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Wang S, Liu J, Liu Y, Tian C. Application of rhizobium inoculation in regulating heavy metals in legumes: A meta-analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 945:173923. [PMID: 38880144 DOI: 10.1016/j.scitotenv.2024.173923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/21/2024] [Accepted: 06/09/2024] [Indexed: 06/18/2024]
Abstract
Rhizobium inoculation has been widely applied to alleviate heavy metal (HM) stress in legumes grown in contaminated soils, but it has generated inconsistent results with regard to HM accumulation in plant tissues. Here, we conducted a meta-analysis to assess the performance of Rhizobium inoculation for regulating HM in legumes and reveal the general influencing factors and processes. The meta-analysis showed that Rhizobium inoculation in legumes primarily increased the total HM uptake by stimulating plant biomass growth rather than HM phytoavailability. Inoculation had no significant effect on the average shoot HM concentration (p > 0.05); however, it significantly increased root HM uptake by 61 % and root HM concentration by 7 % (p < 0.05), indicating safe agricultural production while facilitating HM phytostabilisation. Inoculation decreased shoot HM concentrations and increased root HM uptake in Vicia, Medicago and Glycine, whereas it increased shoot HM concentrations in Sulla, Cicer and Vigna. The effects of inoculation on shoot biomass were suppressed by nitrogen fertiliser and native microorganisms, and the effect on shoot HM concentration was enhanced by high soil pH, organic matter content, and phosphorous content. Inoculation-boosted shoot nutrient concentration was positively correlated with increased shoot biomass, whereas the changes in pH and organic matter content were insufficient to significantly affect accumulation outcomes. Nitrogen content changes in the soil were positively correlated with changes in root HM concentration and uptake, whereas nitrogen translocation changes in the tissues were positively correlated with changes in HM translocation. Phosphorus solubilisation could improve HM phytoavailability at the expense of slight biomass promotion. These results suggest that the diverse growth-promoting characteristics of Rhizobia influence the trade-off between biomass-HM phytoavailability and HM translocation, impacting HM accumulation outcomes. Our findings can assist in optimising the utilisation of legume-Rhizobium systems in HM-contaminated soils.
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Affiliation(s)
- Shiqi Wang
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences (CAS), Urumqi 830011, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinbiao Liu
- Agricultural College, Heilongjiang Bayi Agricultural University, Daqing 163317, China
| | - Yalan Liu
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences (CAS), Urumqi 830011, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Changyan Tian
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences (CAS), Urumqi 830011, China.
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Cai Z, Yu T, Tan W, Zhou Q, Liu L, Nian H, Lian T. GmAMT2.1/2.2-dependent ammonium nitrogen and metabolites shape rhizosphere microbiome assembly to mitigate cadmium toxicity. NPJ Biofilms Microbiomes 2024; 10:60. [PMID: 39043687 PMCID: PMC11266425 DOI: 10.1038/s41522-024-00532-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 07/12/2024] [Indexed: 07/25/2024] Open
Abstract
Cadmium (Cd), a heavy metal, is negatively associated with plant growth. AMT (ammonium transporter) genes can confer Cd resistance and enhance nitrogen (N) uptake in soybeans. The potential of AMT genes to alleviate Cd toxicity by modulating rhizosphere microbiota remains unkonwn. Here, the rhizosphere microbial taxonomic and metabolic differences in three genotypes, i.e., double knockout and overexpression lines and wild type, were identified. The results showed that GmAMT2.1/2.2 genes could induce soybean to recruit beneficial microorganisms, such as Tumebacillus, Alicyclobacillus, and Penicillium, by altering metabolites. The bacterial, fungal, and cross-kingdom synthetic microbial communities (SynComs) formed by these microorganisms can help soybean resist Cd toxicity. The mechanisms by which SynComs help soybeans resist Cd stress include reducing Cd content, increasing ammonium (NH4+-N) uptake and regulating specific functional genes in soybeans. Overall, this study provides valuable insights for the developing microbial formulations that enhance Cd resistance in sustainable agriculture.
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Affiliation(s)
- Zhandong Cai
- South China Institute for Soybean Innovation Research, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Provincial Key Laboratory of Utilization and Conservation of Food and Medicinal Resources in Northern Region, Shaoguan University, Shaoguan, 512000, China
| | - Taobing Yu
- South China Institute for Soybean Innovation Research, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China
| | - Weiyi Tan
- South China Institute for Soybean Innovation Research, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Provincial Key Laboratory of Utilization and Conservation of Food and Medicinal Resources in Northern Region, Shaoguan University, Shaoguan, 512000, China
- Guangdong Provincial Key Laboratory for the Development Biology and Environmental Adaptation of Agricultural Organisms, South China Agricultural University, Guangzhou, Guangdong, China
- Key Laboratory for Enhancing Resource Use Efficiency of Crops in South China, Ministry of Agriculture and Rural Affairs, South China Agricultural University, Guangzhou, Guangdong, China
| | - Qianghua Zhou
- South China Institute for Soybean Innovation Research, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China
| | - Lingrui Liu
- South China Institute for Soybean Innovation Research, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China
| | - Hai Nian
- South China Institute for Soybean Innovation Research, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China.
- Guangdong Provincial Key Laboratory of Utilization and Conservation of Food and Medicinal Resources in Northern Region, Shaoguan University, Shaoguan, 512000, China.
