title: Pb uptake and tolerance in the two selected mangroves with different root lignification and suberization.
abstract: Metal pollution has been widely reported in mangrove wetlands; however, the mechanisms involved in metal detoxification by mangroves are still poorly understood. This study aimed to investigate the possible function of root lignification/suberization on Pb uptake and tolerance in mangroves. Two mangroves, Acanthus ilicifolius and Rhizophora stylosa with different root lignification/suberization were selected as plant materials; the former exhibits a thin exodermis and low lignification/suberization, while the latter possesses a thick exodermis and high lignification/suberization. A pot trial with addition of Pb was conducted to investigate the differences in Pb uptake and tolerance between the two mangroves. The experiment of rhizobox was designed to explore Pb dynamics and availabilities in the rhizosphere soils, besides, the ability of Pb uptake by the excised roots and X-ray analysis for Pb distribution within roots were also detected. The results revealed that R. stylosa exhibited relatively higher Pb tolerance together with less Pb accumulations when compared to A. ilicifolius. For both species, lower proportion of exchangeable and Carbonate Pb and higher higher Fe-Mn oxides Pb were observed in the rhizosphere zone when compared to the respective non-rhizosphere zone. The results from metal uptake by the excised roots and X-ray analysis clearly showed that the thick lignified/suberized exodermis of R. stylosa could more efficiently delay Pb entering into the roots, leading to less Pb accumulation. In summary, the present study proposes a barrier property of the lignified/suberized exodermis in dealing with the stresses of Pb.
authors.affiliation: State Key Laboratory of Tropical Oceanography and Daya Bay Marine Biology Research Station, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Tropical Oceanography and Daya Bay Marine Biology Research Station, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China. yswang@scsio.ac.cn.
authors.forename: You-Shao
authors.initials: YS
authors.lastname: Wang
authors.affiliation: Key Laboratory for Exploitation & Utilization of Marine Fisheries Resource in South China Sea, Ministry of Agriculture, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510300, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory for Bio-control, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006, China.
authors.forename: Zhi-Hong
authors.initials: ZH
authors.lastname: Ye
authors.affiliation: State Key Laboratory of Tropical Oceanography and Daya Bay Marine Biology Research Station, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.
authors.forename: Mei-Lin
authors.initials: ML
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Tropical Oceanography and Daya Bay Marine Biology Research Station, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.
authors.forename: Cui-Ci
authors.initials: CC
authors.lastname: Sun
mesh_terms: D027901:Acanthaceae / Q000033:anatomy & histology / Q000378:metabolism*; D007854:Lead / Q000378:metabolism*; D018517:Plant Roots / Q000033:anatomy & histology / Q000378:metabolism; D043982:Rhizophoraceae / Q000033:anatomy & histology / Q000378:metabolism*; D058441:Rhizosphere; D013045:Species Specificity; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D014934:Wood / Q000033:anatomy & histology
chemical_list: D014874:Water Pollutants, Chemical; D007854:Lead
keywords: Exodermis; Lignification/suberization; Mangrove; Pb; Root aeration