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Cabrera JCB, Hirl RT, Schäufele R, Zhu J, Liu HT, Gong XY, Ogée J, Schnyder H. Half of the 18O enrichment of leaf sucrose is conserved in leaf cellulose of a C 3 grass across atmospheric humidity and CO 2 levels. PLANT, CELL & ENVIRONMENT 2024; 47:2274-2287. [PMID: 38488789 DOI: 10.1111/pce.14881] [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: 11/06/2023] [Revised: 02/02/2024] [Accepted: 03/01/2024] [Indexed: 04/30/2024]
Abstract
The 18O enrichment (Δ18O) of cellulose (Δ18OCel) is recognized as a unique archive of past climate and plant function. However, there is still uncertainty regarding the proportion of oxygen in cellulose (pex) that exchanges post-photosynthetically with medium water of cellulose synthesis. Particularly, recent research with C3 grasses demonstrated that the Δ18O of leaf sucrose (Δ18OSuc, the parent substrate for cellulose synthesis) can be much higher than predicted from daytime Δ18O of leaf water (Δ18OLW), which could alter conclusions on photosynthetic versus post-photosynthetic effects on Δ18OCel via pex. Here, we assessed pex in leaves of perennial ryegrass (Lolium perenne) grown at different atmospheric relative humidity (RH) and CO2 levels, by determinations of Δ18OCel in leaves, Δ18OLGDZW (the Δ18O of water in the leaf growth-and-differentiation zone) and both Δ18OSuc and Δ18OLW (adjusted for εbio, the biosynthetic fractionation between water and carbohydrates) as alternative proxies for the substrate for cellulose synthesis. Δ18OLGDZW was always close to irrigation water, and pex was similar (0.53 ± 0.02 SE) across environments when determinations were based on Δ18OSuc. Conversely, pex was erroneously and variably underestimated (range 0.02-0.44) when based on Δ18OLW. The photosynthetic signal fraction in Δ18OCel is much more constant than hitherto assumed, encouraging leaf physiological reconstructions.
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Affiliation(s)
- Juan C Baca Cabrera
- Lehrstuhl für Grünlandlehre, Technische Universität München, Freising-Weihenstephan, Germany
- Forschungszentrum Jülich, Institute of Bio- and Geoscience, Agrosphere (IBG-3), Wilhelm-Johnen-Strasse, Jülich, Germany
| | - Regina T Hirl
- Lehrstuhl für Grünlandlehre, Technische Universität München, Freising-Weihenstephan, Germany
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Technische Universität München, Freising-Weihenstephan, Germany
- Crop Physiology Lab, Technische Universität München, Freising-Weihenstephan, Germany
| | - Jianjun Zhu
- Lehrstuhl für Grünlandlehre, Technische Universität München, Freising-Weihenstephan, Germany
| | - Hai Tao Liu
- College of Resources and Environment, Henan Agricultural University, Zhengzhou, China
| | - Xiao Ying Gong
- Key Laboratory for Subtropical Mountain Ecology, College of Geographical Sciences, Fujian Normal University, Fuzhou, China
| | - Jérôme Ogée
- INRAE, Bordeaux Sciences Agro, UMR ISPA, Villenave d'Ornon, France
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Technische Universität München, Freising-Weihenstephan, Germany
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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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Baca Cabrera JC, Hirl RT, Zhu J, Schäufele R, Ogée J, Schnyder H. 18 O enrichment of sucrose and photosynthetic and nonphotosynthetic leaf water in a C 3 grass-atmospheric drivers and physiological relations. PLANT, CELL & ENVIRONMENT 2023. [PMID: 37376738 DOI: 10.1111/pce.14655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 05/19/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023]
Abstract
The 18 O enrichment (Δ18 O) of leaf water affects the Δ18 O of photosynthetic products such as sucrose, generating an isotopic archive of plant function and past climate. However, uncertainty remains as to whether leaf water compartmentation between photosynthetic and nonphotosynthetic tissue affects the relationship between Δ18 O of bulk leaf water (Δ18 OLW ) and leaf sucrose (Δ18 OSucrose ). We grew Lolium perenne (a C3 grass) in mesocosm-scale, replicated experiments with daytime relative humidity (50% or 75%) and CO2 level (200, 400 or 800 μmol mol-1 ) as factors, and determined Δ18 OLW , Δ18 OSucrose and morphophysiological leaf parameters, including transpiration (Eleaf ), stomatal conductance (gs ) and mesophyll conductance to CO2 (gm ). The Δ18 O of photosynthetic medium water (Δ18 OSSW ) was estimated from Δ18 OSucrose and the equilibrium fractionation between water and carbonyl groups (εbio ). Δ18 OSSW was well predicted by theoretical estimates of leaf water at the evaporative site (Δ18 Oe ) with adjustments that correlated with gas exchange parameters (gs or total conductance to CO2 ). Isotopic mass balance and published work indicated that nonphotosynthetic tissue water was a large fraction (~0.53) of bulk leaf water. Δ18 OLW was a poor proxy for Δ18 OSucrose , mainly due to opposite Δ18 O responses of nonphotosynthetic tissue water (Δ18 Onon-SSW ) relative to Δ18 OSSW , driven by atmospheric conditions.
