Abstract
The African rue (Peganum harmala L.) is an intriguing perennial herbaceous plant with medicinal benefits that grows in semi aridic soil in areas of steppe and sandy soils. In the present study, we collected the African rue plant from Harimla, Saudi Arabia, and analyzed the relationships among salinity lethal dose (LD), temperature and photoperiod, germination rate, changes in mean daily germination (MDG) and germination speed (T50). Therefore, the purpose of this study is to establish a high knowledge of the Peganum responses to the temperature, salinity, and photoperiod stresses and the interaction between factor affecting germination of African rue seeds. Seeds of Peganum were germinated for 28 d by soaking in distilled water or 100 mM, 200 mM, 300 mM and 400 mM of NaCl in variable dark/light conditions and temperature regimes (10-20, 15-25, 20-30 and 25-35 degrees C). At light germination, DL50 was attained at 100 mM NaCl for T (10-20 degrees C), 200 mM for T (15-25 degrees C), 300 mM for T (20-30 degrees C) and 400 mM for T (25-35 degrees C). DL100 was attained only at 300 mM for T (10-20 degrees C) and 400 mM for T (15-25 degrees C). At a high temperature (more than 25), DL100 was not reached. At dark germination, DL50 was attained at 0 mM NaCl for T (10-20 degrees C and 15-25 degrees C) and 100 mM for T (20-30 degrees C and 25-35 degrees C). DL100 was attained only at 100 mM for T (10-20 degrees C) and 300 mM for T (15-25 degrees C, 20-30 degrees C and 25-35 degrees C.