Studies on Seed Germination and Micropropagation of Ebenus sibthorpii, an Endemic Shrub of Greece with Potential Ornamental Use

Abstract

The introduction of new ornamental species is a challenge for the floriculture industry. Ebenus sibthorpii is an endemic species of Greece, with a strong ornamental potential. To the best of our knowledge, there are no studies on the in vitro propagation of this species. Therefore, the current study aimed to determine the possibility of micropropagation of Ebenus sibthorpii as a first step for its introduction into the floriculture industry. A preliminary study on the germination ability of the species was also conducted on 1/2-strength Murashige and Skoog medium (MS/2), in the range of 5–35 °C. Seeds germinated at 46–64% indifferently of temperature between the range of 10–30 °C. In vitro cultures were successfully established (77–80% explant response) from single-node explants excised from seedlings, on MS medium either hormone-free (Hf) or supplemented with 6-benzyladenine (BA) at 0.5 and 1 mg L−1. The subsequent multiplication stage involved subcultures in MS medium either Hf or supplemented with various cytokinin types and concentrations, while the combination of 0.01 mg L−1 naphthaleneacetic acid (NAA) with BA was also tested. Τhe highest multiplication indices (3.6–4.6) were observed in media containing BA at 0.1–0.5 mg L−1, regardless of NAA presence, and in those with 0.5 mg L−1 ZEA or 1 mg L−1 TDZ. The highest number of shoots were formed in TDZ media, but almost half of them did not elongate. To address this, a two-fold culture was developed, where micro-shoots produced on TDZ media were transferred to Hf, MS or MS/2 medium to elongate. Thus, the highest multiplication index (16.4) was achieved when micro-shoots from 1 mg L−1 TDZ medium were transferred to MS medium. The present study could be the basis of further exploitation and conservation of E. sibthorpii.