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Affiliation(s)
- Juan C Baca Cabrera
- Technische Universität München, TUM School of Life Sciences, Lehrstuhl für Grünlandlehre, Freising-Weihenstephan, Germany
- Forschungszentrum Jülich GmbH, Institute of Bio- and Geosciences, Agrosphere (IBG-3), Jülich, Germany
| | - Regina T Hirl
- Technische Universität München, TUM School of Life Sciences, Lehrstuhl für Grünlandlehre, Freising-Weihenstephan, Germany
| | - Jianjun Zhu
- Technische Universität München, TUM School of Life Sciences, Lehrstuhl für Grünlandlehre, Freising-Weihenstephan, Germany
| | - Rudi Schäufele
- Technische Universität München, TUM School of Life Sciences, Lehrstuhl für Grünlandlehre, Freising-Weihenstephan, Germany
| | | | - Hans Schnyder
- Technische Universität München, TUM School of Life Sciences, Lehrstuhl für Grünlandlehre, Freising-Weihenstephan, Germany
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Wadood SA, Jiang Y, Nie J, Li C, Rogers KM, Liu H, Zhang Y, Zhang W, Yuan Y. Effects of Light Shading, Fertilization, and Cultivar Type on the Stable Isotope Distribution of Hybrid Rice. Foods 2023; 12:foods12091832. [PMID: 37174370 PMCID: PMC10178473 DOI: 10.3390/foods12091832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/10/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023] Open
Abstract
The effect of fertilizer supply and light intensity on the distribution of elemental contents (%C and %N) and light stable isotopes (C, N, H, and O) in different rice fractions (rice husk, brown rice, and polished rice) of two hybrid rice cultivars (maintainer lines You-1B and Zhong-9B) were investigated. Significant variations were observed for δ13C (-31.3 to -28.3‱), δ15N (2.4 to 2.7‱), δ2H (-125.7 to -84.7‱), and δ18O (15.1‱ to 23.7‱) values in different rice fractions among different cultivars. Fertilizer treatments showed a strong association with %N, δ15N, δ2H, and δ18O values while it did not impart any significant variation for the %C and δ13C values. Light intensity levels also showed a significant influence on the isotopic values of different rice fractions. The δ13C values showed a positive correlation with irradiance. The δ2H and δ15N values decreased with an increase in the irradiance. The light intensity levels did not show any significant change for δ18O values in rice fractions. Multivariate ANOVA showed a significant interaction effect of different factors (light intensity, fertilizer concentration, and rice variety) on the isotopic composition of rice fractions. It is concluded that all environmental and cultivation factors mentioned above significantly influenced the isotopic values and should be considered when addressing the authenticity and origin of rice. Furthermore, care should be taken when selecting rice fractions for traceability and authenticity studies since isotopic signatures vary considerably among different rice fractions.
