In Vitro Seed and Clonal Propagation of the Mediterranean Bee Friendly Plant Anthyllis hermanniae L.

Abstract

Anthyllis hermanniae L. (Fabaceae) is a perennial Mediterranean shrub with the potential to be used as a bee-friendly ornamental plant in arid and semi-arid regions, valued for its tolerance of barren soils, winds, and strong temperature changes. With the aim of facilitating the introduction of the species into the horticulture industry, its in vitro seed and clonal propagation was investigated for the first time, to our knowledge. Seeds stored in the dark at room temperature for 4, 7, 9, 12, and 18 months germinated at percentages higher than 80% after scarification, when incubated in vitro in solid half-strength Murashige and Skoog (MS) medium at temperatures from 10 to 25 °C, while photoperiod (continuous darkness or 16 h light period/8 h dark) during incubation did not affect germination. Explants excised from in vitro grown seedlings established at higher percentages compared to explants from adult native plants, more efficiently in MS medium with 1.0 mg L−1 6 N benzyladenine (BA). During subcultures in the same medium, juvenile explants formed more and longer shoots than adult ones. Almost all adult explants formed shoots when subcultured in MS medium with 0.0 to 4.0 mg L−1 BA, zeatin, kinetin or 6-(γ,γ-dimethylallylamino)purine (2iP). ΒA at 0.5 to 2.0 mg L−1 induced many more shoots (17–21) per explant and much higher multiplication indices compared to all other cytokinins, while longer shoots were produced in a medium without hormones or with 0.5–1.0 mg L−1 2iP. Microshoots cultured in half-strength MS medium with 0.0–4.0 mg L−1 indole-3-butyric acid rooted at highest percentage (around 70%) in the medium containing 4.0 mg L−1 IBA, while microshoots of juvenile origin developed more and longer roots compared to adult ones. Micropropagated plantlets were successfully acclimatized ex vitro (>97%), regardless of their origin. The efficient micropropagation of A. hermaniae will facilitate its sustainable exploitation as a bee-friendly landscape plant, a forage plant for honeybees in Mediterranean areas, and a medicinal plant.