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Wu D, Li L, Li C, Dun B, Zhang J, Li T, Zhou C, Tan D, Yang C, Huang G, Zhang X. Apoplastic histochemical features of plant root walls that may facilitate ion uptake and retention. Open Life Sci 2022; 16:1347-1356. [PMID: 35071769 PMCID: PMC8749128 DOI: 10.1515/biol-2021-0137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 10/28/2021] [Accepted: 11/07/2021] [Indexed: 11/18/2022] Open
Abstract
We used brightfield and epifluorescence microscopy, as well as permeability tests, to investigate the apoplastic histochemical features of plant roots associated with ion hyperaccumulation, invasion, and tolerance of oligotrophic conditions. In hyperaccumulator species with a hypodermis (exodermis absent), ions penetrated the root apex, including the root cap. By contrast, in non-hyperaccumulator species possessing an exodermis, ions did not penetrate the root cap. In vivo, the lignified hypodermis blocked the entry of ions into the cortex, while root exodermis absorbed ions and restricted them to the cortex. The roots of the hyperaccumulators Pteris vittata and Cardamine hupingshanensis, as well as the aquatic invasives Alternanthera philoxeroides, Eichhornia crassipes, and Pistia stratiotes, contained lignin and pectins. These compounds may trap and store ions before hypodermis maturation, facilitating ion hyperaccumulation and retention in the apoplastic spaces of the roots. These apoplastic histochemical features were consistent with certain species-specific characters, including ion hyperaccumulation, invasive behaviors in aquatic environments, or tolerance of oligotrophic conditions. We suggest that apoplastic histochemical features of the root may act as invasion mechanisms, allowing these invasive aquatic plants to outcompete indigenous plants for ions.
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Affiliation(s)
- Di Wu
- Rare Plants Research Institute of Yangtze River, China Three Gorges Corporation, Yichang, Hubei, 443000, China
| | - Linbao Li
- Rare Plants Research Institute of Yangtze River, China Three Gorges Corporation, Yichang, Hubei, 443000, China
| | - Chengdao Li
- Rare Plants Research Institute of Yangtze River, China Three Gorges Corporation, Yichang, Hubei, 443000, China
| | - Bicheng Dun
- Rare Plants Research Institute of Yangtze River, China Three Gorges Corporation, Yichang, Hubei, 443000, China
| | - Jun Zhang
- Rare Plants Research Institute of Yangtze River, China Three Gorges Corporation, Yichang, Hubei, 443000, China
| | - Ten Li
- Engineering Research Center of Ecology and Agriculture Use of Wetland, Ministry of Education, and Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, Hubei 434025, China
| | - Cunyu Zhou
- Engineering Research Center of Ecology and Agriculture Use of Wetland, Ministry of Education, and Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, Hubei 434025, China
| | - Debao Tan
- Changjiang River Scientific Research Institute, Wuhan, Hubei 430010, China
| | - Chaodong Yang
- Engineering Research Center of Ecology and Agriculture Use of Wetland, Ministry of Education, and Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, Hubei 434025, China
| | - Guiyun Huang
- Rare Plants Research Institute of Yangtze River, China Three Gorges Corporation, Yichang, Hubei, 443000, China
| | - Xia Zhang
- Engineering Research Center of Ecology and Agriculture Use of Wetland, Ministry of Education, and Hubei Key Laboratory of Waterlogging Disaster and Agricultural Use of Wetland, Yangtze University, Jingzhou, Hubei 434025, China
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Guo X, Luo J, Du Y, Li J, Liu Y, Liang Y, Li T. Coordination between root cell wall thickening and pectin modification is involved in cadmium accumulation in Sedum alfredii. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 268:115665. [PMID: 33010543 DOI: 10.1016/j.envpol.2020.115665] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/17/2020] [Accepted: 09/12/2020] [Indexed: 06/11/2023]
Abstract
Root cell wall (RCW) modification is a widespread important defense strategy of plant to cope with trace metals. However, mechanisms underlying its remolding in cadmium (Cd) accumulation are still lacking in hyperaccumulators. In this study, changes of RCW structures and components between nonhyperaccumulating ecotype (NHE) and hyperaccumulating ecotype (HE) of Sedum alfredii were investigated simultaneously. Under 25 μM Cd treatment, RCW thickness of NHE is nearly 2 folds than that of HE and the thickened cell wall of NHE was enriched in low-methylated pectin, leading to more Cd trapped in roots tightly. In the opposite, large amounts of high-methylated pectin were assembled around RCW of HE with Cd supply, in this way, HE S. alfredii decreased its root fixation of Cd and enhanced Cd migration into xylem. TEM and AFM results further confirmed that thickened cell wall was caused by the increased amounts of cellulose and lignin while root tip lignification was resulted from variations of sinapyl (S) and guaiacyl (G) monomers. Overall, thickened cell wall and methylated pectin have synchronicity in spatial location of roots, and their coordination contributed to Cd accumulation in S. alfredii.
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Affiliation(s)
- Xinyu Guo
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Jipeng Luo
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yilin Du
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Jinxing Li
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yuankun Liu
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yongchao Liang
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Tingqiang Li
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou, 310058, China; National Demonstration Center for Experimental Environment and Resources Education, Zhejiang University, Hangzhou, 310058, China.
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