Effect of salinity and temperature on germination, growth and ion relations of Panicum turgidum Forssk.

Seed germination of Panicum turgidum was significantly affected by salinity levels, temperature and their interaction. Maximum germination was noted in the lowest saline media (25-50 mM) and distilled water at the temperature of 15-25 degrees C and 20-30 degrees C. Seeds germination was substantially delayed and reduced with an increase in NaCl to levels above 50mM. This trend was much pronounced under high levels of NaCl and incubation temperature. Low levels of NaCl (25-50 mM) stimulated shoot and root dry weights of P. turgidum seedlings. However, the highest NaCl levels (>100 mM) resulted in a significant decrease in shoot, root and total dry weights of seedlings. Intermediate degrees of temperature, 15-25 and 20-30 degrees C, resulted in a significant increase in biomass accumulation. The Na+ concentration in shoots and roots significantly increased as NaCl concentration increased. The K+ concentration in roots and K/Na ratio in shoots and roots was significantly reduced as salinity concentration increased. The K/Na ratio was greatly affected by higher NaCl concentration and incubation temperatures.