- Guangdong Provincial Key Laboratory for the Development Biology and Environmental Adaptation of Agricultural Organisms, South China Agricultural University, Guangzhou, Guangdong, China.
- Key Laboratory for Enhancing Resource Use Efficiency of Crops in South China, Ministry of Agriculture and Rural Affairs, South China Agricultural University, Guangzhou, Guangdong, China.
| | - Tengxiang Lian
- South China Institute for Soybean Innovation Research, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China.
- Guangdong Provincial Key Laboratory of Utilization and Conservation of Food and Medicinal Resources in Northern Region, Shaoguan University, Shaoguan, 512000, China.
- Guangdong Provincial Key Laboratory for the Development Biology and Environmental Adaptation of Agricultural Organisms, South China Agricultural University, Guangzhou, Guangdong, China.
- Key Laboratory for Enhancing Resource Use Efficiency of Crops in South China, Ministry of Agriculture and Rural Affairs, South China Agricultural University, Guangzhou, Guangdong, China.
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Naciri R, Chtouki M, Oukarroum A. Mechanisms of cadmium mitigation in tomato plants under orthophosphate and polyphosphate fertilization regimes. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 274:116219. [PMID: 38492483 DOI: 10.1016/j.ecoenv.2024.116219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 03/06/2024] [Accepted: 03/13/2024] [Indexed: 03/18/2024]
Abstract
Cadmium (Cd) is one of the most toxic elements in soil, affecting morphological, physiological, and biochemical processes in plants. Mineral plant nutrition was tested as an effective approach to mitigate Cd stress in several crop species. In this regard, the present study aimed to elucidate how different phosphorus (P) fertilization regimes can improve some bio-physiological processes in tomato plants exposed to Cd stress. In a hydroponic experiment, the impact of two phosphorus fertilizer forms (Polyphosphate (poly-P): condensed P-form with 100% polymerization rate and orthophosphate (ortho-P): from orthophosphoric acid) on the photosynthetic activity, plant growth, and nutrient uptake was assessed under three levels of Cd stress (0, 12, and 25 µM of CdCl2). The obtained results confirmed the negative effects of Cd stress on the chlorophyll content and the efficiency of the photosynthesis machinery. The application of poly-P fertilizer significantly improved the chlorophyll stability index (82%) under medium Cd stress (Cd12), as compared to the ortho-P form (55%). The analysis of the chlorophyll α fluorescence transient curve revealed that the amplitude of Cd effect on the different steps of electron transfer between PSII and PSI was significantly reduced under the poly-P fertilization regime compared to ortho-P, especially under Cd12. The evaluation of the RE0/RC parameter showed that the electron flux reducing end electron acceptors at the PSI acceptor side per reaction center was significantly improved in the poly-P treatment by 42% under Cd12 compared to the ortho-P treatment. Moreover, the use of poly-P fertilizer enhanced iron uptake and its stoichiometric homeostasis in the shoot tissue which maintained an adequate absorption of iron under Cd stress conditions. Findings from this study revealed for the first time that inorganic polyphosphate fertilizers can reduce Cd toxicity in tomato plants by enhancing photosynthesis activity, nutrient uptake, plant growth, and biomass accumulation despite the high level of cadmium accumulation in shoot tissues.
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Affiliation(s)
- Rachida Naciri
- Plant Stress Physiology Laboratory, College of Agriculture and Environmental Sciences, Mohammed VI Polytechnic University, Benguerir, Morocco.
| | - Mohamed Chtouki
- Plant Stress Physiology Laboratory, College of Agriculture and Environmental Sciences, Mohammed VI Polytechnic University, Benguerir, Morocco
| | - Abdallah Oukarroum
- Plant Stress Physiology Laboratory, College of Agriculture and Environmental Sciences, Mohammed VI Polytechnic University, Benguerir, Morocco
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Song L, Zhou J, Xu X, Na M, Xu S, Huang Y, Zhang J, Li X, Zheng X. Inoculation of cadmium-tolerant bacteria to regulate microbial activity and key bacterial population in cadmium-contaminated soils during bioremediation. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 271:115957. [PMID: 38219617 DOI: 10.1016/j.ecoenv.2024.115957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/30/2023] [Accepted: 01/06/2024] [Indexed: 01/16/2024]
Abstract
The perennial ryegrass Lolium perenne can be used in conjunction with cadmium (Cd)-tolerant bacteria such as Cdq4-2 (Enterococcus spp.) for bioremediation of Cd-contaminated soil. In this study, a theoretical basis was provided to increase the efficiency of L. perenne remediation of Cd-contaminated soil using microorganisms to maintain the stability of the soil microbiome. The experimental design involved three treatment groups: CK (soil without Cd addition) as the control, 20 mg·kg-1 Cd-contaminated soil, and 20 mg·kg-1 Cd-contaminated soil + Cdq4-2, all planted with L. perenne. The soil was collected on day 60 to determine the soil microbial activity and bacterial community structure and to analyze the correlation between soil variables, the bacterial community, available Cd content in the soil, Cd accumulation, and L. perenne growth. The soil microbial activity and bacterial community diversity decreased under Cd stress, and the soil microbial community composition was changed; while inoculation with Cdq4-2 significantly increased soil basal respiration and the activities of urease, invertase, and fluorescein diacetate (FDA) hydrolase by 83.65%, 79.72%, 19.88%, and 96.15% respectively; and the stability of the community structure was also enhanced. The Actinobacteriota biomass, the amount of available Cd, and the above- and belowground Cd content of L. perenne were significantly negatively correlated with the total phosphorus, total potassium, and pH. The activity of urease, invertase, and FDA hydrolase were significantly positively correlated with the biomasses of Acidobacteriota and L. perenne and significantly negatively correlated with the Chloroflexi biomass. Further, the available soil Cd content and the above- and belowground Cd levels of L. perenne were significantly positively correlated with the Actinobacteriota biomass and significantly negatively correlated with the Gemmatimonadetes biomass. Overall, inoculating Cd-tolerant bacteria improved the microbial activity, diversity, and abundance, and changed the microbial community composition, facilitating the remediation of Cd-contaminated soil by L. perenne.
