Assessment of Seed Morphological Characteristics and Optimization of Methods for Seed Germination and Growth of Prunus ulmifolia Franch.: An Endemic Ornamental Species from Central Asia

Prunus ulmifolia Franch. (Rosaceae Juss.) is a relict endemic species of Central Asia that is valued for ornamental horticulture and breeding programs. However, seed propagation is challenging because of deep physiological dormancy and low germination rates. We investigated seed morphology, viability, and methods to enhance germination using material from natural populations in the Dzhungarian Alatau, and introduced plants from the Almaty Botanical Gardens. Morphometric analysis of pyrenes revealed significant differences between natural and introduced plants. Introduction was associated with a 36.5% increase in pyrene mass, a 19.2% increase in length, changes in shape, and reduced density. Seed viability ranged from 90% to 95%, with a moisture content between 2.57% and 3.61%. Cold stratification produced contrasting germination responses, whereas scarification affected germination negatively. Seeds from the botanical gardens actively split their endocarps under laboratory conditions (93.8%), whereas natural seeds remained dormant until exposed to field conditions. The addition of plant growth stimulants showed limited correlation between laboratory and field germination. Among the tested stimulants, the amino acid stimulator Ribav-Extra at 1.0 mL·L –1 induced the greatest field germination (70%) and seedling height (8.0 cm), and exceeded gibberellic acid, brassinosteroid, and phenolic compounds. The developed protocol provides a basis for conservation efforts and sustainable cultivation of P. ulmifolia across sites.