Does seed modification and nitrogen addition affect seed germination of Pulsatilla grandis?

Abstract

Abstract Pulsatilla grandis is an endangered species in the Czech Republic and is protected in whole Europe because the number of its populations is declining. One of the possible causes is the deposition of atmospheric nitrogen. In our research, we investigated how nitrogen concentrations and seed appendage removal directly affect the species’ seed germination.Seeds were allowed to germinate under laboratory conditions in water solutions of NH4NO3 ranging in concentration from 0 to 4239 mg N l-1. They were able to germinate up to the concentration of 848 mg N l-1 even when covered with mycelium, which supports the idea that they can tolerate being strongly infected by fungi. We also found a significant positive effect of seed appendage removal on seed germination. Seeds without appendages germinated, on the average, with 11% greater probability, compared to seeds with appendages. We conclude that the germination of P. grandis is not directly affected by high N concentrations in rain water, which can range from 10 to 13 mg N l-1 near large cities. Surprisingly, low concentrations of N (up to 34 mg N l-1) might even slightly support the seed germination of P. grandis. The negative effect of N deposition on seeds is indirect and acts in conjunction with the absence of management at localities.