Assessment of Seed Germination of Moringa peregrina under Drought and Salinity Stress and its Cardinal Germination Temperatures in Laboratory Environment

Abstract

The effect of different temperatures on germination was assessed in a laboratory study in the framework of complete randomized design with five repetitions to determine the specific temperature of Moringa peregrina seeds. Evaluation of germination response was conducted at constant temperatures of 5, 10, 15, 20, 25, 30, 35, 40 and 45 °C. Cardinal germination temperatures were fitted using three models, including beta, segmented and dent-like. Optimum and maximum temperatures of germination were calculated 17, 25-30 and 47 °C, respectively, based on the dent-like model, which was identified as the best model using statistical indicators. Then, to investigate germination and seedling growth response of Moringa peregrina toward different levels of salinity and drought stress at an optimum temperature, another test was conducted. In this experiment, seed germination was assessed in four levels of salinity and drought with the osmotic potential of 0, -4, -8 and -12 bar. The results indicated that seed germination speed and percentage were decreased due to drought and salinity stress. Generally, seed germination of Moringa peregrina was more sensitive to drought stress than to salinity stress.