The effects of petroleum contaminated soil on germination and morphophysiological characteristics of wheatgrass (Agropyron desertorum) for landscape design

Petroleum hydrocarbons as organic contaminants are among the materials that pollute the soil. These compounds and the resutant stress to plants limit selection of suitable species to be planted in hydrocarbon contaminated sites. The aim of this research was to determine the effects of petroleum compounds on germination and morphophysiological characteristics of wheatgrass (Agropyron desertorum). This research was carried out in a randomized complete block for germination experiment and split-plot design in time in randomized complete block for the second part of the experiment in three replications. Results of the first experiment showed that germination percentage، germination rate، mean day of germination and germination energy of wheatgrass had no significant differences between the control and 20% sludge treatment. The lowest germination percentage was observed in 80% sludge. In the second experiment (growth phase) higher growth rate was observed in 20% sludge، and no significant differences were observed in density، color، chlorophyll، proline and relative water content of these two treatments. The results showed that by increasing the level of sludge to 40% and 80%، density، color، growth and chlorophyll content increased but proline content decreased significantly. The difference between 40% and 80% sludge treatments was significant too. In conclusion، native species wheatgrass can germinate in low levels of petroleum contaminants in soil.