Growth and physiological response of Kandelia obovata and Bruguiera sexangula seedlings to aluminum stress

Abstract

The role of mangroves as a biogeochemical buffer for heavy metal pollutants in coastal wetlands has been demonstrated, but knowledge gaps still exist on the tolerant capacity of mangroves to aluminum (Al). This study assessed the growth and physiological response of viviparous mangroves Kandelia obovata and Bruguiera sexangula to Al stress. The two mangrove seedlings were treated with AlCl3 at concentrations of 0 (as control) to 100 mmol L−1, and the impact of Al on their growth and antioxidant parameters were determined. Additionally, the accumulation and translocation of metal elements were estimated in B. sexangula seedlings under relative long-term Al stress. K. obovata appeared to survive with a tolerance potential of 10 mmol L−1 AlCl3, whereas B. sexangula had a higher tolerant ability of 50 mmol L−1 AlCl3. Both root elongation and seedling growth were inhibited by Al stress. The exposure to 25–100 mmol L−1 AlCl3 induced increases in membrane lipid peroxidation and osmoprotectant molecule (proline) in mangrove seedlings. Both mangrove seedlings revealed significant changes in antioxidant enzyme activities that were attributed to Al stress-induced oxidative damages. The activities of superoxide dismutase, catalase, peroxidase, and/or ascorbate peroxidase were differently impacted by the treatment time (7 days for short term versus 60 days for long term) and AlCl3 concentrations in K. obovata and B. sexangula seedlings. For B. sexangula seedlings, Al accumulation was in an order root > leaf > stem, whereas the translocation of metal elements in the aboveground tissues (leaf and stem) was differently impacted by Al stress. In conclusion, this study provides insights into different Al-tolerant abilities operated in two mangrove species that are widespread in coastal wetlands of China.

2,2′,4,4′-Tetrabromodiphenyl Ether (BDE-47) at Environmental Levels Influenced Photosynthesis in the Mangrove Species Kandelia obovata

“…It is the most common mangrove plant along the coastline in South China and can grow up to 3 m tall. Due to its wide distribution, important ecological functions, and the characteristics of the easy cultivation of its seedlings in the laboratory, K. obovate seedlings have become the subject of increasing research, with numerous studies exploring its various aspects [46][47][48][49]. Therefore, in this study, K. obovate seedlings were used to investigate the effects of BDE-47 at different environmental concentrations (0, 50, 500, and 5000 ng g-1 dw) on the stomatal characteristics and photosynthesis.…”

Metabolomic Study of Flavonoids in Camellia drupifera under Aluminum Stress by UPLC-MS/MS

“…Normally, aluminum (Al) exists in the form of insoluble silicates and aluminum oxides under neutral or moderately acidic soil conditions, but when the soil is eroded by acid rain or other factors that cause its pH to drop below 5.5, some of the insoluble aluminum will be leached and dissolved as Al 3+ , Al(OH) 2+ , and Al(OH) 2+ [ 5 , 6 ]. When in a free state, aluminum ions can be absorbed by plant roots, resulting in plants showing symptoms of aluminum toxicity [ 5 , 6 ], and their growth and normal metabolism are affected [ 7 , 8 ].…”

Physiological and Proteomic Changes in Camellia semiserrata in Response to Aluminum Stress

“…Compared to the content of metal cations (Mg 2+ , Ca 2+ , Na + , K + ), the content of protons (H + ) and strong acid anions (e.g., Cl − ) is higher in acidic soils; as a result, acid deposition is far greater than the soil's natural neutralizing capacity, and aluminum leaches in the soil solution. As a result of the leaching of aluminium from soil solutions, where some of the insoluble aluminium is dissolved as free Al 3+ , Al(OH) 2 + and Al(OH) 2+ , free aluminum ions can be absorbed by the plant root system and cause the plant to show symptoms of Al toxicity [7], affecting its growth and normal metabolism [8,9].…”