Combined effects of salinity and temperature on germination, growth and gas exchange in two cultivars of Sorghum bicolor

Excessive salinity in irrigation decreases crop's growth in arid regions such as Saudi Arabia. The aim of this research was to study the combined effects of salinity and temperature on germination, plant growth,F-v/F-m, gas exchange, chlorophyll and proline content in twoSorghum bicolorcultivars, Hindi and Jaizani. The treatments contained 3 temperatures (20 degrees C, 30 degrees C, 40 degrees C) and 4 NaCl concentrations (0, 50, 100, 200 mM). The results presented that as NaCl increased, germination, growth, gas exchange andF(v)/F(m)of the two cultivars declined, with great effects at 40 degrees C than at the other temperatures. Proline was higher in the Hindi and Jaizani cultivars at 20 degrees C and 30 degrees C under the different salinity conditions. On the other hand, the chlorophyll content was increased at 20 degrees C under increased salinity in both cultivars. The interactions between salinity and temperature significantly affected most measurements of the two cultivars; however, Hindi cultivar showed more tolerance toward stress.