Some physical, chemical, and germination properties of Peganum harmala L. seeds

In this study, the aim was to determine some physical and chemical properties of the seeds of Peganum harmala, known as rue or harmel, and to determine the effects of some implementations to break the seed dormancy. The mean length, width, thickness, and surface area values for the P. harmala seeds were 4.78 mm, 1.81 mm, 1.53 mm, and 14.14 mm², respectively. Linked to the dimensions, the arithmetic mean diameter, geometric mean diameter, and sphericity values were calculated as 2.71 mm, 2.34 mm, and 0.50. The bulk density and true density values were measured as 0.5379 and 1.015 g cm⁻³, respectively, and the porosity value calculated linked to these values was 46.98%. The static friction angles on two different surfaces of galvanized metal and polyvinyl chloride (PVC) were measured as 15.67° and 17.67°, and the static friction coefficient values linked to these angles were 0.28 for galvanized metal and 0.32 for PVC. Terminal velocity experiments determined the velocity for P. harmala seeds was 5.03 ms⁻¹. According to analysis results for the chemical structure of P. harmala, dry matter ratio was 89.7%, crude ash ratio was 11.0%, crude protein was 10.3%, crude fiber was 42.0%, and crude oil ratio was 10.8%. In seed dormancy studies, the effects of sulfuric acid, precooling, soaking in water, and mechanical scarification (sanding) applications were determined. Accordingly, the most effective method for germination of P. harmala seeds was sanding with 84.0% germination rate. This was followed by soaking in water (78.0%) and 5 min H₂SO₄ (75.0%) applications. PRACTICAL APPLICATIONS: Turkey is a country with a current account deficit in the seed import–export balance. Therefore, the efficient use of seeds in each step of farming and postharvest operations is essential to reduce the seed waste. Determining the engineering properties of seeds will help to provide more efficient systems. The physical properties of seeds are important to design, develop, and adjustment of planters, storage structures, transporting systems, and postharvest systems. Chemical properties are essential to determine the optimum storage conditions and postharvest chemical processes for optimum utilization of seeds as foods or as raw materials for medicinal and industrial purposes. Seed dormancy‐breaking features will be useful to determine optimum presowing conditions and breeding conditions of the seeds.