Germination rate of stinkwort (Dittrichia graveolens) and false yellowhead (D. viscosa) in relation to salinity

This study was conducted to investigate the effect of salinity on germination rate of stinkwort (Dittrichia graveolens (L.) Greuter) and false yellowhead (D. viscosa (L.) Greuter). Lettuce (Lactuca sativa L.) was used as a positive control. Seeds of all three test species were sown on agar plates with three different NaCl treatments (2.5 g NaCl/L ≈ 42 mM NaCl, 5 g NaCl/L ≈ 85 mM NaCl and 10 g NaCl/L ≈ 171 mM NaCl) and control treatment without NaCl. The three tested species germinated under all salinity conditions. However, they thrived best under control conditions and their germination rate was gradually declining with increasing salinity. Additionally, the start of their germination was delayed with increasing NaCl concentration. According to our findings, we can conclude that both Dittrichia species are very tolerant to salinity.