Factors affecting the seed germination and seedling emergence of muskweed (Myagrum perfoliatum)

Myagrum perfoliatum is a noxious broad-leaved weed in western Iranian farming systems. A better understanding of the timing of seedling emergence would facilitate the development of better control strategies for this weed. Therefore, the objective of this study was to examine the effects of different factors on muskweed seed germination. Only 2.8% of the seeds of this species, which are encapsulated in siliques, germinated by, while the seeds that had been removed from the siliques had a 50% germination rate. The immersion of muskweed fruits in concentrated sulfuric acid for 110 min was the best treatment for promoting germination. Gibberellic acid stimulated the germination of the naked seeds by 29.1%, potassium nitrate (40 mmol L-1) increased the germination rate to 71%, while higher concentrations of potassium nitrate inhibited germination. The optimum germination temperature for the naked seeds was 20/10 degrees C (day/night) and light was not required for germination. No seedling emerged when the seeds were buried 6 cm deep. The seeds were sensitive to both osmotic and salinity stress, but they germinated to 46-49% over a pH range of 4-10. The results of this study revealed that the seeds of M. perfoliatum have physiological dormancy and that it is slowly broken via after-ripening. However, the fruit wall can prevent germination after physiological dormancy is broken. Thus, this species has the potential to form a persistent seed bank because of the presence of the fruit wall.