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Affiliation(s)
- Lanping Song
- Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded by Anhui Province and Ministry of Education, School of Ecology and Environment, Anhui Normal University, Wuhu 241002, China
| | - Jihai Zhou
- Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded by Anhui Province and Ministry of Education, School of Ecology and Environment, Anhui Normal University, Wuhu 241002, China; Collaborative Innovation Center of Southern Modern Forestry, Nanjing Forestry University, Nanjing 210037, China.
| | - Xiaoyang Xu
- Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded by Anhui Province and Ministry of Education, School of Ecology and Environment, Anhui Normal University, Wuhu 241002, China
| | - Meng Na
- Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded by Anhui Province and Ministry of Education, School of Ecology and Environment, Anhui Normal University, Wuhu 241002, China
| | - Shangqi Xu
- Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded by Anhui Province and Ministry of Education, School of Ecology and Environment, Anhui Normal University, Wuhu 241002, China
| | - Yongjie Huang
- Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded by Anhui Province and Ministry of Education, School of Ecology and Environment, Anhui Normal University, Wuhu 241002, China
| | - Jie Zhang
- Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded by Anhui Province and Ministry of Education, School of Ecology and Environment, Anhui Normal University, Wuhu 241002, China
| | - Xiaoping Li
- Collaborative Innovation Center of Southern Modern Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Xianqing Zheng
- Institute of Eco-Environment and Plant Protection, Shanghai Academy of Agricultural Sciences, Shanghai 201403, China.
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5
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Chen X, Wu X, Han C, Jia Y, Wan X, Liu Q, He F, Zhang F. A WRKY transcription factor, PyWRKY71, increased the activities of antioxidant enzymes and promoted the accumulation of cadmium in poplar. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 205:108163. [PMID: 37979573 DOI: 10.1016/j.plaphy.2023.108163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/28/2023] [Accepted: 11/02/2023] [Indexed: 11/20/2023]
Abstract
Cadmium (Cd) pollution poses significant threats to the ecological environment and human health. Currently, phytoremediation is recognized as an environmentally friendly approach for mitigating Cd pollution, with increasing attention on the utilization of transgenic plants in Cd-contaminated soil remediation. In this study, we isolated and cloned PyWRKY71 from Populus yunnanensis and conducted a pot experiment to validate its enhanced functionality in conferring Cd tolerance to woody plants (poplar). During the experiment, the increase in plant height of the OE-87 line (overexpression poplar) was 1.46 times than that of the wild type (WT). Moreover, PyWRKY71 significantly promoted the accumulation of Cd in poplar, especially in the roots, where the Cd content in the OE-45 and OE-87 lines was 1.42 times than that in the WT. The chlorophyll content of transgenic poplar leaves was higher than that of the WT, reflecting a protective mechanism of PyWRKY71. Additionally, the activities of other antioxidants, including POD, SOD, CAT, and MDA, were elevated in transgenic poplars, bolstering their tolerance to Cd stress. In summary, PyWRKY71 exhibits substantial potential in regulating plant tolerance to Cd stress. This study not only provides a solid scientific foundation but also introduces a novel modified poplar variety for the remediation of Cd pollution.
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Affiliation(s)
- Xiaoxi Chen
- College of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Xiaolu Wu
- College of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China; China Construction Eighth Engineering Bureau Co., Ltd. Southwest Branch, China
| | - Chengyu Han
- College of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Yuhang Jia
- College of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Xueqin Wan
- College of Forestry, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Qinglin Liu
- College of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Fang He
- College of Forestry, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Fan Zhang
- College of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China.
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6
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Chen A, Liu T, Deng Y, Xiao R, Zhang T, Wang Y, Yang Y, Lakshmanan P, Shi X, Zhang F, Chen X. Nitrate _dependent suberization regulates cadmium uptake and accumulation in maize. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 878:162848. [PMID: 36931522 DOI: 10.1016/j.scitotenv.2023.162848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/14/2023] [Accepted: 03/09/2023] [Indexed: 05/13/2023]
Abstract
In this study, effect of nitrate-dependent suberization in maize root on cadmium (Cd) uptake and accumulation was investigated. Suberization in maize roots was significantly lower in plants grown with a high nitrate supply compared with low nitrate. This decrease was seen in the total amount of suberin, in which the aliphatic suberin amount was significantly decreased, whereas no difference in aromatic suberin content between different N-treatments. RNA-sequencing showed that suberin biosynthesis genes were upregulated in low nitrate treatment, which correlated well with the increased suberin content. Bioimaging and xylem sap analysis showed that reduced exodermal and endodermal suberization in roots of plants grown under high nitrate promoted radial Cd transport along the crown root. The enhanced suberization in crown roots of plants grown in low nitrate restricted the radial transport of Cd from epidermis to cortex via decreased accessibility to Cd related transporters at the plasmalemma. Also, under low nitrate supply, the Cd transport gene ZmNramp5 was upregulated in the crown root, which may enhance Cd uptake by root tip where exodermis and endodermis were not fully suberized. These results suggest that high nitrate supply enhances Cd uptake and radial transport in maize roots by reducing exodermal and endodermal suberization.
