Effects of dormancy breaking methods on germination of Cercis siliquastrum and Spartium junceum and seedling growth

Abstract

Seed dormancy is a mechanism of long survival that is ecologically important for seed propagation and dispersal and the expansion of plant populations. The impermeability of the seed coat in the Fabaceae family is due to a layer of sclerotic cells. Two experiments were conducted to investigate the effect of different seed treatment on germination parameters and seedling growth in Cercis siliquastrum and Spartium junceum. Experimental treatments comprised of chemical and thermal scarification treatment consisting of boiling water (2, 5, 10 min), H₂SO ₄ (30, 60 min) and GA (0, 500 and 1,000 mg L⁻¹) in C. siliquastrum and boiling water (2, 5, 10 min), H₂SO ₄ (2, 5 min) in S. junceum. The results presented here indicate that chemical scarification by soaking in sulfuric acid for 30 min and 2 min in C. siliquastrum and S. junceum, respectively were the most efficient methods to breaking the seed dormancy. The application of these methods promoted the highest values of indices seedlings. In the light of the found results, it revealed that C. siliquastrum and S. junceum seeds are affected by a coat dormancy, which can be removed by a chemical-thermal scarification with sulfuric acid and boiling water. The data obtained contribute to a better comprehension of propagation and establishment of these shrubs ornamental by seedling.