#cacl2

Salinity is one of the environmental factors that has a critical influence on the germination of seeds and plant establishment. Seed germination is the stage which is most susceptible to this abiotic constraint. The objective of this study was the identification of the kinetics of germination in response to salinity stress. Two experiments were separately conducted using various salinity levels of 0, 50, 100, 150, 200, 250, 300, 400 and 600 meq.L-1 created using NaCl as first experiment and by CaCl2 at the same levels in the second experiment. The seeds of two Acacia species (Acacia decurrens and Acacia saligna) were used in each experiment. The germination was evaluated in Petri dishes based on the daily rates and the cumulated rates of germination seeds over a period of 21 days. Germination of these species decreased with increasing salinity. All Acacia species showed higher tolerance to increased level of CaCl2 than to NaCl. The recovery of the seeds that did not germinate under salinity conditions using NaCl or CaCl2 at (600 meq.L-1) indicate that the sodium chloride were toxic at this concentration and thus the adverse effects of CaCl2 concentration that explained as a result of lowering osmotic potential of the external solution. High significant results indicated that the NaCl presented higher toxic effects on germination parameters than the CaCl2. Furthermore, Acacia decurrens was more tolerant than Acacia saligna with a rate of considerable germination of 46% with the concentration of (300 meq.L-1) of NaCl.