A simple method of mechanical scarification to break seed dormancy in Viola odorata

AbstractsViola odorata, also known as sweet violet, is a valuable plant for its fragrance and medicinal properties, but the cultivation is hindered by poor seed germination due to dormancy. The dormancy of V. odorata mainly resulted from a hard seed coat, and various methods has been reported in breaking the seed dormancy. However, most engaged in corrosive chemicals and highly dependent on the variety, or a lack of uniformity when using sandpapers. This study presents a simple, effective mechanical scarification method using rat-tooth tweezers to gently nick the seed coat tip. This mechanical scarification significantly increased germination, reaching a 70% rate after eight weeks, while non-scarified seeds failed to germinate. Combining mechanical scarification with cold stratification further enhanced germination compared to room-temperature (RT) storage. Additionally, growth at 18 {degrees}C produced higher rates than at RT and the addition of gibberellic acid (GA3) in the media promoted both germination and seedling growth, accompanied by increased water uptake. These findings propose a combination of mechanical scarification, cold stratification, and optimal GA3 treatment as a reliable, broadly applicable strategy for breaking dormancy and facilitating large-scale propagation and breeding of V. odorata.