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Affiliation(s)
- Anle Chen
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China; Key Laboratory of Low-carbon Green Agriculture in Southwestern China, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing 400716, China
| | - Tong Liu
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China; Key Laboratory of Low-carbon Green Agriculture in Southwestern China, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing 400716, China
| | - Yan Deng
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Ran Xiao
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Tong Zhang
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Yuan Wang
- Key Laboratory of Low-carbon Green Agriculture in Southwestern China, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing 400716, China
| | - Yuheng Yang
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China; College of Plant Protection, Southwest University, Chongqing 400715, China
| | - Prakash Lakshmanan
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China; Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning 530007, China; Queensland Alliance for Agriculture and Food Innovation, University of Queensland, St Lucia 4067, QLD, Australia
| | - Xiaojun Shi
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Fusuo Zhang
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China; College of Resources and Environmental Sciences, National Academy of Agriculture Green Development, Key Laboratory of Plant-Soil Interactions, China Agricultural University, Beijing 100193, China.
| | - Xinping Chen
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China; Key Laboratory of Low-carbon Green Agriculture in Southwestern China, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing 400716, China.
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Shen S, Li Y, Chen M, Huang J, Liu F, Xie S, Kong L, Pan Y. Reduced cadmium toxicity in rapeseed via alteration of root properties and accelerated plant growth by a nitrogen-fixing bacterium. JOURNAL OF HAZARDOUS MATERIALS 2023; 449:131040. [PMID: 36821906 DOI: 10.1016/j.jhazmat.2023.131040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 02/09/2023] [Accepted: 02/17/2023] [Indexed: 06/18/2023]
Abstract
Cd accumulation in crops has become a global environmental problem because it endangers human health. Screening for microorganisms that can reduce Cd accumulation in crops is a possible measure to address this issue. However, success has been limited, and most previous work did not involve bacteria. In the present study, a strain of N-fixing bacteria (Burkholderia spp.) that exhibits high levels of Cd tolerance was screened. The ability of this bacterium to reduce Cd in rapeseed was then assessed in sterile hydroponic and open soil culture systems. In the hydroponic system, the Burkholderia inoculum promoted Cd fixation in rapeseed roots and thus reduced Cd enrichment in aboveground edible tissues (leaves). The mechanisms were related to increased activity of pectin methylesterase in root cell walls, and the transformation of the chemical form of root Cd from "active" (NaCl-extracted) to "inert" (HCl-extracted and residual Cd) states. Additionally, Burkholderia accelerated plant growth, thus shortening the period in which the plant is available for Cd absorption. In the soil culture system, Burkholderia also reduced Cd enrichment in rapeseed leaves in the presence of other microorganisms. Thus, the bacterial strain shows potential for broad application for reducing the accumulation of Cd in crops.
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Affiliation(s)
- Shili Shen
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650091, Yunnan, China; Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China; School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China
| | - Yinghan Li
- School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China
| | - Mingbiao Chen
- School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China; Instititue of International Rivers and Eco-security, Yunnan Key Laboratory of International Rivers and Trans-Boundary Eco-security, Yunnan University, Kunming 650091, China
| | - Juan Huang
- Instititue of International Rivers and Eco-security, Yunnan Key Laboratory of International Rivers and Trans-Boundary Eco-security, Yunnan University, Kunming 650091, China
| | - Feng Liu
- Wuzhou Agricultural Products Quality and Safety Comprehensive Testing Center, Wuzhou 543000, Guangxi, China
| | - Shijie Xie
- Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China; School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China; Instititue of International Rivers and Eco-security, Yunnan Key Laboratory of International Rivers and Trans-Boundary Eco-security, Yunnan University, Kunming 650091, China
| | - Liping Kong
- Instititue of International Rivers and Eco-security, Yunnan Key Laboratory of International Rivers and Trans-Boundary Eco-security, Yunnan University, Kunming 650091, China
| | - Ying Pan
- Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China; School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China.
