Seedling Tolerance of Three Eucalyptus Species to a Short-term Flooding Event: Tolerance and Physiological Response

Abstract

Research was conducted at Curtin University (Western Australia) to assess the seedling tolerance of three species Eucalyptus, gomphocephala DC (Myrtaceae) (common name ‘Tuart’), Eucalyptus marginata Sm. (common name ‘Jarrah’) and Corymbia calophylla (Lindl.) K.D. Hill & J. A. S. Johnson (common name ‘Marri’) to soil-induced stressor, namely water loggings (flooding). Flooding treatment was achieved by filling the tubs with water, approximately 1 cm above the soil surface and control treatment had the same method except with drainage holes. Study assessment was attained by statistical change in seedling growth, leaf allocation and leaf physiology after 70 days of seed germination. Tolerance was assessed by measuring changes in seedling growth, leaf allocation and leaf physiology after 70-80 days. C. calophylla was the most tolerant to prolonged waterlogging (80% survival, no difference in transpiration rates); E. marginata was the least tolerant (10% survival, 95% decrease in transpiration rate). E. marginata was the least tolerant to the three soil stresses. E. marginata prefers habitats that are not excessively wet on well-drained soils. C. calophylla was the most tolerant, occurring and tolerating wet, well-drained soils and thus demonstrated better tolerance to prolong waterlogging. Knowing the seedling growth and physiological responses of three prominent studied eucalypts to soil-induced stresses provides us with invaluable knowledge for rehabilitating and restoring urban bush land.