Arbuscular mycorrhizae increase but vermicompost decrease the sun protection factor (SPF) in leaves of Hymenaea martiana Hayne seedlings

This study aimed to select the most efficient combination of arbuscular mycorrhizal fungi (AMF) and substrate to increase the photoprotective and in vitro antioxidant activities in Hymenaea martiana Hayne leaves. Hymenaea martiana seedlings were grown in soil with or without 10% vermicompost and inoculated with three AMF species: Acaulospora longula, Gigaspora albida, and Claroideoglomus etunicatum. Seedlings grown in soil without vermicompost or AMF inoculation served as controls. After 148 days of growth in a greenhouse, the photoprotective and antioxidant activities, and the production of some phenolics in the leaves were evaluated. Vermicompost supplementation reduced the photoprotective and antioxidant effects in extracts compared to the control. However regardless of the vermicompost treatment, mycorrhizal colonization resulted in a 40% increase in photoprotective activity compared to control; this enhancement was correlated with the increased concentration of proanthocyanidins in mycorrhizal plants. AMF inoculation improves the quality of H. martiana phytomass, dispensing the application of vermicompost in the cultivation substrate. This is the first report on the potential of AMF and vermicompost to increase the sun protection factor in H. martiana leaves.