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Lao A, Wu H, Huang X, Huang K, Luo X, Zheng Z. Sustained and enhanced inhibitory effects of allelochemicals on Microcystis Aeruginosa during its recruitment stage. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 946:173904. [PMID: 38885712 DOI: 10.1016/j.scitotenv.2024.173904] [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: 03/18/2024] [Revised: 06/04/2024] [Accepted: 06/08/2024] [Indexed: 06/20/2024]
Abstract
Microcystis aeruginosa is the main toxic strain in cyanobacterial blooms, and the recruitment stage in its temperature-dependent seasonal succession is considered as the key to its subsequent growth. In this study, a protocol with specific temperature settings was developed as the simulated recruitment stage in order to investigate and confirm the superior inhibitory effects of allelochemicals on M. aeruginosa at that stage of recruitment. One of the most common allelochemicals, gallic acid (GA) (10 mg/L, 20 mg/L) was employed to treat M. aeruginosa under initially low temperature condition (15 °C), then intermediate (20 °C) and last normal (26 °C), which corresponds to the critical temperatures for cyanobacterial recruitment and growth. Growth, metabolism, photosynthetic activity, extracellular polysaccharides (EPS) and microcystins (MCs) release were analyzed and discussed in this study, and a more sustained and better inhibitory effect over a 20-day period was achieved. Notably, GA (10 mg/L) markedly delayed the recruitment of M. aeruginosa from low temperature, with an inhibition efficiency of 85.71 %, and suppressing Fv/Fm and photosynthetic pigments production. It is also observed that M. aeruginosa at recruitment stage exhibited higher sensitivity and poorer resistance to allelochemical treatment, with variable responses suggesting that optimal dosages may alter. The antioxidant enzyme activities remained high under prolonged stress, and the secretion of EPS was stimulated, indicating that cyanobacteria were more inclined to form colonies. While the laboratory-based inhibitory mechanism appeared to increase the release of microcystins in individual cells, the actual concentration of microcystins in natural aquatic environments requires further investigation.
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Affiliation(s)
- An Lao
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
| | - Hanqi Wu
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
| | - Xuhui Huang
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
| | - Kaili Huang
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
| | - Xingzhang Luo
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
| | - Zheng Zheng
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
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Li Q, Zhou Y, Sun W, Qiao B, Cheng J, Shi S, Zhao C, Li C. Dynamic response of allelopathic potency of Taxus cuspidata Sieb. et Zucc. mediated by allelochemicals in Ficus carica Linn. root exudates. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 940:173663. [PMID: 38823714 DOI: 10.1016/j.scitotenv.2024.173663] [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: 01/29/2024] [Revised: 05/28/2024] [Accepted: 05/29/2024] [Indexed: 06/03/2024]
Abstract
In a mixed forest, certain plants can release allelochemicals that exert allelopathic effects on neighboring plants, thereby facilitating interspecific coexistence of two species. Previous studies have demonstrated that allelochemicals released from Ficus carica Linn. roots in mixed forest of F. carica and Taxus cuspidata Sieb. et Zucc. has phase characteristics over time, which can improve the soil physicochemical properties, enzyme activity and microbial diversity, thus promoting the growth of T. cuspidata. Based on the irrigation of exogenous allelochemicals, changes in soil fertility (soil physical and chemical properties, soil enzyme activity and soil microelement content) were observed in response to variations in allelochemicals during five phases of irrigation: initial disturbance phase (0-2 d), physiological compensation phase (2-8 d), screening phase (8-16 d), restore phase (16-32 d) and maturity phase (32-64 d), which was consistent with the response of soil microorganisms. The allelopathic response of growth physiological indexes of T. cuspidata, however, exhibited a slight lag behind the soil fertility, with distinct phase characteristics becoming evident on the 4th day following irrigation of allelochemicals. The findings demonstrated that the allelochemicals released by the root of F. carica induced a synergistic effect on soil fertility and microorganisms, thereby facilitating the growth of T. cuspidata. This study provides a comprehensive elucidation of the phased dynamic response-based allelopathic mechanism employed by F. carica to enhance the growth of T. cuspidata, thus establishing a theoretical basis for optimizing forest cultivation through allelopathic pathways.
