Effects of salinity, temperature and light on germination of invasive Prosopis juliflora (Sw.) DC

Effects of salinity, temperature, light and their interactions on the rate and final percentage of germination were evaluated for the invasive shrub Prosopis juliffora, grown under arid environmental conditions of the United Arab Emirates (UAE). Seeds that were not treated with NaCl germinated well in a wide range of temperatures and in both full light and complete dark. Seed germination decreased significantly with the increase in both NaCl concentration and temperature. Optimal germination percentage occurred at 25 degrees C. The inhibitory effect of high salinity on final germination percentage was greater at 40 degrees C than at 15 and 25 degrees C. Germination was completely inhibited in 400 mM NaCl at 40 degrees C and in 600 mM NaCl at 25 degrees C. However, germination rate was significantly greater at 40 degrees C than at 15 and 25 degrees C in lower salinities and the reverse was true at higher salinities. Germination in light was significantly greater than in the dark at lower salinity levels and high temperature. (c) 2004 Elsevier Ltd. All rights reserved.