The changes of relative leaf water content,electrical conductivity rate,proline content and malondialdehyde(MDA) of three Poa species at seedling stage were studied under water stress using pot experiment.The resulted showed that,with the water stress time prolonged,the leaf relative water content of each species decreased;while the electrical conductivity rate,proline content and MDA content increased.Comprehensive analysis indicated that the order of drought tolerance of this three species was P.pratensis...