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8
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Wu J, Zhao N, Zhang P, Zhu L, Lu Y, Lei X, Bai Z. Nitrate enhances cadmium accumulation through modulating sulfur metabolism in sweet sorghum. CHEMOSPHERE 2023; 313:137413. [PMID: 36455657 DOI: 10.1016/j.chemosphere.2022.137413] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 11/11/2022] [Accepted: 11/26/2022] [Indexed: 06/17/2023]
Abstract
Sweet sorghum deploys tremendous potential for phytoremediation of cadmium (Cd)-polluted soils. Nitrate increases Cd accumulation in sweet sorghum, but the mechanism underlying this is still elusive. Sulfur-containing metabolites have been corroborated to play important roles in Cd tolerance in plants. Thus, whether sulfur metabolism contributed to nitrate-increased Cd accumulation in sweet sorghum was investigated in the present study. Two-way ANOVA analysis showed that most sulfur-containing metabolites concentrations and relevant enzymes activities were regulated by nitrate, Cd and interplay of nitrate and Cd. By using grey correlation analysis and Pearson correlation coefficient, Cd accumulation in shoots as affected by nitrate was also mainly ascribed to sulfur metabolism. ATP sulfurylase (ATPS) activities and non-protein thiol (NPT) concentrations in leaves were the two prominent factors that positively correlated with Cd accumulation in shoots. Excess nitrate elevated ATPS activities in leaves which contributed to increased NPT and phytochelatins (PCs) concentrations in leaves. Nitrate enhanced Cd accumulation in shoots of sweet sorghum under a low level of Cd treatment. Intriguingly, Cd accumulation in shoots of sweet sorghum was similar between a low level and a high level of Cd treatment. Principal Components Analysis (PCA) based on 34 parameters failed to separate the low Cd treatment from the high Cd treatment either, suggesting sweet sorghum is exclusively suitable for phytoremediation of slight Cd-polluted arable lands. Taken together, enhanced Cd accumulation in shoots of sweet sorghum by excess nitrate application is closely correlated with sulfur metabolism containing elevated ATPS activities, NPT and PCs concentrations in leaves.
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Affiliation(s)
- Jiawen Wu
- College of Life Sciences, Yan'an University, Yan'an, Shaanxi, 716000, China.
| | - Na Zhao
- College of Life Sciences, Yan'an University, Yan'an, Shaanxi, 716000, China
| | - Pan Zhang
- College of Life Sciences, Yan'an University, Yan'an, Shaanxi, 716000, China
| | - Lin Zhu
- College of Life Sciences, Yan'an University, Yan'an, Shaanxi, 716000, China
| | - Yuan Lu
- College of Life Sciences, Yan'an University, Yan'an, Shaanxi, 716000, China
| | - Xin Lei
- College of Life Sciences, Yan'an University, Yan'an, Shaanxi, 716000, China
| | - Zhenqing Bai
- College of Life Sciences, Yan'an University, Yan'an, Shaanxi, 716000, China.
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9
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Zhang LD, Song LY, Dai MJ, Guo ZJ, Wei MY, Li J, Xu CQ, Zhu XY, Zheng HL. Cadmium promotes the absorption of ammonium in hyperaccumulator Solanum nigrum L. mediated by ammonium transporters and aquaporins. CHEMOSPHERE 2022; 307:136031. [PMID: 35981624 DOI: 10.1016/j.chemosphere.2022.136031] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 08/06/2022] [Accepted: 08/08/2022] [Indexed: 06/15/2023]
Abstract
Cadmium (Cd) is a toxic heavy metal affecting the normal growth of plants. Nitrate (NO3-) and ammonium (NH4+) are the primary forms of inorganic nitrogen (N) absorbed by plants. However, the mechanism of N absorption and regulation under Cd stress remains unclear. This study found that: (1) Cd treatment affected the biomass, root length, and Cd2+ flux in Solanum nigrum seedling roots. Specifically, 50 μM Cd significantly inhibited NO3- influx while increased NH4+ influx compared with 0 and 5 μM Cd treatments measured by non-invasive micro-test technology. (2) qRT-PCR analysis showed that 50 μM Cd inhibited the expressions of nitrate transporter genes, SnNRT2;4 and SnNRT2;4-like, increased the expressions of ammonium transporter genes, SnAMT1;2 and SnAMT1;3, in the roots. (3) Under NH4+ supply, 50 μM Cd significantly induced the expressions of the aquaporin genes, SnPIP1;5, SnPIP2;7, and SnTIP2;1. Our results showed that 50 μM Cd stress promoted NH4+ absorption by up-regulating the gene expressions of NH4+ transporter and aquaporins, suggesting that high Cd stress can affect the preference of N nutrition in S. nigrum.
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Affiliation(s)
- Lu-Dan Zhang
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, 361005, PR China
| | - Ling-Yu Song
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, 361005, PR China
| | - Ming-Jin Dai
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, 361005, PR China
| | - Ze-Jun Guo
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, 361005, PR China
| | - Ming-Yue Wei
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, 361005, PR China
| | - Jing Li
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, 361005, PR China
| | - Chao-Qun Xu
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, 361005, PR China
| | - Xue-Yi Zhu
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, 361005, PR China
| | - Hai-Lei Zheng
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, 361005, PR China.
