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Yu YZ, Liu HT, Yang F, Li L, Schäufele R, Tcherkez G, Schnyder H, Gong XY. δ13C of bulk organic matter and cellulose reveal post-photosynthetic fractionation during ontogeny in C4 grass leaves. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:1451-1464. [PMID: 37943576 DOI: 10.1093/jxb/erad445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 11/04/2023] [Indexed: 11/10/2023]
Abstract
The 13C isotope composition (δ13C) of leaf dry matter is a useful tool for physiological and ecological studies. However, how post-photosynthetic fractionation associated with respiration and carbon export influences δ13C remains uncertain. We investigated the effects of post-photosynthetic fractionation on δ13C of mature leaves of Cleistogenes squarrosa, a perennial C4 grass, in controlled experiments with different levels of vapour pressure deficit and nitrogen supply. With increasing leaf age class, the 12C/13C fractionation of leaf organic matter relative to the δ13C of atmosphere CO2 (ΔDM) increased while that of cellulose (Δcel) was almost constant. The divergence between ΔDM and Δcel increased with leaf age class, with a maximum value of 1.6‰, indicating the accumulation of post-photosynthetic fractionation. Applying a new mass balance model that accounts for respiration and export of photosynthates, we found an apparent 12C/13C fractionation associated with carbon export of -0.5‰ to -1.0‰. Different ΔDM among leaves, pseudostems, daughter tillers, and roots indicate that post-photosynthetic fractionation happens at the whole-plant level. Compared with ΔDM of old leaves, ΔDM of young leaves and Δcel are more reliable proxies for predicting physiological parameters due to the lower sensitivity to post-photosynthetic fractionation and the similar sensitivity in responses to environmental changes.
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Affiliation(s)
- Yong Zhi Yu
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Hai Tao Liu
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
- College of Resources and Environment, Henan Agricultural University, Zhengzhou 450046, China
| | - Fang Yang
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
- College of Resources and Environment, Jilin Agricultural University, Changchun 130117, China
| | - Lei Li
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Guillaume Tcherkez
- Research School of Biology, ANU Joint College of Science, Australian National University, Canberra ACT 0200, Australia
- Institut de Recherche en Horticulture et Semences, INRAe, Université d'Angers, 42 rue Georges Morel, 49070 Beaucouzé, France
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Xiao Ying Gong
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fuzhou, China
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2
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Li J, Meng B, Yang X, Cui N, Zhao T, Chai H, Zhang T, Sun W. Suppression of AMF accelerates N2O emission by altering soil bacterial community and genes abundance under varied precipitation conditions in a semiarid grassland. Front Microbiol 2022; 13:961969. [PMID: 36003936 PMCID: PMC9393504 DOI: 10.3389/fmicb.2022.961969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 07/06/2022] [Indexed: 11/13/2022] Open
Abstract
Nitrous oxide (N2O) is one of the most important greenhouse gases contributing to global climate warming. Recently, studies have shown that arbuscular mycorrhizal fungi (AMF) could reduce N2O emissions in terrestrial ecosystems; however, the microbial mechanisms of how AMF reduces N2O emissions under climate change are still not well understood. We tested the influence of AMF on N2O emissions by setting up a gradient of precipitation intensity (+50%, +30%, ambient (0%), −30%, −50%, and −70%) and manipulating the presence or exclusion of AMF hyphae in a semiarid grassland located in northeast China. Our results showed that N2O fluxes dramatically declined with the decrease in precipitation gradient during the peak growing season (June–August) in both 2019 and 2020. There was a significantly positive correlation between soil water content and N2O fluxes. Interestingly, N2O fluxes significantly decreased when AMF were present compared to when they were absent under all precipitation conditions. The contribution of AMF to mitigate N2O emission increased gradually with decreasing precipitation magnitudes, but no contribution in the severe drought (−70%). AMF significantly reduced the soil’s available nitrogen concentration and altered the composition of the soil bacteria community including those associated with N2O production. Hyphal length density was negatively correlated with the copy numbers of key genes for N2O production (nirK and nirS) and positively correlated with the copy numbers of key genes for N2O consumption (nosZ). Our results highlight that AMF would reduce the soil N2O emission under precipitation variability in a temperate grassland except for extreme drought.
