decreased with increased salinity level in the media. In general, increased salinity level in growth medium, using NaCl, CaCl2, or a combination of the two, led to reduced plant growth (leaf number, plant length, fresh weight, dry weight, and increased plant leaf damage) in Volkamer lemon and sour orange after two months in culture.