Saving the last populations of Strawberry Tree (Arbutus andrachne; Ericaceae) in the Republic of Georgia
Arbutus andrachne L. (Greek strawberry tree) is an evergreen shrub or small tree with a circum-Mediterranean distribution from Tunisia to Morocco along the north of Africa, and from Spain to Turkey along southern Europe. However, the more restricted Euro-Siberian populations, such as those in the Republic of Georgia, are considered endangered. Here, Arbutus andrachne occurs in small populations, sometimes within occupied or contested territory, and efforts to regenerate the species from Arbutus andrachne trees at the National Botanic Garden Georgia (Tblisi) have been largely unsuccessful. Although the seeds germinate readily, the seedlings fail to establish. In part, this issue may be linked to the presence and/or specificity of seedlings for certain mycorrhizal fungi. Like many other members of the Ericaceae, Arbutus species are dependent on mycorrhizal fungi for the acquisition of nutrients and water from the soil in exchange for host-derived carbon. A limited diversity or lack of compatible mycorrhizal fungi can significantly impede plant growth.
- In this project, the intern will examine the role of mycorrhizas in Arbutus plant establishment, and test the hypothesis that reduced fungal diversity and infectivity in native soils may have limited Arbutus seedling establishment. To test, this hypothesis, the intern will:
- Examine root samples of Arbutus andrachne collected from the National Botanic Garden Georgia (Tblisi) and Ajara (southwestern Georgia bordering Turkey) for the abundance and type(s) of mycorrhizal colonization**;
- Test mycorrhizal infectivity and effect on host plant growth using a bioassay (or trap) plant, and identify mycorrhizal fungi colonizing the root tips of the trap plants using DNA sequencing.
** We are exploring the possibility of sending the REU intern to Tblisi for soil and root collections. This will be subject to permission from the Republic of Georgia.