[Physiological ecology responses of Scutellaria baicalensis to drought and rewatering]

To study the physiological ecology responses of Scutellaria baicalensis to drought and rewatering of short period, we tested and analyzed photosynthesis and chlorophyll fluorescence parameters of S. baicalensis leaves processed by different ways of water treatment in drought and rewatering period, characteristic indexes of physiology and biochemistry of root SOD, POD, PAL, C4H, etc. and accumulation dynamic change of root baicalin and baicalein. The result showed that along with the worsening drought, P(n), T(r), G(s) and F(v)/F(m) of S. baicalensis declined in different water supply, and F(o) increased. The response of SOD and POD's activity in S. baicalensis root to drought in I and II was earlier than it in III. The response time and increase range of baicalin accumulation existed differences in different water supply, and the indexes regained after rewatering. Therefore, photosynthesis of S. baicalensis changed and it destroyed the antioxidant metabolism balance when soil water content decreased resulting from drought. The synergistic effect of defence mechanism launched by S. baicalensis, SOD, POD, PAL, C4H, baicalin and baicalein reduced active oxygen's damage to the cell.