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Affiliation(s)
- Junqin Li
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Bo Meng
- Institute of Ecology, College of Urban and Environmental Science, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China
| | - Xuechen Yang
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin, China
| | - Nan Cui
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Tianhang Zhao
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Hua Chai
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Tao Zhang
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
- *Correspondence: Tao Zhang,
| | - Wei Sun
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
- Wei Sun,
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Bolortuya B, Kawabata S, Yamagami A, Davaapurev BO, Takahashi F, Inoue K, Kanatani A, Mochida K, Kumazawa M, Ifuku K, Jigjidsuren S, Battogtokh T, Udval G, Shinozaki K, Asami T, Batkhuu J, Nakano T. Transcriptome Analysis of Chloris virgata, Which Shows the Fastest Germination and Growth in the Major Mongolian Grassland Plant. FRONTIERS IN PLANT SCIENCE 2021; 12:684987. [PMID: 34262584 PMCID: PMC8275185 DOI: 10.3389/fpls.2021.684987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 04/26/2021] [Indexed: 06/13/2023]
Abstract
Plants in Mongolian grasslands are exposed to short, dry summers and long, cold winters. These plants should be prepared for fast germination and growth activity in response to the limited summer rainfall. The wild plant species adapted to the Mongolian grassland environment may allow us to explore useful genes, as a source of unique genetic codes for crop improvement. Here, we identified the Chloris virgata Dornogovi accession as the fastest germinating plant in major Mongolian grassland plants. It germinated just 5 h after treatment for germination initiation and showed rapid growth, especially in its early and young development stages. This indicates its high growth potential compared to grass crops such as rice and wheat. By assessing growth recovery after animal bite treatment (mimicked by cutting the leaves with scissors), we found that C. virgata could rapidly regenerate leaves after being damaged, suggesting high regeneration potential against grazing. To analyze the regulatory mechanism involved in the high growth potential of C. virgata, we performed RNA-seq-based transcriptome analysis and illustrated a comprehensive gene expression map of the species. Through de novo transcriptome assembly with the RNA-seq reads from whole organ samples of C. virgata at the germination stage (2 days after germination, DAG), early young development stage (8 DAG), young development stage (17 DAG), and adult development stage (28 DAG), we identified 21,589 unified transcripts (contigs) and found that 19,346 and 18,156 protein-coding transcripts were homologous to those in rice and Arabidopsis, respectively. The best-aligned sequences were annotated with gene ontology groups. When comparing the transcriptomes across developmental stages, we found an over-representation of genes involved in growth regulation in the early development stage in C. virgata. Plant development is tightly regulated by phytohormones such as brassinosteroids, gibberellic acid, abscisic acid, and strigolactones. Moreover, our transcriptome map demonstrated the expression profiles of orthologs involved in the biosynthesis of these phytohormones and their signaling networks. We discuss the possibility that C. virgata phytohormone signaling and biosynthesis genes regulate early germination and growth advantages. Comprehensive transcriptome information will provide a useful resource for gene discovery and facilitate a deeper understanding of the diversity of the regulatory systems that have evolved in C. virgata while adapting to severe environmental conditions.
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Affiliation(s)
- Byambajav Bolortuya
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
- School of Engineering and Applied Sciences, National University of Mongolia, Ulaanbaatar, Mongolia
- Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science, Tsukuba, Japan
| | | | - Ayumi Yamagami
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Bekh-Ochir Davaapurev
- School of Engineering and Applied Sciences, National University of Mongolia, Ulaanbaatar, Mongolia
| | - Fuminori Takahashi
- Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science, Tsukuba, Japan
| | - Komaki Inoue
- Bioproductivity Informatics Research Team, RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Asaka Kanatani
- Bioproductivity Informatics Research Team, RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Keiichi Mochida
- Bioproductivity Informatics Research Team, RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Minoru Kumazawa
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Kentaro Ifuku
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Sodnomdarjaa Jigjidsuren
- Research Institute of Animal Husbandry, Mongolian University of Life Science, Ulaanbaatar, Mongolia
| | - Tugsjargal Battogtokh
- Research Institute of Animal Husbandry, Mongolian University of Life Science, Ulaanbaatar, Mongolia
| | - Gombosuren Udval
- Research Institute of Animal Husbandry, Mongolian University of Life Science, Ulaanbaatar, Mongolia
| | - Kazuo Shinozaki
- Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science, Tsukuba, Japan
| | - Tadao Asami
- Department of Applied Biological Chemistry, The University of Tokyo, Tokyo, Japan
