title: Metal (Pb, Zn and Cu) uptake and tolerance by mangroves in relation to root anatomy and lignification/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 anatomy and lignification/suberization on metal uptake and tolerance in seedlings of six species of mangroves. The results revealed that the three rhizophoraceous species (Bruguiera gymnorrhiza (L.) Poir, Kandelia obovata Sheue, Liu & Yong and Rhizophora stylosa Griff) consistently exhibited higher metal tolerances than the three pioneer species (Aegiceras corniculatum (Linn.) Blanco, Acanthus ilicifolius L. and Avicennia marina (Forsk.) Viern.). Moreover, metal-tolerant species often exhibited a thick exodermis with high lignification and suberization. The tolerance indices of the mangroves were found to be positively correlated with the amounts of lignin and suberin deposition within the exodermal cell walls. The observed metal uptake by the excised roots further illustrated that a lignified/suberized exodermis directly delayed the entry of metals into the roots, and thereby contributed to a higher tolerance to heavy metals. In summary, the present study proposes a barrier property of the lignified/suberized exodermis in dealing with the stresses of heavy metals, such that the mangroves which possessed more extensive lignification/suberization within the exodermis appeared to exhibit higher metal tolerance.
authors: 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: Hao
authors: H
authors: Cheng
authors: 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: Zhao-Yu
authors: ZY
authors: Jiang
authors: 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: Yong
authors: Y
authors: Liu
authors: State Key Laboratory for Bio-control, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.
authors: Zhi-Hong
authors: ZH
authors: Ye
authors: 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: Mei-Lin
authors: ML
authors: Wu
authors: 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: Cui-Ci
authors: CC
authors: Sun
authors: 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: Fu-Lin
authors: FL
authors: Sun
authors: 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: Jiao
authors: J
authors: Fei
authors: 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: You-Shao
authors: YS
authors: Wang
mesh_terms: D001692:Biological Transport; D002681:China; D003300:Copper / Q000378:metabolism*; D007854:Lead / Q000378:metabolism*; D008031:Lignin / Q000032:analysis / Q000378:metabolism; D008055:Lipids / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D018515:Plant Leaves / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology; D018517:Plant Roots / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology; D043982:Rhizophoraceae / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D036226:Seedlings / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology; D013045:Species Specificity; D053833:Wetlands; D015032:Zinc / Q000378:metabolism*
chemical_list: D008055:Lipids; D007854:Lead; D003300:Copper; C065875:suberin; D008031:Lignin; D015032:Zinc
keywords: exodermis; heavy metals; mangrove plants