Work

Rainfall-driven metal resuspension triggers photosynthetic stress in Restinga vegetation

Year: 2026

Type: article

Abstract: Extreme rainfall events can remobilize contaminated sediments, increase metal bioavailability and trigger physiological stress in coastal vegetation. This is particularly relevant in mining-impacted areas such as the Rio Doce basin (Brazil), where contaminated sediments remain susceptible to resuspension. However, short-term plant responses to rainfall-driven metal dynamics are still poorly understood. This study investigated whether abiotic stress drives spatiotemporal responses or if adaptive strategies are species-specific. We analyzed chlorophyll a fluorescence (ChlF), leaf concentrations of As, Cd, Cr, and V, and bioaccumulation factors (BAFs) of Cu, Fe, Zn, and Mn in four coastal species across three phases of the 2020 rainy season. Herbaceous species showed higher concentrations of toxic elements, while tree species exhibited no significant variation. Rainfall pulses reduced elemental accumulation in shoots, particularly BAF_Fe in herbs and BAF_Mn in trees. Chlorophyll index (SPAD) and Normalized Difference Vegetation Index (NDVI) indicated negative effects on photosynthesis following heavy rainfall. Herbaceous plants showed temporary declines in photosystem stability and energy-use efficiency, alongside increased energy dissipation (DI 0 /RC), suggesting a protective response. In January 2020, energy dissipation increased by ~ 148% in Ipomoea pes-caprae and ~ 69% in Scaevola plumieri , while their performance index (PI ABS ) declined. In contrast, tree species ( Manilkara salzmannii and Protium heptaphyllum ) remained relatively stable. These findings reveal a functional gradient: herbaceous species show rapid but reversible stress responses, whereas tree species maintain functional stability under fluctuating conditions. Overall, the study demonstrates that rainfall-driven metal resuspension differentially influences plant groups, providing insights into species as diagnostic indicators of acute stress (herbs) and their long-term phytostabilization potential (trees), highlighting the distinct roles in ecosystem resilience.

Source: Discover Plants.

DOI: 10.1007/s44372-026-00984-4