| | - Javzan Batkhuu
- School of Engineering and Applied Sciences, National University of Mongolia, Ulaanbaatar, Mongolia
| | - Takeshi Nakano
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
- School of Engineering and Applied Sciences, National University of Mongolia, Ulaanbaatar, Mongolia
- Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science, Tsukuba, Japan
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4
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Yang X, Henry HAL, Zhong S, Meng B, Wang C, Gao Y, Sun W. Towards a mechanistic understanding of soil nitrogen availability responses to summer vs. winter drought in a semiarid grassland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 741:140272. [PMID: 32570067 DOI: 10.1016/j.scitotenv.2020.140272] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/14/2020] [Accepted: 06/14/2020] [Indexed: 06/11/2023]
Abstract
More frequent and intense drought events resulting from climate change are anticipated to become important drivers of change for terrestrial ecosystem function by affecting water and nutrient cycles. In semiarid grasslands, the responses of soil nitrogen availability to severe drought and the underlying mechanisms are largely unknown. Moreover, the responses and mechanisms may vary between summer and winter drought. We examined soil nitrogen availability responses to extreme reductions in precipitation over summer and winter using a field experiment in a semiarid grassland located in northeast China, and we explored the mechanisms by examining associated changes in abiotic factors (soil property responses) and biotic factors (plant and soil microbial responses). The results demonstrated that both the summer and winter severe drought treatments significantly reduced plant and microbial biomass, whereas summer drought also changed soil microbial community structure. Summer drought, winter drought and combined summer and winter drought decreased the resistance of soil nitrogen availability by 38.7 ± 11.1%, 43.3 ± 11.4% and 43.8 ± 6.0%, respectively. While both changes in abiotic factors (reduced soil water content and total nitrogen content) and biotic factors (reduced plant and microbial biomass) explained the resistance of soil nitrogen availability to drought over summer, only changes in biotic factors (reduced plant and microbial biomass) explained the legacy effect of winter drought. Our results highlight that severe drought can have important consequences for nitrogen cycling in semiarid grasslands, and that both the effects of summer and winter drought must be accounted for in predicting these responses.
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Affiliation(s)
- Xuechen Yang
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, Jilin 130024, PR China
| | - Hugh A L Henry
- Department of Biology, University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Shangzhi Zhong
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, Jilin 130024, PR China
| | - Bo Meng
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, Jilin 130024, PR China
| | - Chengliang Wang
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, Jilin 130024, PR China
| | - Ying Gao
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, Jilin 130024, PR China
| | - Wei Sun
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, Jilin 130024, PR China.
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Wang K, Zhong S, Sun W. Clipping defoliation and nitrogen addition shift competition between a C 3 grass (Leymus chinensis) and a C 4 grass (Hemarthria altissima). PLANT BIOLOGY (STUTTGART, GERMANY) 2020; 22:221-232. [PMID: 31671249 DOI: 10.1111/plb.13064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 10/22/2019] [Indexed: 06/10/2023]
Abstract
Human-induced disturbances, including grazing and clipping, that cause defoliation are common in natural grasslands. Plant functional type differences in the ability to compensate for this tissue loss may influence interspecific competition. To explore the effects of different intensities of clipping and nitrogen (N) addition on compensatory growth and interspecific competition, we measured accumulated aboveground biomass (AGB), belowground biomass (BGB), tiller number, non-structural carbohydrates concentrations and leaf gas exchange parameters in two locally co-occurring species (the C3 grass Leymus chinensis and the C4 grass Hemarthria altissima) growing in monoculture and in mixture. For both grasses, the clipping treatment had significant impacts on the accumulated AGB, and the 40% clipping treatment had the largest effect. BGB gradually decreased with increasing defoliation intensity. Severe defoliation caused a significant increase in tiller number. Stored carbohydrates in the belowground biomass were mobilised and transported aboveground for the growth of new leaves to compensate for clipping-induced injury. The net CO2 assimilation rate (A) of the remaining leaves increased with clipping intensity and peaked under clipping intensities of 20% or 40%. Nitrogen addition, at a rate of 10 g·N·m-2 ·year-1 , enhanced A of the remaining leaves and non-structural carbohydrate concentrations, which benefited plant compensatory growth, especially for the C3 grass. Under the mixed planting conditions, the clipping and N addition treatments lowered the competitive advantage of the C4 grass. The results suggest that a combination of defoliation and N deposition have the potential to benefit the coexistence of C3 and C4 grasses.
