Preliminary Study on Drought Resistance of Four Broadleaved Seedlings under Water Stress in South China

The drought resistance of Michelia macclurei, Elaeocarpus sylvestris,Schima superba and Castanopsis fissa seedlings was studied under artificial simulated water stress by using PEG-6000. The results are as follows: With the water stress increasing, the decrease of relative water contents in leaves of M. macclurei and S. superba seedlings was relatively small, followed by E. sylvestris, whereas that of C. fissa was the largerest. The relative conductivities of leaves of M. macclurei and S. superba seedlings increased slightly, followed by E. sylvestris, whereas that of the C. fissa increased greatly. The contents of free proline in leaves of M. macclurei and S. superba changed a little, whereas those of E. sylvestris and C. fissa increased significantly compared to the controls. The contents of soluble sugar in leaves of the four seedlings tended to increase with increasing stress intensity;the chlorophyll contents in leaves of the four seedlings fluctuated slightly with increasing stress intensity; the activities of SOD in leaves of M. macclurei and S. superba seedlings were significantly greater than that of the controls, and that of E. sylvestris was significantly smaller than the control, whereas that of C. fissa seedling was close to the control under severe stress with 36 hours. The content of MDA slightly increased for M. macclurei seedling, significantly increased for E. sylvestris seedling, kept steady for S. superba seedling and greatly increased for C. fissa seedling. The drought resistance of the four seedlings was evaluated with principal component analysis, indicating that their drought resistance was in the order of t S. superba>M. macclurei>E. sylvestris>C. fissa.