Physiological Changes of Three Greening Seedling Species under Drought Stress

Studies were conducted on seedlings of Ficus microcarpa, Syzygium hainanense and Artocarpus nitidus ssp. lingnanensisunder simulated drought environment to study their physiological changes and then explore the effects of stress on the growth of seedlings. The result showed that, under drought stress, tissue water contents of the three seedlings tended to decreased, whereas thesoluble sugar content tended to increased; chlorophyll content of F. microcarpa and A. nitidus ssp. lingnanensisincreased first and decreased afterwards and S. hainanense increased gradually; protein content of F. microcarpa and A. nitidus ssp. lingnanensis increased and then kept steady, and S. hainanenseincreased first and decreased afterwards; the content of free proline of F. microcarpa and A. nitidus ssp. lingnanensis increased, whereas S. hainanense decreased slowly; the activity of SOD of F. microcarpa first decreased and increased afterwards, S. hainanense increased gradually, and A. nitidus ssp. lingnanensis increased first and decreased afterwards.The contents of MDA of F. microcarpa kept steady, whereas S. hainanense and A. nitidus ssp. lingnanensis increaseds. Principal component analysis indicated that drought resistance of the three seedling types was in the order of A. nitidus ssp. lingnanensis﹥S. hainanense﹥F. microcarpa.