Aluminum accumulation in mosses from the Brazilian savanna: a comparative study of two species revealing similar traits to vascular plants.

Main conclusion: Mosses from the Brazilian savanna accumulate aluminum (Al) and exhibit mechanisms similar to vascular plants, but different species use distinct strategies for Al accumulation in apoplast and symplast pathways. Bryophytes are conspicuous components of the vegetation in the Brazilian savanna, particularly in the Campo Rupestre phytophysiognomy. There are two main types of Campos Rupestres, each with distinct soil characteristics: quartzitic and ferruginous. Quartzite soils are typically acidic and nutrient-poor, while ferruginous soils are rich in iron and tend to be acidic and low in nutrients. Despite these distinctions, these ecosystems share high soil aluminum (Al) content and vegetation with many Al-tolerant vascular plant species. However, the relationship between Al and bryophytes remains unexplored. We found that Campylopus lamellatus Mont. (Dicranaceae) and Polytrichum juniperinum Hedw. (Polytrichaceae) accumulate Al, despite the differences in the histolocalization within the gametophyte. C. lamellatus tends to accumulate Al apoplastically in the cell walls, whereas P. juniperinum accumulates it symplastically, potentially in vacuoles and chloroplasts. Additionally, populations of the same moss species in different studied sites of Campos Rupestres exhibited a similar pattern of accumulation, as our data indicated the pH and Al content of the soils were comparable. Our study provides the first evidence of Al accumulation in mosses from the Brazilian savanna, highlighting the potential for bryophytes to adapt to high-aluminum environments similarly to vascular plants.