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Zhang L, He Y, Lin D, Yao Y, Song N, Wang F. Co-application of biochar and nitrogen fertilizer promotes rice performance, decreases cadmium availability, and shapes rhizosphere bacterial community in paddy soil. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 308:119624. [PMID: 35718049 DOI: 10.1016/j.envpol.2022.119624] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 06/04/2022] [Accepted: 06/12/2022] [Indexed: 06/15/2023]
Abstract
Cadmium (Cd) contamination in soil has posed a great threat to crop safety and yield as well as soil quality. Biochar blended with nitrogen fertilizer have been reported to be effective in remediating Cd-contaminated soil. However, the influence of co-application of biochar and nitrogen fertilizer on the Cd bioavailability, rice yield and soil microbiome remains unclear. In this study, eight different treatments including control (CK), 5% biochar (B), 2.6, 3.5, 4.4 g/pot nitrogen fertilizers (N1, N2 and N3), and co-application of biochar and nitrogen fertilizers (BN1, BN2, BN3) were performed in a pot experiment with paddy soil for observations in an entire rice cycle growth period. Results showed single N increased soil available Cd content and Cd uptake in edible part of rice, while the soil available Cd content significantly decreased by 14.8% and 7.4%-11.1% under the B, BN treatments, and the Cd content in edible part of rice was significantly reduced by 35.1% and 18.5%-26.5%, respectively. Besides, B, N and BN treatments significantly increased the yield of rice by 14.3%-86.6% compared with CK, and the highest yield was gained under BN3 treatment. Soil bacterial diversity indices (Shannon, Chao1, observed species and PD whole tree index) under N2, N3 were generally improved. Cluster analysis indicated that bacterial community structures under BN treatments differed from those of CK and single N treatments. BN treatments enhanced the abundances of key bacterial phylum such as Acidobacteria, positively associated with yield, and increased the abundance of Spirochaetes, negatively correlated to soil available Cd and Cd uptake of rice. Furthermore, the regression path analysis (RPA) revealed that pH, organic matter (OM), alkaline hydrolysis of nitrogen (AHN) and available Cd were the major properties influencing Cd content in edible part of rice. Redundancy analysis (RDA) revealed that pH and available Cd played key role in shaping soil bacterial community. Thus, BN is a feasible practice for the improvements of rice growth and remediation of Cd-polluted soil.
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Affiliation(s)
- Li Zhang
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Fukang Road 31, Nankai District, Tianjin, 300191, China
| | - Yulei He
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Fukang Road 31, Nankai District, Tianjin, 300191, China
| | - Dasong Lin
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Fukang Road 31, Nankai District, Tianjin, 300191, China.
| | - Yanpo Yao
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Fukang Road 31, Nankai District, Tianjin, 300191, China
| | - Ningning Song
- Qingdao Engineering Research Center for Rural Environment, School of Resources and Environment, Qingdao Agricultural University, Qingdao, 266109, PR China
| | - Fangli Wang
- Qingdao Engineering Research Center for Rural Environment, School of Resources and Environment, Qingdao Agricultural University, Qingdao, 266109, PR China
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11
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Synergetic modulation of plant cadmium tolerance via MYB75-mediated ROS homeostasis and transcriptional regulation. PLANT CELL REPORTS 2022; 41:1515-1530. [PMID: 35503475 DOI: 10.1007/s00299-022-02871-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 03/25/2022] [Indexed: 02/08/2023]
Abstract
KEY MESSAGE MYB75 enhances plant cadmium tolerance by mediating ROS homeostasis and cadmium tolerance-related genes expression. Cadmium (Cd) is a heavy metal with biological toxicity, which can be detoxified through chelation and compartmentation in plants. Transcriptional regulation mediates plant Cd tolerance by modulating these processes. However, the mechanism remains to be studied. Our results showed a previously unknown function of MYB75 transcription factor in the regulation of Cd tolerance. Cd exposure stimulates anthocyanin accumulation by raising MYB75 expression. Enhanced Cd tolerance was observed in the MYB75-overexpressing plants, whereas increased Cd sensitivity was found in the MYB75 loss-of-function mutants. Under Cd stress conditions, lower reactive oxygen species (ROS) levels were detected in MYB75-overexpressing plants than in wild type plants. In contrast, higher ROS levels were found in MYB75 loss-of-function mutants. Overexpression of MYB75 was associated with increased glutathione (GSH) and phytochelatin (PC) content under Cd exposure. Furthermore, the expression of Cd stress-related gene including ACBP2 and ABCC2 was elevated in MYB75-overexpressing plants, and this upregulation was mediated through the mechanism by which MYB75 directly bind to the promoter of ACBP2 and ABCC2. Our findings reveal an important role for MYB75 in the regulation of plant Cd tolerance via anthocyanin-mediated ROS homeostasis, and through upregulation of Cd stress-related gene at the transcriptional level.
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12
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Zhang LD, Liu X, Wei MY, Guo ZJ, Zhao ZZ, Gao CH, Li J, Xu JX, Shen ZJ, Zheng HL. Ammonium has stronger Cd detoxification ability than nitrate by reducing Cd influx and increasing Cd fixation in Solanum nigrum L. JOURNAL OF HAZARDOUS MATERIALS 2022; 425:127947. [PMID: 34896722 DOI: 10.1016/j.jhazmat.2021.127947] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 11/11/2021] [Accepted: 11/26/2021] [Indexed: 06/14/2023]
Abstract
Cadmium (Cd) is a harmful heavy metal that affects the growth and development of plants. Nitrogen (N) is an essential nutrient for plants, and appropriate N management can improve Cd tolerance. The aim of our study was to explore the effects of different forms of N on the molecular and physiological responses of the hyperaccumulator Solanum nigrum to Cd toxicity. Measurement of biomass, photosynthetic parameters, and Cd2+ fluxes using non-invasive micro-test technique, Cd fluorescent dying, biochemical methods and quantitative real-time PCR analysis were performed in our study. Our results showed that ammonium (NH4+) has stronger Cd detoxification ability than nitrate (NO3-), which are likely attributed to the following three reasons: (1) NH4+ decreased the influx and accumulation of Cd2+ by regulating the transcription of Cd transport-related genes; (2) the ameliorative effects of NH4+ were accompanied by the increased retention of Cd in the cell walls of roots; and (3) NH4+ up-regulated SnExp expression.
