干旱区生态环境知识资源中心

Cleome amblyocarpa Barr. & Murb. is an annual herb in the family of Capparidaccac. It is abundant in sandy environments, and the gravel and stony grounds in Tunisian arid areas. Laboratory experiments were earned out to assess the effects of temperature (10 to 40 degrees C) on seed germination in complete darkness. The osmotic stress simulated by NaCl at different concentrations (0 to 200 mM) or polyethylene glycol 6000 (PEG-6000) at different osmotic potentials (0 to -1 MPa) was evaluated at the most suitable temperature found. Greatest germination percentage and rate of germination were obtained at 25 degrees C, but germination was inhibited by either an increase or decrease in temperature from the optimal temperature. The increase in osmolality of solutions induced by NaCl or PEG progressively inhibited seed germination. At 150 mM NaCl or osmotic potential of -0.6 MPa, germination was completely inhibited. There was a decrease in the rate of germination as osmotic stress was intensified. These findings suggest that C. amblyocarpa was able to tolerate well osmotically- and saline-stressful habitats of the arid ecosystems during germination stage.