Effects of salinity on growth and compatible solutes of callus induced from Populus euphratica

The present study aimed to evaluate the response to salinity of Populus euphratica, which is more salt-resistant than other poplar cultivars, at the cellular level. To this purpose, callus was induced from shoot segments of P. euphratica on Murashige and Skoog (MS) medium supplemented with 0.5 mg l(-1) (2.2 muM) 6-benzyladenine (BA) and 0.5 mg l(-1) (2.7 muM) 1-naphthaleneacetic acid (NAA). Callus was transferred to MS medium supplemented with 0.25 mg l(-1) (1.1 muM) BA and 0.5 mg l(-1) NAA. The relative growth rate of callus reached a maximum in the presence of 50 mmol l(-1) NaCl and growth was inhibited with increasing NaCl concentrations. Examination of the changes of osmotic substances under salt stress showed that accumulation of proline, glycine betaine, and total soluble sugars increased with increasing salt concentrations. The results indicate that the response of the callus of P. euphratica to salt stress is similar to that of the whole plant.