Micropropagation of the Critically Endangered Silene conglomeratica Melzh.: A Tool for Conservation and Ornamental Aspects

This study provides a comprehensive and refined framework for the micropropagation of the critically endangered Greek endemic Silene conglomeratica. Using a limited seed stock, a reliable in vitro propagation protocol was developed, supporting both ex situ conservation and potential commercial applications in floriculture and landscape architecture. Nodal explants excised from aseptic seedlings, established on half-strength Murashige and Skoog (MS) medium, were successfully used for culture initiation. Supplementation with 1.0 mg L−1 meta-topolin (mT) and 0.2 mg L−1 1-naphthaleneacetic acid (NAA) promoted shoot proliferation. Subsequent subculturing on half-strength Rugini Olive Medium (OM/2) supplemented with 0.5 mg L−1 2-isopentenyladenine (2iP) resulted in high multiplication rates and a high frequency of spontaneous rooting. Rooting initiation was further optimized using OM/2 supplemented with 0.5 mg L−1 indole-3-butyric acid (IBA). The high acclimatization percentage (80%) confirms the feasibility of this protocol for ex situ conservation and highlights its applicability for nursery production and specialized landscape use. Overall, this study contributes an efficient and scalable propagation strategy that supports both the conservation and sustainable utilization of this valuable endemic species. Future work should focus on refining these protocols through more targeted testing of concentrations and alternative combinations of growth regulators and nutrient compositions.