Studying the response of seed germination of neglected plant Arugula (Eruca sativa L.) to some environmental factors

Introduction Arugula (Eruca sativa Mill.) is an annual plant of Brassicaceae family, that grows in a wideareas of Iran from Sistan and Baluchistan in southeast to coast of the Caspian sea in north. This plant is known as a weed in some regions. However, it has attracted attentions in recent years due to various medicinal and forage uses, as well as having valuable traits such as high vegetative growth, high growth rate, excellent resistance to the biotic and abiotic stresses, and high genetic diversity. Considering the importance of the successful germination and seedling establish mention the survival of plants and also to achieve the optimal plant density of crops, and the effect of environmental factors on it, this experiment was conducted to investigate the effect of environmental factors such as temperature,water potential, salinity, pH and planting depth on the germination and emergence in Arugula.

Materials and Methods All experiments were conducted in randomized completely design with four replications Initial germination test revealed no dormancy of gathered seeds. In order to study the effects of temperature on germination percentage and rate, seeds were placed in cold incubators with temperatures of 2.5, 5, 10. 15, 20, 25, 30, 35, 38 and 40 °C. The effect of water potential (0, -0.2, -0.4, -0.6, -0.8, -1, -1.2, -1.6 and -1.8MPa), salinity (0, 50, 150, 200, 250, 300 350 and 400 Mm) and pH (3, 4, 5, 6, 7, 8 and 9) on seed germination were conducted under optimal temperature and effect of planting depth (1, 2, 3, 5, 7 cm) on seedling emergence was carried out in a greenhouse condition.

Results and Discussion Arugula seed germination occurred in a wide range of temperatures. Optimum temperatures for Arugulaseed germination were estimated 30.55 °C. Arugula showed a high tolerance to drought and salinity stresses. Drought and salinity stresses that reduces the germination of this plant to 50% were -13.36 MPa and 267.53 Mm, respectively.The maximum germination percentage (98%) was observed in pH 7 and any increase or decrease in pH resulted in decrease in germination percentage and rate. the highest emergence percentage (95%)were observed at a depth of 2cm, and further increase in seeding depth caused a decrease in emergence percentage.

Conclusions. In general, results of this study showed germination and emergence of winter rapeseed affected to different levels of temperature, water potential, salinity, acidity and placed planting depth. And these parameters can be used to predict the time to germination or emergence of Arugula in normal conditions.