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Affiliation(s)
- K Wang
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, Jilin Province, China
| | - S Zhong
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, Jilin Province, China
| | - W Sun
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, Jilin Province, China
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Drought sensitivity of aboveground productivity in Leymus chinensis meadow steppe depends on drought timing. Oecologia 2019; 191:685-696. [PMID: 31535253 DOI: 10.1007/s00442-019-04506-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 09/06/2019] [Indexed: 10/26/2022]
Abstract
There is limited understanding of the combined effects of discrete climate extremes and chronic environmental changes on ecosystem processes and functioning. We assessed the interactions of extreme drought timing (45 days, in spring or summer) and nitrogen (N) addition in a full factorial field experiment in a Leymus chinensis-dominated meadow steppe in northeast China. We evaluated the resistance and recovery of the grassland (calculated in terms of aboveground biomass) to these two drought events. The spring drought reduced aboveground biomass by 28% in the unfertilized plots and by 33% in the fertilized plots, and the effects persisted during the subsequent post-drought period within the same growing season; however, the summer drought had no significant influence on aboveground biomass. Although there were no significant interactive effects between drought timing and N addition, we observed a potential trend of N addition increasing the proportion of aboveground biomass suppressed by spring drought but not summer drought. Moreover, the drought resistance of the aboveground biomass was positively correlated with the response of the belowground biomass to drought. One year after the extreme drought events, the spring drought effects on aboveground and belowground biomass were negligible. Our results indicate that the drought sensitivity of productivity likely depends on the phenological and morphological traits of the single highly dominant species (Leymus chinensis) in this meadow steppe.
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Zhong S, Xu Y, Meng B, Loik ME, Ma JY, Sun W. Nitrogen Addition Increases the Sensitivity of Photosynthesis to Drought and Re-watering Differentially in C 3 Versus C 4 Grass Species. FRONTIERS IN PLANT SCIENCE 2019; 10:815. [PMID: 31333687 PMCID: PMC6616207 DOI: 10.3389/fpls.2019.00815] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 06/06/2019] [Indexed: 05/03/2023]
Abstract
Global change factors, such as variation in precipitation regimes and nitrogen (N) deposition, are likely to occur simultaneously and may have profound impacts on the relative abundance of grasses differing in functional traits, such as C3 and C4 species. We conducted an extreme drought and re-watering experiment to understand differences in the resistance and recovery abilities of C3 and C4 grasses under different N deposition scenarios. A C3 perennial grass (Leymus chinensis) and two C4 grasses (annual species Chloris virgata and perennial species Hemarthria altissima) that co-occur in Northeast China were selected as experimental plants. For both C3 and C4 grasses, N addition caused a strong increase in biomass and resulted in more severe drought stress, leading to a change in the dominant photosynthetic limitation during the drought periods. Although N addition increased antioxidant enzyme activities and protective solute concentrations, the carbon fixing capacity did not fully recover to pre-drought levels by the end of the re-watering period. N addition resulted in lower resilience under the drought conditions and lower resistance at the end of the re-watering. However, N addition led to faster recovery of photosynthesis, especially in the C3 grass, which indicate that the effect of N addition on photosynthesis during drought was asymmetric, especially in the plants with different photosynthetic nitrogen use efficiency (PNUE). These findings demonstrated that nitrogen deposition may significant alter the susceptibility of C3 and C4 grass species to drought stress and re-watering, highlighting the asymmetry between resistance and resilience and to improve our understanding about plant responses to climate change.
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Affiliation(s)
- Shangzhi Zhong
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Yueqiao Xu
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Bo Meng
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Michael E Loik
- Department of Environmental Studies, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Jian-Ying Ma
- Key Laboratory of Biogeography and Bioresources in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi, China
| | - Wei Sun
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
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Li J, Meng B, Chai H, Yang X, Song W, Li S, Lu A, Zhang T, Sun W. Arbuscular Mycorrhizal Fungi Alleviate Drought Stress in C 3 ( Leymus chinensis) and C 4 ( Hemarthria altissima) Grasses via Altering Antioxidant Enzyme Activities and Photosynthesis. FRONTIERS IN PLANT SCIENCE 2019; 10:499. [PMID: 31114594 PMCID: PMC6503820 DOI: 10.3389/fpls.2019.00499] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/01/2019] [Indexed: 05/10/2023]
Abstract
As one of the most important limiting factors of grassland productivity, drought is predicted to increase in intensity and frequency. Greenhouse studies suggest that arbuscular mycorrhizal fungi (AMF) can improve plant drought resistance. However, whether AMF can improve plant drought resistance in field conditions and whether the effects of AMF on drought resistance differ among plants with different photosynthetic pathways remain unclear. To evaluate the effect of indigenous AMF on plant drought resistance, an in situ rainfall exclusion experiment was conducted in a temperate meadow in northeast China. The results showed that AMF significantly reduced the negative effects of drought on plant growth. On average, AMF enhanced plant biomass, photosynthetic rate (A), stomatal conductance (g s), intrinsic water use efficiency (iWUE), and superoxide dismutase (SOD) activity of the C3 species Leymus chinensis by 58, 63, 38, 15, and 45%, respectively, and reduced levels of malondialdehyde (MDA) by 32% under light and moderate drought (rainfall exclusion of 30 and 50%, respectively). However, under extreme drought (rainfall exclusion of 70%), AMF elevated only aboveground biomass and catalase (CAT) activities. Averagely, AMF increased the aboveground biomass, A, and CAT activity of Hemarthria altissima (C4) by 37, 28, and 30%, respectively, under light and moderate droughts. The contribution of AMF to plant drought resistance was higher for the C3 species than that for the C4 species under both light and moderate drought conditions. The results highlight potential photosynthetic type differences in the magnitude of AMF-associated enhancement in plant drought resistance. Therefore, AMF may determine plant community structure under future climate change scenarios by affecting the drought resistance of different plant functional groups.