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Affiliation(s)
- Lu-Dan Zhang
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361005, PR China
| | - Xiang Liu
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361005, PR China; Taiyuan University of Technology, Taiyuan, Shanxi 030024, PR China
| | - Ming-Yue Wei
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361005, PR China
| | - Ze-Jun Guo
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361005, PR China
| | - Zhi-Zhu Zhao
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361005, PR China
| | - Chang-Hao Gao
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361005, PR China
| | - Jing Li
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361005, PR China
| | - Jian-Xin Xu
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361005, PR China
| | - Zhi-Jun Shen
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361005, PR China
| | - Hai-Lei Zheng
- Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361005, PR China.
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13
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Wu J, Li R, Lu Y, Bai Z. Sustainable management of cadmium-contaminated soils as affected by exogenous application of nutrients: A review. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 295:113081. [PMID: 34171783 DOI: 10.1016/j.jenvman.2021.113081] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/07/2021] [Accepted: 06/11/2021] [Indexed: 06/13/2023]
Abstract
Cadmium (Cd) pollution in arable land is of great concern as it impairs plant growth and further threats human health via food-chain. Exogenous supplementation of nutrients is an environmentally-friendly, cost-effective, convenient and feasible strategy for regulating Cd uptake, transport and accumulation in plants. To sustain Cd-contaminated soils management, on the one hand, a low level of the Cd-contaminated soil is expected to cultivate crops with decreased Cd accumulation as affected by exogenous nutrients application, on another hand, a high level of the Cd-contaminated soil is suggested to cultivate phytoextraction plants with increased Cd accumulation as affected by exogenous nutrients application. Nevertheless, effects of nutrients on Cd accumulation in plants are still ambiguous. Thus, data of Cd accumulation in shoots of plants as affected by exogenous application of nutrients were collected from previously published articles between 2005 and 2021 in the present study. According to the data, exogenous supply of calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn) and silicon (Si) to a larger extent decrease Cd amounts in shoots of plants. By contrast, exogenous nitrogen (N), and deficient Ca, Mg and Fe supply have a great possibility to increase Cd amounts in shoots of plants. Although exogenous application of phosphorus (P), sulfur (S), potassium (K), zinc (Zn) and selenium (Se) have a great opportunity to increase biomass, they show different effects on Cd concentrations. As a result, the odds are even for increasing and decreasing Cd amounts in shoots of plants. Taken together, exogenous application of Ca, Mg, Fe, Mn and Si might decrease Cd accumulation in plants that are recommended for crops production. Exogenous N and deficient Ca, Mg and Fe supply might increase Cd accumulation in plants that are recommended for phytoextraction plants. Exogenous application of P, S, K, Zn and Se have half a chance to increase or decrease Cd accumulation in plants. Therefore, dosages, forms and species should be taken into account when exogenous P, S, K, Zn and Se are added.
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Affiliation(s)
- Jiawen Wu
- College of Life Sciences, Yan'an University, Yan'an, Shaanxi, 716000, China.
| | - Ruijuan Li
- College of Life Sciences, Yan'an University, Yan'an, Shaanxi, 716000, China
| | - Yuan Lu
- College of Life Sciences, Yan'an University, Yan'an, Shaanxi, 716000, China
| | - Zhenqing Bai
- College of Life Sciences, Yan'an University, Yan'an, Shaanxi, 716000, China
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Guan M, Chen M, Cao Z. NRT2.1, a major contributor to cadmium uptake controlled by high-affinity nitrate transporters. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 218:112269. [PMID: 33932653 DOI: 10.1016/j.ecoenv.2021.112269] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 06/12/2023]
Abstract
Management of nitrogen fertilizer is a good strategy for controlling cadmium (Cd) accumulation in plants. Some progress has already been made but much remains to be done. Here, we show that mutants with loss of function of nitrate transporter1.1 (NRT1.1) or nitrate transporter2.1 (NRT2.1) had lower Cd concentrations than wild-type plants under low-nitrate conditions. However, this was eliminated when plants were cultivated in nitrate-free medium or supplied with Cd and nitrate alternately. These findings indicate that inhibition of NRT1.1 or NRT2.1 activity reduces Cd accumulation in plants, and depends on the presence of nitrate. The results showing that nrt2.1-2 mutants had the lowest Cd concentrations compared with Col-0, nrt1.1 and nrt2.4 plants, proves that NRT2.1 is the major contributor to Cd uptake controlled by nitrate high-affinity transporters. NRT2.1 acts as the major contributor to nitrate uptake under Cd stress in low-nitrate conditions, and contributes about 50% to nitrate uptake, while NRT1.1 contributes only 10%, and little is known regarding the role of NRT2.2 and NRT2.4 on nitrate uptake in medium with 200 μM nitrate. Positive correlations between nitrate uptake and Cd concentration in plants were also observed. Collectively, NRT2.1 acts as the major contributor to Cd uptake by controlling nitrate uptake in nitrate high-affinity systems.
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Affiliation(s)
- MeiYan Guan
- Rice Product Quality Supervision and Inspection Center, China National Rice Research Institute, Hangzhou 310006, China
| | - MingXue Chen
- Rice Product Quality Supervision and Inspection Center, China National Rice Research Institute, Hangzhou 310006, China
| | - ZhenZhen Cao
- Rice Product Quality Supervision and Inspection Center, China National Rice Research Institute, Hangzhou 310006, China.