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Affiliation(s)
- Syed Abdul Wadood
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Hangzhou 310021, China
- Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Key Laboratory of Information Traceability for Agricultural Products, Ministry of Agriculture and Rural Affairs of China, Hangzhou 310021, China
- Department of Food Science, University of Home Economics Lahore, Lahore 54700, Pakistan
| | - Yunzhu Jiang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Hangzhou 310021, China
- Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Key Laboratory of Information Traceability for Agricultural Products, Ministry of Agriculture and Rural Affairs of China, Hangzhou 310021, China
| | - Jing Nie
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Hangzhou 310021, China
- Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Key Laboratory of Information Traceability for Agricultural Products, Ministry of Agriculture and Rural Affairs of China, Hangzhou 310021, China
| | - Chunlin Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Hangzhou 310021, China
- Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Key Laboratory of Information Traceability for Agricultural Products, Ministry of Agriculture and Rural Affairs of China, Hangzhou 310021, China
| | - Karyne M Rogers
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Hangzhou 310021, China
- Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Key Laboratory of Information Traceability for Agricultural Products, Ministry of Agriculture and Rural Affairs of China, Hangzhou 310021, China
- National Isotope Centre, GNS Science, 30 Gracefield Road, Lower Hutt 5040, New Zealand
| | - Hongyan Liu
- Research Center for Plants and Human Health, Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610213, China
| | - Yongzhi Zhang
- Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Key Laboratory of Information Traceability for Agricultural Products, Ministry of Agriculture and Rural Affairs of China, Hangzhou 310021, China
| | - Weixing Zhang
- China National Rice Research Institute, Hangzhou 310006, China
| | - Yuwei Yuan
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Hangzhou 310021, China
- Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Key Laboratory of Information Traceability for Agricultural Products, Ministry of Agriculture and Rural Affairs of China, Hangzhou 310021, China
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Arslan AM, Wang X, Liu BY, Xu YN, Li L, Gong XY. Photosynthetic resource-use efficiency trade-offs triggered by vapour pressure deficit and nitrogen supply in a C 4 species. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 197:107666. [PMID: 37001304 DOI: 10.1016/j.plaphy.2023.107666] [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: 09/29/2022] [Revised: 02/19/2023] [Accepted: 03/23/2023] [Indexed: 06/19/2023]
Abstract
Trade-offs in resource-use efficiency (including water-, nitrogen-, and light-use efficiency, i.e., WUE, NUE, and LUE) are an important acclimation strategy of plants to environmental stresses. C4 photosynthesis, featured by a CO2 concentrating mechanism, is believed to be more efficient in using resources compared to C3 photosynthesis. However, response of photosynthetic resource-use efficiency trade-offs in C4 plants to vapour pressure deficit (VPD) and N supply has rarely been studied. Here, we studied the photosynthetic acclimation of Cleistogenes squarrosa, a perennial C4 grass, to controlled growth conditions with high or low VPD and N supply. High VPD increased WUE by 12% and decreased NUE by 16%, the ratio of net photosynthetic rate (A) to electron transport rate (J) (A/J) by 7% and the apparent quantum yield by 6%. High N supply tended to reduce NUE and increased maximum phosphoenol pyruvate carboxylation rate by 71% and slightly increased WUE. Stomatal conductance showed acclimation to VPD according to the Ball-Berry model, while a balanced cost of carboxylation and transpiration capacity was found across VPD and N treatments based on the least-cost model. WUE correlated negatively with NUE and LUE indicating that there was a trade-off between them, which is likely associated with acclimations in stomatal conductance and CO2 concentrating mechanisms.
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Affiliation(s)
- Ashraf Muhammad Arslan
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Xuming Wang
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China; Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, Fujian Normal University, Fuzhou, 350007, China; Fujian Provincial Key Laboratory for Plant Eco-physiology, Fuzhou, 350007, China.
| | - Bo Ya Liu
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Yi Ning Xu
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Lei Li
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Xiao Ying Gong
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China; Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, Fujian Normal University, Fuzhou, 350007, China; Fujian Provincial Key Laboratory for Plant Eco-physiology, Fuzhou, 350007, China.
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Amitrano C, Junker A, D'Agostino N, De Pascale S, De Micco V. Integration of high-throughput phenotyping with anatomical traits of leaves to help understanding lettuce acclimation to a changing environment. PLANTA 2022; 256:68. [PMID: 36053378 PMCID: PMC9439985 DOI: 10.1007/s00425-022-03984-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 08/25/2022] [Indexed: 06/15/2023]
Abstract
MAIN CONCLUSION The combination of image-based phenotyping with in-depth anatomical analysis allows for a thorough investigation of plant physiological plasticity in acclimation, which is driven by environmental conditions and mediated by anatomical traits. Understanding the ability of plants to respond to fluctuations in environmental conditions is critical to addressing climate change and unlocking the agricultural potential of crops both indoor and in the field. Recent studies have revealed that the degree of eco-physiological acclimation depends on leaf anatomical traits, which show stress-induced alterations during organogenesis. Indeed, it is still a matter of debate whether plant anatomy is the bottleneck for optimal plant physiology or vice versa. Here, we cultivated 'Salanova' lettuces in a phenotyping chamber under two different vapor pressure deficits (VPDs; low, high) and watering levels (well-watered, low-watered); then, plants underwent short-term changes in VPD. We aimed to combine high-throughput phenotyping with leaf anatomical analysis to evaluate their capability in detecting the early stress signals in lettuces and to highlight the different degrees of plants' eco-physiological acclimation to the change in VPD, as influenced by anatomical traits. The results demonstrate that well-watered plants under low VPD developed a morpho-anatomical structure in terms of mesophyll organization, stomatal and vein density, which more efficiently guided the acclimation to sudden changes in environmental conditions and which was not detected by image-based phenotyping alone. Therefore, we emphasized the need to complement high-throughput phenotyping with anatomical trait analysis to unveil crop acclimation mechanisms and predict possible physiological behaviors after sudden environmental fluctuations due to climate changes.
