Physiological Responses of Five Native Wild Shrubs to PEG Drought Stress

Using PEG- 6000 to simulate drought stress,we determined and analyzed the 5 physiological indexes( relative water content,relative electrical conductivity,MDA content,soluble sugar content,and proline content) of leaves of five common wild shrub species in South China,explored the change rule of various physiological indexes of different species under different intensities of drought stress,and conducted the comprehensive evaluation of the drought resistance of these species by principal component analysis. The results indicated that the leaf relative water contents of all species were decreased along with the intensification of drought stress,while Maclura cochinchinensis,Syzygium buxifolium,Syzygium tephrodes,and Cassia corymbosa also maintained higher leaf relative water content under serious drought stress. The relative electrical conductivity and MDA content all increased with the extension of stress duration. The contents of proline and soluble sugar in most species somewhat increased as the stress duration prolonged. The principal component analysis was carried out,and the result showed that the drought resistance of 6 shrub species had the following order: Syzygium buxifolium Syzygium tephrodes Maclura cochinchinensis Rosa multiflora var. cathayensis Cassia corymbosa Ficus formosana.