Differential Effects of Four Abiotic Factors on Seed Germination and Seedling Growth of Rangeland-Medical Plant, Wild Mustard (Sinapis arvensis L.)

The aim of this study was to determine the effect of drought stress induced by using polyethylene glycol (PEG), heavy metals (Cd and Ni), and salinity (NaCl) on germination and seedling growth of Sinapis arvensis, an important medicinal plant in the Brassicaceae. The Sinapis arvensis seeds treatments contained i), control ii), PEG (5%, 10%, 15%), iii) NaCl (50, 100, 150 mM), iv) Cd+2 (50, 100, 150μM), and v) Ni+2 (50, 100, 150μM). The experiment used a randomized complete block design with 4 replicates per treatment. The experiments were performed in a programmed incubator at 25±2oC. Seed germination was recorded every day for 16 days. The root and shoot lengths of seedlings were measured after 16 days of incubation. Then, the seedlings were dried and root and shoot dry weights were measured. The results showed that germination percentage reduced with increasing concentrations of the tested factors. The maximum germination (97%) was observed in PEG (5%) and the minimum germination rate was recorded in NaCl (150 mM) with 41%. The maximum of root and shoot lengths were recorded in PEG (5%) and Ni (100μM) with 59 and 73 mm, respectively. Results showed that the maximum root and shoot fresh and dry weights were recorded at Ni (100μM) treatment. Understanding plant responses to environmental stresses can help select suitable plants in order to obtain sustainable products. Overall, we can conclude that under aforementioned treatments, the root growth of S. arvensis was more affected than the shoot growth.