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Affiliation(s)
- Chiara Amitrano
- Department of Agricultural Sciences, University of Naples Federico II, Portici, NA, Italy.
| | - Astrid Junker
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstr. 3, 06466, Seeland, Germany
| | - Nunzio D'Agostino
- Department of Agricultural Sciences, University of Naples Federico II, Portici, NA, Italy
| | - Stefania De Pascale
- Department of Agricultural Sciences, University of Naples Federico II, Portici, NA, Italy
| | - Veronica De Micco
- Department of Agricultural Sciences, University of Naples Federico II, Portici, NA, Italy
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Baca Cabrera JC, Hirl RT, Schäufele R, Macdonald A, Schnyder H. Stomatal conductance limited the CO 2 response of grassland in the last century. BMC Biol 2021; 19:50. [PMID: 33757496 PMCID: PMC7989024 DOI: 10.1186/s12915-021-00988-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/19/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The anthropogenic increase of atmospheric CO2 concentration (ca) is impacting carbon (C), water, and nitrogen (N) cycles in grassland and other terrestrial biomes. Plant canopy stomatal conductance is a key player in these coupled cycles: it is a physiological control of vegetation water use efficiency (the ratio of C gain by photosynthesis to water loss by transpiration), and it responds to photosynthetic activity, which is influenced by vegetation N status. It is unknown if the ca-increase and climate change over the last century have already affected canopy stomatal conductance and its links with C and N processes in grassland. RESULTS Here, we assessed two independent proxies of (growing season-integrating canopy-scale) stomatal conductance changes over the last century: trends of δ18O in cellulose (δ18Ocellulose) in archived herbage from a wide range of grassland communities on the Park Grass Experiment at Rothamsted (U.K.) and changes of the ratio of yields to the CO2 concentration gradient between the atmosphere and the leaf internal gas space (ca - ci). The two proxies correlated closely (R2 = 0.70), in agreement with the hypothesis. In addition, the sensitivity of δ18Ocellulose changes to estimated stomatal conductance changes agreed broadly with published sensitivities across a range of contemporary field and controlled environment studies, further supporting the utility of δ18Ocellulose changes for historical reconstruction of stomatal conductance changes at Park Grass. Trends of δ18Ocellulose differed strongly between plots and indicated much greater reductions of stomatal conductance in grass-rich than dicot-rich communities. Reductions of stomatal conductance were connected with reductions of yield trends, nitrogen acquisition, and nitrogen nutrition index. Although all plots were nitrogen-limited or phosphorus- and nitrogen-co-limited to different degrees, long-term reductions of stomatal conductance were largely independent of fertilizer regimes and soil pH, except for nitrogen fertilizer supply which promoted the abundance of grasses. CONCLUSIONS Our data indicate that some types of temperate grassland may have attained saturation of C sink activity more than one century ago. Increasing N fertilizer supply may not be an effective climate change mitigation strategy in many grasslands, as it promotes the expansion of grasses at the disadvantage of the more CO2 responsive forbs and N-fixing legumes.
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Affiliation(s)
- Juan C Baca Cabrera
- Technical University of Munich, Lehrstuhl für Grünlandlehre, Alte Akademie 12, 85354, Freising-Weihenstephan, Germany
| | - Regina T Hirl
- Technical University of Munich, Lehrstuhl für Grünlandlehre, Alte Akademie 12, 85354, Freising-Weihenstephan, Germany
| | - Rudi Schäufele
- Technical University of Munich, Lehrstuhl für Grünlandlehre, Alte Akademie 12, 85354, Freising-Weihenstephan, Germany
| | - Andy Macdonald
- Rothamsted Research, Sustainable Agriculture Sciences Department, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Hans Schnyder
- Technical University of Munich, Lehrstuhl für Grünlandlehre, Alte Akademie 12, 85354, Freising-Weihenstephan, Germany.