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Silicon fertigation and salicylic acid foliar spraying mitigate ammonium deficiency and toxicity in Eucalyptus spp. clonal seedlings. PLoS One 2021; 16:e0250436. [PMID: 33886651 PMCID: PMC8061938 DOI: 10.1371/journal.pone.0250436] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 04/07/2021] [Indexed: 11/19/2022] Open
Abstract
Nitrogen deficiency and toxicity, primarily in its ammonium form (NH4+), can suppress plant growth and development. The use of silicon (Si) or salicylic acid (SA) may be an alternative to minimize the harmful effects of nutrient imbalances caused by NH4+, thereby improving the photosynthetic efficiency of plants. The aim of the present study was to assess the action of fertigation-applied Si and SA foliar spraying in mitigating NH4+ toxicity and deficiency in eucalyptus clonal seedlings. Two experiments were performed with eucalyptus clonal seedlings (Eucalyptus urophylla x Eucalyptus grandis), in a greenhouse. Both were carried out using a 4x2 factorial design and four concentrations of NH4+ (5, 15, 30 and 60 mmol L-1), in the absence and presence of Si (2 mmol L-1), in experiment I; or with and without SA foliar application (10−2 mmol L-1), in experiment II, with six repetitions. Nitrogen content rose as a result of increasing N-NH4+ concentration in the nutrient solution, and Si supplied via the nutrient solution was efficient in increasing the Si content in eucalyptus seedlings. The rise in N-NH4+ concentration favored the maintenance of the photosynthetic apparatus, but high N-NH4+ concentration increased energy loss through fluorescence and decreased the efficiency of photosystem II. The addition of Si to the nutrient solution proved to be beneficial to the photosynthetic apparatus by decreasing F0 at 15 and 30 mmol L-1 of NH4+; and Fm at all NH4+ concentrations studied. In addition, the beneficial element also increases Fv/Fm at all NH4+ concentrations studied. SA foliar application was also efficient in reducing photosynthetic energy losses by decreasing F0 and Fm at all NH4+ concentrations studied. However, SA only increased the Fv/Fm at the high concentrations studied (30 and 60 mmol L-1 of NH4+). Nitrogen disorder by deficiency or N-NH4+ toxicity reduced shoot dry mass production. The addition of Si to the nutrient solution and SA foliar application increased shoot dry mass production at all N-NH4+ concentrations studied, and benefitted the photosynthetic apparatus by decreasing fluorescence and improving the quantum efficiency of photosystem II as well as dry mass production.
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Bai Z, Li D, Zhu L, Tang X, Wang Y, Mao R, Wu J. Nitrate Increases Cadmium Accumulation in Sweet Sorghum for Improving Phytoextraction Efficiency Rather Than Ammonium. FRONTIERS IN PLANT SCIENCE 2021; 12:643116. [PMID: 34093607 PMCID: PMC8172601 DOI: 10.3389/fpls.2021.643116] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 04/26/2021] [Indexed: 05/05/2023]
Abstract
Sweet sorghum has potential for phytoextraction of cadmium (Cd) owning to its large biomass and relatively high Cd tolerance. Nitrogen affects both growth and Cd concentrations in plants. However, different forms of nitrogen effects on Cd accumulation in sweet sorghum to improve efficiency of Cd phytoremediation is still elusive. In this study, nitrate substantially promoted both dry weight and Cd concentrations in leaves, stems + sheaths and roots of sweet sorghum when compared with ammonium. As a result, Cd accumulation in nitrate-supplied sweet sorghum was around 3.7-fold of that in ammonium-supplied plants under unbuffered pH condition, while the fold was about 2.2 under buffered pH condition. We speculated pH values and Cd species in the growth medium to some extent contributed to increased Cd accumulation as affected by nitrate. Net photosynthesis rate and Fv/Fm of nitrate-treated plants under Cd stress were higher than that of ammonium-treated plants when the pH was unbuffered. Responses of antioxidant capacity in roots to Cd stress with nitrate application were stronger than that with ammonium supplementation. Taken together, nitrate is more suitable than ammonium for Cd phytoextraction by using sweet sorghum, which is able to enhance at least double efficiency of phytoextraction.
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Affiliation(s)
- Zhenqing Bai
- Shaanxi Key Laboratory of Chinese Jujube, Yan’an University, Yan’an, China
- College of Life Sciences, Yan’an University, Yan’an, China
| | - Dan Li
- College of Life Sciences, Yan’an University, Yan’an, China
| | - Lin Zhu
- College of Life Sciences, Yan’an University, Yan’an, China
| | - Xiaoyu Tang
- College of Life Sciences, Yan’an University, Yan’an, China
| | - Yanfeng Wang
- Shaanxi Key Laboratory of Chinese Jujube, Yan’an University, Yan’an, China
- College of Life Sciences, Yan’an University, Yan’an, China
| | - Renjun Mao
- Shaanxi Key Laboratory of Chinese Jujube, Yan’an University, Yan’an, China
- College of Life Sciences, Yan’an University, Yan’an, China
| | - Jiawen Wu
- Shaanxi Key Laboratory of Chinese Jujube, Yan’an University, Yan’an, China
- College of Life Sciences, Yan’an University, Yan’an, China
- *Correspondence: Jiawen Wu, ; orcid.org/0000-0001-8646-126X
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