Calli obtained from two sugarcane cultivars (R570 and CP59-73) were exposed to different osmotic
stress intensities followed by a period of stress relief. Relative rate growth, callus water content and
changes in organic and inorganic solutes were determined at the end of stress and relief periods. After
the stress period, calli derived from both cultivars showed a decrease in RGR, but at lesser extent in
R570 than CP59-73 cultivar. Same tendency was recorded in the callus water content under mannitolinduced
osmotic stress. The inorganic solutes seemed to have no contribution in the osmotic
adjustment in mannitol-stressed calli since K+ and Ca2+ concentrations decreased drastically while Na+
and Mg2+ concentrations were not affected. The accumulation of proline occurred in both cultivars and
was more marked in CP59-73 than R570 cultivar. At the end of the relief period, we observed that all the
considered parameters have recovered completely to reach the control levels. According to these
results, we conclude that the drought stress-induced changes are reversible, at the least at the cellular
level, in sugarcane cultivars.