Salt tolerance in Simmondsia chinensis: Water balance and accumulation of chloride, sodium and proline under low and high salinity

The response of jojoba [Simmondsia chinensis (Link) Schneid] plants to salinity was studied in solution culture. At concentrations of 0, 100, 200 and 600 m-mol l^-1 NaCI it was found that jojoba plants have high tolerance to NaCl. The growth of these plants was not affected by salinity. They accumulated large amounts of Cl^-, Na⁺ and proline. These amounts decreased rapidly in plants transferred back to control medium. Potassium content decreased in NaCl-treated plants and tended to increase rapidly to the control level in plants transferred to control medium. The effect of salinity on water balance was not appreciable. As suggested for other xerophytic species, it could be assumed that the high tolerance of jojoba to salinity plays an important role in its ability to endure periods of drought. The role of proline during or after stress remains an open question.