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Affiliation(s)
| | | | | | | | | | | | | | - Tao Zhang
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Wei Sun
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
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Shi B, Zhang J, Wang C, Ma J, Sun W. Responses of hydrolytic enzyme activities in saline-alkaline soil to mixed inorganic and organic nitrogen addition. Sci Rep 2018. [PMID: 29540738 PMCID: PMC5852051 DOI: 10.1038/s41598-018-22813-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The effects of manipulating nitrogen (N) deposition, with the use of a single form of N, on soil enzyme activities have been extensively studied. However, the impacts varying the N type (organic vs. inorganic) on soil hydrolytic enzyme activities have been less studied. We performed a 60 day incubation experiment using saline-alkaline soil. The objectives were to explore how the microbial biomass and enzyme activities respond to a mixed N addition at different inorganic to organic N ratios. The experimental design was full factorial, with two rates of N addition (10 g N m−2 and 20 g N m−2) and four ratios of N addition (inorganic N:organic N = 10:0, 7:3, 3:7, 1:9). The results showed that N addition stimulated enzyme activities involved in C, N and P cycling. Enzyme activities under mixed N addition increased compared to those under single inorganic N addition in most cases. The inorganic to organic N ratios interacted with the N addition rate to affect the enzyme activities. Our results suggest that various N fertilizers, which have different inorganic to organic N ratios, should be applied when evaluating the effects of atmospheric N deposition on the soil microbial enzyme activities and ecosystem structure and function.
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Affiliation(s)
- Baoku Shi
- Key Laboratory for Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, 130024, China
| | - Junmei Zhang
- Key Laboratory for Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, 130024, China
| | - Chengliang Wang
- Key Laboratory for Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, 130024, China
| | - Jianying Ma
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
| | - Wei Sun
- Key Laboratory for Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, 130024, China.
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Shi B, Wang Y, Meng B, Zhong S, Sun W. Effects of Nitrogen Addition on the Drought Susceptibility of the Leymus chinensis Meadow Ecosystem Vary with Drought Duration. FRONTIERS IN PLANT SCIENCE 2018. [PMID: 29535757 PMCID: PMC5835344 DOI: 10.3389/fpls.2018.00254] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
It is not clear yet how extreme drought and nitrogen (N) deposition influence grassland ecosystem functions when they are considered together, especially in complex field conditions. To explore the response of the Leymus chinensis meadow ecosystem to manipulated extreme drought (45 days), N addition and their interaction, we measured leaf photosynthetic characteristics, aboveground phytomass on the community level and ecosystem C exchange in different treatments at the middle and the end of the drought period. The extreme drought treatment decreased the leaf net CO2 assimilation rate and ecosystem C exchange [gross ecosystem productivity (GEP), ecosystem respiration and net ecosystem CO2 exchange]. In contrast, the N addition treatment increased aboveground phytomass, GEP and net ecosystem CO2 exchange. The effects of N addition on the drought susceptibility of the L. chinensis meadow ecosystem varied with drought severity. The N addition treatment alleviated drought-induced suppression of CO2 exchange at the leaf and ecosystem levels in the middle of the drought period, whereas it exacerbated drought-induced suppression of the CO2 exchange and aboveground phytomass on the community level at the end of the drought period. Given that dominance by L. chinensis is a characteristic of the studied ecosystem, knowledge of the traits of L. chinensis and its response to multiple global change drivers will be crucial for predicting future ecosystem functions. Furthermore, increasing N deposition may affect the response of the L. chinensis meadow ecosystem to further droughts by increasing carbon allocation to roots and therefore root-shoot ratios.
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Affiliation(s)
- Baoku Shi
- Key Laboratory for Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Yunbo Wang
- Key Laboratory for Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
- Key Laboratory of Grassland Resources, Ministry of Education, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, Hohhot, China
| | - Bo Meng
- Key Laboratory for Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Shangzhi Zhong
- Key Laboratory for Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Wei Sun
- Key Laboratory for Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
- *Correspondence: Wei Sun,
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