Methods of breaking physical dormancy in seeds of the invasive weed Mimosa pudica (Fabaceae) and a comparison with 36 other species in the genus

The herbaceous legume Mimosa pudica is an invasive weed in many tropical and subtropical regions, as a serious problem for farmers since it is difficult to clear by hand. Moreover, it has water impermeable seeds, i.e. physical dormancy (PY), which could persist longer in the soil seed bank than non-dormant seeds, making big challenge in weed control. The aim of this study were to test the effect of various methods known to break PY in seeds of M. pudica, to identify the site(s) of water entry into seeds of M. pudica and also compare results of dormancy-breaking methods for seeds of M. pudica with those of 36 other species of Mimosa reported in the literature. Mechanical scarification, wet heat and cycles of wet heat and ice water effectively broke PY. Following wet heat at 80 ˚C for 10 min, water uptake was via the hilar region but not the pleurogram. Since PY has been reported in 36 species of Mimosa tested that includes invasive, rare and endemic species, it seems obvious that this kind of dormancy is not the cause of weediness in M. pudica. Further, the 36 species represent four of the five taxonomic sections of Mimosa, and thus it is likely that seeds of most of all of the about 500 species in the genus have PY.