Mangrove plants play an important role in the remediation of heavy-metal-contaminated estuarine and coastal areas; Barringtonia racemosa is a typical semi-mangrove plant. However, the effect of heavy metal stress on this plant has not been explored. In this study, tolerance characteristics and the accumulation profile of cadmium (Cd) and lead (Pb) in B. racemosa were evaluated. The results indicated that B. racemosa exhibited a high tolerance in single Cd/Pb and Cd + Pb stress, with a significant increase in biomass yield in all treatment groups, a significant increase in plant height, leaf area, chlorophyll and carotenoid content in most treatment groups and without significant reduction of SOD, POD, MDA, proline content, Chl a, Chl b, Chl a + b, Car, ratio of Chl a:b and ratio of Car:Chl (a + b). Cd and Pb mainly accumulated in the root (≥93.43%) and the content of Cd and Pb in B. racemosa was root > stem > leaf. Pb showed antagonistic effects on the Cd accumulation in the roots and Cd showed antagonistic or synergistic effects on the Pb accumulation in the roots, which depended on the concentration of Cd and Pb. There was a significant synergistic effect of Cd and Pb enrichment under a low Cd and Pb concentration treatment. Thus, phytoremediation could potentially use B. racemosa for Cd and Pb.

This study evaluates the growth, survival pressures, and community dynamics of Barringtonia racemosa (L.) Spreng. populations in Jiulong Mountain and Suixi County, Guangdong Province. Six distinct plant communities were identified, with human disturbances significantly disrupting natural succession processes. The population in Jiulong Mountain, particularly within the Talipariti tiliaceum-B. racemosa community (JLS-T), experienced higher survival pressures compared to Suixi County. Interspecific competition varied, with species like Derris trifoliata, T. tiliaceum, and invasives such as Ipomoea cairica and Mikania micrantha exerting substantial pressure on B. racemosa. Analysis of 234 B. racemosa individuals revealed significant correlations between diameter at breast height (DBH), plant height, and age structure distribution, with a linear relationship between DBH and height underscoring their relevance in understanding wood volume, biomass, and stand structure. Survival pressures were inversely related to DBH, indicating reduced competition as trees matured. Growth patterns exhibited an age-dependent plateau in height, potentially influenced by environmental and anthropogenic factors. Management strategies should prioritize the growth of individuals with DBH less than 5 cm (age classes I ~ II). These findings underscore the need for targeted conservation efforts to protect B. racemosa communities and sustain wetland ecosystems.