Eucalyptus urocan drought tolerance mechanisms

The present study was designed to identify strategies for tolerance to hydric deficit in Eucalyptus urocan seedlings. The experiment was conducted in a green house with 100% solar radiation capture. The completely randomized block design was used with five treatments (plants irrigated daily with water corresponding to 25, 50, 75, 100 and 125% daily evapotranspiration) and five replications. 120day-old E. urocan seedlings (hybrid result from the crossing between Eucalyptus Urophylla x Eucalyptus camaldulensis) were planted in pots containing 8 L of substrate composed by oxisol, sand and muck at 3:1:0.5 ratio, respectively. The seedlings were irrigated with different volumes of water for 13 days and then analyzed. Under hydric deficit condition, E. urocan plants showed significant investment in the root system, reduced the breathing rate and kept enough turgor for growth. E. urocan plants at initial growth stage are tolerant to hydric deficit and show dehydration delay as a strategy to tolerate drought.