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Affiliation(s)
- Qianqian Li
- Key Laboratory of Forest Plant Ecology, Ministry of Education, College of Chemistry, Chemical Engineering and Resource Utilization, Engineering Research Center of Forest Bio-preparation, Ministry of Education, Heilongjiang Provincial Key Laboratory of Ecological Utilization of Forestry-based Active Substances, Northeast Forestry University, Harbin 150040, China
| | - Yifan Zhou
- Key Laboratory of Forest Plant Ecology, Ministry of Education, College of Chemistry, Chemical Engineering and Resource Utilization, Engineering Research Center of Forest Bio-preparation, Ministry of Education, Heilongjiang Provincial Key Laboratory of Ecological Utilization of Forestry-based Active Substances, Northeast Forestry University, Harbin 150040, China
| | - Wenxue Sun
- Key Laboratory of Forest Plant Ecology, Ministry of Education, College of Chemistry, Chemical Engineering and Resource Utilization, Engineering Research Center of Forest Bio-preparation, Ministry of Education, Heilongjiang Provincial Key Laboratory of Ecological Utilization of Forestry-based Active Substances, Northeast Forestry University, Harbin 150040, China
| | - Bin Qiao
- Key Laboratory of Forest Plant Ecology, Ministry of Education, College of Chemistry, Chemical Engineering and Resource Utilization, Engineering Research Center of Forest Bio-preparation, Ministry of Education, Heilongjiang Provincial Key Laboratory of Ecological Utilization of Forestry-based Active Substances, Northeast Forestry University, Harbin 150040, China
| | - Jiabo Cheng
- Key Laboratory of Forest Plant Ecology, Ministry of Education, College of Chemistry, Chemical Engineering and Resource Utilization, Engineering Research Center of Forest Bio-preparation, Ministry of Education, Heilongjiang Provincial Key Laboratory of Ecological Utilization of Forestry-based Active Substances, Northeast Forestry University, Harbin 150040, China
| | - Sen Shi
- Key Laboratory of Forest Plant Ecology, Ministry of Education, College of Chemistry, Chemical Engineering and Resource Utilization, Engineering Research Center of Forest Bio-preparation, Ministry of Education, Heilongjiang Provincial Key Laboratory of Ecological Utilization of Forestry-based Active Substances, Northeast Forestry University, Harbin 150040, China
| | - Chunjian Zhao
- Key Laboratory of Forest Plant Ecology, Ministry of Education, College of Chemistry, Chemical Engineering and Resource Utilization, Engineering Research Center of Forest Bio-preparation, Ministry of Education, Heilongjiang Provincial Key Laboratory of Ecological Utilization of Forestry-based Active Substances, Northeast Forestry University, Harbin 150040, China.
| | - Chunying Li
- Key Laboratory of Forest Plant Ecology, Ministry of Education, College of Chemistry, Chemical Engineering and Resource Utilization, Engineering Research Center of Forest Bio-preparation, Ministry of Education, Heilongjiang Provincial Key Laboratory of Ecological Utilization of Forestry-based Active Substances, Northeast Forestry University, Harbin 150040, China.
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Jiang X, Wang M, He D, Zhu J, Yang S, Fang F, Yang L. Submerged macrophyte promoted nitrogen removal function of biofilms in constructed wetland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 914:169666. [PMID: 38184255 DOI: 10.1016/j.scitotenv.2023.169666] [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: 09/28/2023] [Revised: 11/29/2023] [Accepted: 12/23/2023] [Indexed: 01/08/2024]
Abstract
Biofilm is one of the important factors affecting nitrogen removal in constructed wetlands (CWs). However, the impact of submerged macrophyte on nitrogen conversion of biofilms on leaf of submerged macrophyte and matrix remains poorly understood. In this study, the CWs with Vallisneria natans and with artificial plant were established to investigate the effects of submerged macrophyte on nitrogen conversion and the composition of nitrogen-converting bacteria in leaf and matrix biofilms under high ammonium nitrogen (NH4+-N) loading. The 16S rRNA sequencing method was employed to explore the changes in bacterial communities in biofilms in CWs. The results showed that average removal rates of total nitrogen and NH4+-N in CW with V. natans reached 71.38% and 82.08%, respectively, representing increases of 24.19% and 28.79% compared with the control with artificial plant. Scanning electron microscope images indicated that high NH4+-N damaged the leaf cells of V. natans, leading to the cellular content release and subsequent increases of aqueous total organic carbon. However, the specific surface area and carrier function of V. natans were unaffected within 25 days. As a natural source of organic matters, submerged macrophyte provided organic matters for bacterial growth in biofilms. Bacterial composition analysis revealed the predominance of phylum Proteobacteria in CW with V. natans. The numbers of nitrifiers and denitrifiers in leaf biofilms reached 1.66 × 105 cells/g and 1.05 × 107 cells/g, as well as 2.79 × 105 cells/g and 7.41 × 107 cells/g in matrix biofilms, respectively. Submerged macrophyte significantly increased the population of nitrogen-converting bacteria and enhanced the expressions of nitrification genes (amoA and hao) and denitrification genes (napA, nirS and nosZ) in both leaf and matrix biofilms. Therefore, our study emphasized the influence of submerged macrophyte on biofilm functions and provided a scientific basis for nitrogen removal of biofilms in CWs.
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Affiliation(s)
- Xue Jiang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, PR China
| | - Mengmeng Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, PR China
| | - Di He
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, PR China
| | - Jinling Zhu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, PR China
| | - Shunqing Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, PR China
| | - Fei Fang
- School of Resources and Environment, Anqing Normal University, Anqing 246133, PR China
| | - Liuyan Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, PR China.
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