Effects of drought stress on seed germination and seedling growth of Amsonia tabernaemontana

Effects of drought stress on seed germination and seedling growth of Amsonia tabernaemontana were studied by using a method of simulated drought stress with different concentrations of PEG6000. The results showed that, 1) seed germination rate and germination index of A.tabernaemontana were improved by a low concentration of PEG (5％) treatment. With increasing the concentration of PEG, the germination rate declined, however, the seeds could germinate after rewatering. 2) The leaf relative electrical conductivity and malondialdehyde (MDA) content significantly increased with increasing extent and duration of drought stress. There was significant positive correlations between proline content and leaf relative electrical conductivity and malondialdehyde content. When concentrations of PEG increased to severe stress, proline contents increased significantly, while activities of SOD and POD decreased after an initial increase.