Arbuscular mycorrhizal responsiveness of a Canary Island endemic (Artemisia thuscula Cav.): implications for nursery propagation and restoration

Arbuscular mycorrhizal fungi (AMF) influence plant establishment and nutrient balance, yet their role in insular endemics remains poorly understood. In this work, it was assessed field AM colonization and edaphic-foliar context in three Artemisia taxa from the Canary Islands ( A. thuscula Cav. and A. ramosa C. Sm. Ex Link. (endemic), and A. reptans C. Sm. (native, Vulnerable), and tested early mycorrhizal responsiveness of A. thuscula Cav. in nursery conditions after inoculation with Funneliformis mosseae (T.H. Nicolson & Gerd.), using A. annua L. as a reference. Field colonization varied strongly among sites: A. thuscula Cav. on the southern slope of Tenerife island showed the highest colonization (44%), linked to sandy, organic-rich soils, whereas northern and coastal populations had low values in finer, saline substrates. Foliar nutrients mirrored these contrasts, particularly for potassium, sodium and iron. In the nursery, AM inoculation enhanced seedling biomass (+ 93%) and foliar nitrogen and potassium, even though root colonization at lifting was low (3%), indicating strong responsiveness but weak dependence. These results identify A. thuscula Cav. as a facultatively mycotrophic endemic with high early responsiveness to AMF, supporting its integration into propagation and restoration of Macaronesian flora.