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Hirl RT, Ogée J, Ostler U, Schäufele R, Baca Cabrera JC, Zhu J, Schleip I, Wingate L, Schnyder H. Temperature-sensitive biochemical 18 O-fractionation and humidity-dependent attenuation factor are needed to predict δ 18 O of cellulose from leaf water in a grassland ecosystem. THE NEW PHYTOLOGIST 2021; 229:3156-3171. [PMID: 33251585 DOI: 10.1111/nph.17111] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 11/18/2020] [Indexed: 06/12/2023]
Abstract
We explore here our mechanistic understanding of the environmental and physiological processes that determine the oxygen isotope composition of leaf cellulose (δ18 Ocellulose ) in a drought-prone, temperate grassland ecosystem. A new allocation-and-growth model was designed and added to an 18 O-enabled soil-vegetation-atmosphere transfer model (MuSICA) to predict seasonal (April-October) and multi-annual (2007-2012) variation of δ18 Ocellulose and 18 O-enrichment of leaf cellulose (Δ18 Ocellulose ) based on the Barbour-Farquhar model. Modelled δ18 Ocellulose agreed best with observations when integrated over c. 400 growing-degree-days, similar to the average leaf lifespan observed at the site. Over the integration time, air temperature ranged from 7 to 22°C and midday relative humidity from 47 to 73%. Model agreement with observations of δ18 Ocellulose (R2 = 0.57) and Δ18 Ocellulose (R2 = 0.74), and their negative relationship with canopy conductance, was improved significantly when both the biochemical 18 O-fractionation between water and substrate for cellulose synthesis (εbio , range 26-30‰) was temperature-sensitive, as previously reported for aquatic plants and heterotrophically grown wheat seedlings, and the proportion of oxygen in cellulose reflecting leaf water 18 O-enrichment (1 - pex px , range 0.23-0.63) was dependent on air relative humidity, as observed in independent controlled experiments with grasses. Understanding physiological information in δ18 Ocellulose requires quantitative knowledge of climatic effects on pex px and εbio .
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Affiliation(s)
- Regina T Hirl
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, Freising-Weihenstephan, 85354, Germany
- UMR ISPA, INRAE, Villenave d'Ornon, 33140, France
| | - Jérôme Ogée
- UMR ISPA, INRAE, Villenave d'Ornon, 33140, France
| | - Ulrike Ostler
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, Freising-Weihenstephan, 85354, Germany
- Institut für Meteorologie und Klimaforschung, Atmosphärische Umweltforschung (IMK-IFU), Karlsruher Institut für Technologie (KIT), Kreuzeckbahnstraße 19, Garmisch-Partenkirchen, 82467, Germany
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, Freising-Weihenstephan, 85354, Germany
| | - Juan C Baca Cabrera
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, Freising-Weihenstephan, 85354, Germany
| | - Jianjun Zhu
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, Freising-Weihenstephan, 85354, Germany
| | - Inga Schleip
- Nachhaltige Grünlandnutzungssysteme und Grünlandökologie, Hochschule für nachhaltige Entwicklung Eberswalde, Schicklerstraße 5, Eberswalde, 16225, Germany
| | - Lisa Wingate
- UMR ISPA, INRAE, Villenave d'Ornon, 33140, France
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, Freising-Weihenstephan, 85354, Germany
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Baca Cabrera JC, Hirl RT, Zhu J, Schäufele R, Schnyder H. Atmospheric CO 2 and VPD alter the diel oscillation of leaf elongation in perennial ryegrass: compensation of hydraulic limitation by stored-growth. THE NEW PHYTOLOGIST 2020; 227:1776-1789. [PMID: 32369620 DOI: 10.1111/nph.16639] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 04/26/2020] [Indexed: 06/11/2023]
Abstract
We explored the effects of atmospheric CO2 concentration (Ca ) and vapor pressure deficit (VPD) on putative mechanisms controlling leaf elongation in perennial ryegrass. Plants were grown in stands at a Ca of 200, 400 or 800 μmol mol-1 combined with high (1.17 kPa) or low (0.59 kPa) VPD during the 16 h-day in well-watered conditions with reduced nitrogen supply. We measured day : night-variation of leaf elongation rate (LERday : LERnight ), final leaf length and width, epidermal cell number and length, stomatal conductance, transpiration, leaf water potential and water-soluble carbohydrates and osmotic potential in the leaf growth-and-differentiation zone (LGDZ). Daily mean LER or morphometric parameters did not differ between treatments, but LERnight strongly exceeded LERday , particularly at low Ca and high VPD. Across treatments LERday was negatively related to transpiration (R2 = 0.75) and leaf water potential (R2 = 0.81), while LERnight was independent of leaf water potential or turgor. Enhancement of LERnight over LERday was proportional to the turgor-change between day and night (R2 = 0.93). LGDZ sugar concentration was high throughout diel cycles, providing no evidence of source limitation in any treatment. Our data indicate a mechanism of diel cycling between daytime hydraulic and night-time stored-growth controls of LER, buffering Ca and daytime VPD effects on leaf elongation.
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Affiliation(s)
- Juan C Baca Cabrera
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, Freising-Weihenstephan, 85354, Germany
| | - Regina T Hirl
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, Freising-Weihenstephan, 85354, Germany
| | - Jianjun Zhu
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, Freising-Weihenstephan, 85354, Germany
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, Freising-Weihenstephan, 85354, Germany
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, Freising-Weihenstephan, 85354, Germany
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10
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Yang F, Schäufele R, Liu HT, Ostler U, Schnyder H, Gong XY. Gross and net nitrogen export from leaves of a vegetative C 4 grass. JOURNAL OF PLANT PHYSIOLOGY 2020; 244:153093. [PMID: 31841951 DOI: 10.1016/j.jplph.2019.153093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/31/2019] [Accepted: 11/29/2019] [Indexed: 06/10/2023]
Abstract
Nitrogen (N) mobilization from mature leaves plays a key role in supplying amino acids to vegetative and reproductive sinks. However, it is unknown if the mobilized N is predominantly sourced by net N-export (a senescence-related process) or other source of N-export from leaves. We used a new approach to partition gross and net N-export from leaf blades at different developmental stages in Cleistogenes squarrosa (a perennial C4 grass). Net N-export was determined as net loss of leaf N with age, while gross N-export was quantified from isotopic mass balances obtained following 24 h-long 15N-labeling with nitrate on 10-12 developmentally distinct (mature and senescing) leaves of individual major tillers. Net N-export was apparent only in older leaves (leaf no. > 7, with leaves numbered basipetally from the tip of the tiller and leaf no. 2 the youngest fully-expanded leaf), while gross N-export was largely independent of leaf age category and was ∼8.4 times greater than the net N-export of a tiller. At whole-tiller level, N import compensated 88 ± 14 (SE) % of gross N-export of all mature blades leading to a net N-export of 0.51 ± 0.07 (SE) μg h-1 tiller-1. N-import was equivalent to 0.09 ± 0.01 (SE) d-1 of total leaf N, similar to reported rates of leaf protein turnover. Gross N-export from all mature blades of a tiller was ∼1.9-times the total demand of the immature tissues of the same (vegetative) tiller. Significant N-export is evident in all mature blades, and is not limited to senescence conditions, implying a much shorter mean residence time of leaf N than that calculated from net N-export. Gross N-export contributes not only to the N demand of the immature tissues of the same tiller but also to N supply of other sinks, such as newly formed tillers. N dynamics at tiller level is integrated with that of the remainder of the shoot, thus highlights the importance of integration of leaf-, tiller-, and plant-scale N dynamics.
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Affiliation(s)
- Fang Yang
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany
| | - Rudi Schäufele
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany
| | - Hai Tao Liu
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany
| | - Ulrike Ostler
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany
| | - Hans Schnyder
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany
| | - Xiao Ying Gong
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany.
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11
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Chen G, Sun LZ, Auerswald K. Effects of Wilting and Dew on the Water Isotope Composition of Detached Grass in Temperate Grassland. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:9460-9467. [PMID: 31381328 DOI: 10.1021/acs.jafc.9b02978] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Understanding the water isotopes in feed products derived from grass is fundamental for tracing domestic animal products. Grass silage water was reported to have fewer heavy isotopes than fresh grass, but it is still unknown whether dew formation (either dewfall or dewrise), exchange with soil water, or other processes override the expected enrichment of heavy isotopes due to wilting. The isotopic variations of water (δ2H, δ18O) in fresh grass and cut grass during wilting on soil and on plastic were compared in this study. Drying enriched heavier isotopes, but this was overridden by three processes that finally caused low δ2H and δ18O values: (i) the adsorption of humidity from the surroundings, (ii) the exchange with humidity, and (iii) the depletion of heavy water isotopes close to organic surfaces, called the surface effect, which was the most dominant effect at the end of drying when the water content became low.
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Affiliation(s)
- Guo Chen
- College of Earth Science , Chengdu University of Technology , Chengdu 610059 , Sichuan , People's Republic of China
- Lehrstuhl für Grünlandlehre , Technische Universität München , Alte Akademie 12 , Freising-Weihenstephan 85354 , Germany
| | - Luan Zi Sun
- Lehrstuhl für Grünlandlehre , Technische Universität München , Alte Akademie 12 , Freising-Weihenstephan 85354 , Germany
- College of Grassland Agriculture , Northwest A&F University , Yangling , Shaanxi 712100 , People's Republic of China
| | - Karl Auerswald
- Lehrstuhl für Grünlandlehre , Technische Universität München , Alte Akademie 12 , Freising-Weihenstephan 85354 , Germany
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12
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Gerlein-Safdi C, Gauthier PPG, Sinkler CJ, Caylor KK. Leaf water 18 O and 2 H maps show directional enrichment discrepancy in Colocasia esculenta. PLANT, CELL & ENVIRONMENT 2017; 40:2095-2108. [PMID: 28658718 DOI: 10.1111/pce.13002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Revised: 05/31/2017] [Accepted: 06/02/2017] [Indexed: 06/07/2023]
Abstract
Spatial patterns of leaf water isotopes are challenging to predict because of the intricate link between vein and lamina water. Many models have attempted to predict these patterns, but to date, most have focused on monocots with parallel veins. These provide a simple system to study, but do not represent the majority of plant species. Here, a new protocol is developed using a Picarro induction module coupled to a cavity ringdown spectrometer to obtain maps of the leaf water isotopes (18 O and 2 H). The technique is applied to Colocasia esculenta leaves. The results are compared with isotope ratio mass spectrometry. In C. esculenta, a large enrichment in the radial direction is observed, but not in the longitudinal direction. The string-of-lakes model fails to predict the observed patterns, while the Farquhar-Gan model is more successful, especially when enrichment is accounted for along the radial direction. Our results show that reticulate-veined leaves experience a larger enrichment along the axis of the secondary veins than along the midrib. We hypothesize that this is due to the lower major/minor vein ratio that leads to longer pathways between major veins and sites of evaporation.
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Affiliation(s)
- Cynthia Gerlein-Safdi
- Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Paul P G Gauthier
- Department of Geosciences, Princeton University, Princeton, NJ, 08544, USA
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Craig James Sinkler
- Department of Geological, Environmental, and Marine Sciences, Rider University, Lawrenceville, NJ, 08648, USA
- EarthRes Group Inc., Pipersville, PA, 18947, USA
| | - Kelly Krispin Caylor
- Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, 08544, USA
- Department of Geography, UC Santa Barbara, Santa Barbara, CA, 93106, USA
- Bren School of Environmental Science and Management, UC Santa Barbara, Santa Barbara, CA, 93106, USA
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Chen G, Schäufele R, Auerswald K. Ambient Conditions and Feeding Strategy Influence δ 18O of Milk Water in Cows (Bos taurus). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:7387-7395. [PMID: 28780863 DOI: 10.1021/acs.jafc.7b02482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
There are increasing concerns by consumers regarding agricultural product traceability and authenticity. Oxygen isotope composition (δ18O) has been used in this context based on the relationship between δ18O of animal products and annual precipitation. However, in dairy products this relationship is affected by the seasonality of δ18O in milk water which in turn depends on the feeding system used. We measured 608 milk samples from 28 farms with various feeding strategies in southern Germany throughout the year, investigating the influences of ambient conditions, drinking water source, and feeding strategies on seasonal variation of δ18O in milk water (δmilk). The mechanistic Munich-Kohn model reflecting these influences predicted the seasonal and farm-specific variation of δmilk well. The relationship between δ18O of precipitation and δmilk varied in different feeding strategies. The interplay of ambient conditions and feeding strategy on δmilk should thus be carefully considered when identifying the origin of milk.
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Affiliation(s)
- Guo Chen
- Lehrstuhl für Grünlandlehre, Technische Universität München , Alte Akademie 12, Freising-Weihenstephan 85354, Germany
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Technische Universität München , Alte Akademie 12, Freising-Weihenstephan 85354, Germany
| | - Karl Auerswald
- Lehrstuhl für Grünlandlehre, Technische Universität München , Alte Akademie 12, Freising-Weihenstephan 85354, Germany
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14
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Lehmann MM, Gamarra B, Kahmen A, Siegwolf RTW, Saurer M. Oxygen isotope fractionations across individual leaf carbohydrates in grass and tree species. PLANT, CELL & ENVIRONMENT 2017; 40:1658-1670. [PMID: 28436078 DOI: 10.1111/pce.12974] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Revised: 04/12/2017] [Accepted: 04/14/2017] [Indexed: 06/07/2023]
Abstract
Almost no δ18 O data are available for leaf carbohydrates, leaving a gap in the understanding of the δ18 O relationship between leaf water and cellulose. We measured δ18 O values of bulk leaf water (δ18 OLW ) and individual leaf carbohydrates (e.g. fructose, glucose and sucrose) in grass and tree species and δ18 O of leaf cellulose in grasses. The grasses were grown under two relative humidity (rH) conditions. Sucrose was generally 18 O-enriched compared with hexoses across all species with an apparent biosynthetic fractionation factor (εbio ) of more than 27‰ relative to δ18 OLW , which might be explained by isotopic leaf water and sucrose synthesis gradients. δ18 OLW and δ18 O values of carbohydrates and cellulose in grasses were strongly related, indicating that the leaf water signal in carbohydrates was transferred to cellulose (εbio = 25.1‰). Interestingly, damping factor pex px , which reflects oxygen isotope exchange with less enriched water during cellulose synthesis, responded to rH conditions if modelled from δ18 OLW but not if modelled directly from δ18 O of individual carbohydrates. We conclude that δ18 OLW is not always a good substitute for δ18 O of synthesis water due to isotopic leaf water gradients. Thus, compound-specific δ18 O analyses of individual carbohydrates are helpful to better constrain (post-)photosynthetic isotope fractionation processes in plants.
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Affiliation(s)
- Marco M Lehmann
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), Villigen, CH-5232, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Bruno Gamarra
- Institute of Agricultural Sciences, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Ansgar Kahmen
- Department of Environmental Sciences - Botany, University of Basel, Basel, CH-4056, Switzerland
| | - Rolf T W Siegwolf
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), Villigen, CH-5232, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Matthias Saurer
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), Villigen, CH-5232, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
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15
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Liu HT, Schäufele R, Gong XY, Schnyder H. The δ 18 O and δ 2 H of water in the leaf growth-and-differentiation zone of grasses is close to source water in both humid and dry atmospheres. THE NEW PHYTOLOGIST 2017; 214:1423-1431. [PMID: 28369914 DOI: 10.1111/nph.14549] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Accepted: 03/06/2017] [Indexed: 06/07/2023]
Abstract
The oxygen and hydrogen isotope composition of water in the leaf growth-and-differentiation zone, LGDZ, (δ18 OLGDZ , δ2 HLGDZ ) of grasses influences the isotopic composition of leaf cellulose (oxygen) and wax (hydrogen) - important for understanding (paleo)environmental and physiological information contained in these biological archives - but is presently unknown. This work determined δ18 OLGDZ and δ2 HLGDZ , 18 O- and 2 H-enrichment of LGDZ (∆18 OLGDZ and ∆2 HLGDZ ), and the 18 O- and 2 H-enrichment of leaf blade water (∆18 OLW, ∆2 HLW ) in two C3 and three C4 grasses grown at high and low vapor pressure deficit (VPD). The proportion of unenriched water (px ) in the LGDZ ranged from 0.9 to 1.0 for 18 O and 1.0 to 1.2 for 2 H. VPD had no effect on the proportion of 18 O- and 2 H-enriched water in the LGDZ, and species effects were small or nonsignificant. Deuterium discrimination caused depletion of 2 H in LGDZ water, increasing (apparent) px -values > 1.0 in some cases. The isotopic composition of water in the LGDZ was close to that of source water, independent of VPD and much less enriched than previously supposed, but similar to reported xylem water in trees. The well-constrained px will be useful in future investigations of oxygen and hydrogen isotopic fractionation during cellulose and wax synthesis, respectively.
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Affiliation(s)
- Hai Tao Liu
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354, Freising-Weihenstephan, Germany
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354, Freising-Weihenstephan, Germany
| | - Xiao Ying Gong
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354, Freising-Weihenstephan, Germany
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354, Freising-Weihenstephan, Germany
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Yang F, Gong XY, Liu HT, Schäufele R, Schnyder H. Effects of nitrogen and vapour pressure deficit on phytomer growth and development in a C4 grass. AOB PLANTS 2017; 8:plw075. [PMID: 27810947 PMCID: PMC5206350 DOI: 10.1093/aobpla/plw075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 10/19/2016] [Indexed: 05/12/2023]
Abstract
Phytomers are basic morphological units of plants. Knowledge of phytomer development is essential for understanding morphological plasticity, functional-structural modelling of plant growth and the usage of leaf characteristics to indicate growth conditions at the time of production (e.g. stable isotope signals). Yet, systematic analysis on the process of phytomer development is unavailable for wild or perennial C4 grasses. Also, effects of environmental factors, such as nitrogen nutrition or vapour pressure deficit (VPD), on coordination events of developmental processes of C4 grasses have not been studied. This study investigates phytomer growth and development in Cleistogenes squarrosa, a predominant C4 grass in the Eurasian steppe, grown at low (0.63 kPa) or high (1.58 kPa) VPD with low or high nitrogen supply in controlled environments. Elongation of phytomers on marked tillers was measured daily for 13 days. Then lengths of immature and mature phytomer components (blade, sheath and internode) of all phytomers were measured following dissection. Nitrogen nutrition and VPD had no effects on coordination of growth within and between phytomers: phytomer tips emerged when phytomers reached 26 % of their final length, coincident with the acceleration phase of its elongation; blade elongation stopped when phytomers reached ∼75 % of their final length and elongation of the preceding phytomer was confined to the internode. The relationship between fraction of final phytomer length and days after tip emergence for all treatments was well described by a sigmoidal function: y = 1/{1 + exp[(1.82 - x)/1.81]}. C. squarrosa exhibited little morphological plasticity at phytomer-level in response to nitrogen supply and VPD, but a clear increase in tillering under high N supply. Also, the invariant coordination of elongation within and between phytomers was a stable developmental feature, thus the quantitative coordination rules are applicable for predicting morphological development of C. squarrosa under contrasting levels of nitrogen nutrition or VPD.
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Affiliation(s)
- Fang Yang
- Lehrstuhl für Grünlandlehre, