Growth and water relation parameters in drought-stressed Coriaria nepalensis seedlings

In the present study, growth and water relation parameters were analysed in drought-stressed Coriaria nepalensis Wall. seedlings. C nepalensis seedlings were subjected to four drought cycles of 7, 14, 2 1, and 28-days, and to one control level (watered on alternate days) in a glasshouse. The seedlings failed to survive a 28-days drought during summer. Osmotic adjustment (defined as the decrease in osmotic potential at zero or full turgor in response to water deficit) was measured as the difference between the osmotic potential of seedlings watered on alternate days (control) and those subjected to 21-days drought cycle. Seedlings subjected to 21-days drought had a predawn water potential of -2.60MPa, and showed an osmotic adjustment of - 1.95 MPa at full turgor and -2.17 MPa at zero turgor. The growth of seedlings was positively related to moisture and with water potential. With decline in soil moisture the root:shoot ratio increased while leaf weight ratio decreased. Leaf characteristics, such as leaf number, leaf area, leaf area ratio, specific leaf area and leaf drop, were also affected by moisture stress. This study has indicated that osmotic adjustment is a major adaptive mechanism of C nepalensis that aids successful regeneration of seedlings in degraded sites with inhospitable soil conditions. (C) 2004 Elsevier Ltd. All rights reserved.