Response of the root of Eucalyptus camaldulensis Dehnh. to drought stress

Root distribution of three-year-aged Eucalypt (Eucalyptus camaldulensis Dehnh.) seedlings was determined under different soil moisture regimes in Yazd, Shahid Sadoge Desert Research Station. The seedlings were grown in lysimeters which subjected to three soil moisture regimes including; 100% (well watered), 70% (medium drought stress) and 40% (high drought stress) of field capacity (FC). Soil moisture was restored by adding the required volume of water in the basis of time domain reflectometry (TDR) reading taken from tubes installed in each lysimeters. The roots were harvested at 0-30, 30-60, 60-90 and 90-120 cm depth of the soil at the end of the experiment. Results showed that root dry weight and length decreased significantly when soil water content reduced (P <0.001). The effects of various soil moisture content treatments on root dry weight and length distribution at different depths of soil were significant (P< 0.001). Therefore, deep root development of E. camaldulensis was related to soil moisture content and intensive soil drought stress inhibited root growth in high depth of soil.