The effects of different soil water potentials, temperature and salinity on germination of seeds of the desert shrub Zygophyllum dumosum

The effects of different soil water potentials, temperature and NaCl concentration on seed germination of Zygophyllum dumosum Boiss., a common shrub in Israeli deserts, was investigated. Seeds had to be exposed to constant field capacity conditions (–0.0316 MPa) for a minimal period of two days before germination could start. Maximal germination under such conditions occurred after four days or more. Under simulated conditions of gradual dehydration of the soil, seeds were inhibited either at low soil water potentials (–0.10 to –10.00 MPa) or at high ones (–0.002 to –0.0398 MPa). Germination of Z. dumosum was independent of temperature in the range of 10–25°C, but strongly inhibited at 30 and 35°C. At 20°C germination was inhibited by salinity of the medium but still occurred (0.5%) even at a concentration of 0.5 M NaCl.