Abstract:Cultured sugarcane(Saccharum sinensis Roxb.) cell line R8968 was selected for resistance to growth inhibition by hydroxyproline(HYP), a proline analog. Comparison of the free amino acid pool level in the line with that of the HYP-sensitive donor showed substantial accumulation of proline(3.8 × ). The responses of the cell line R8968 to NaC1, freezing temperature and PEG were also compared with those of the donor and the former exhibited remarkably increased tolerance to the tested conditions. The results showed that proline accumulation may favour the increased tolerance.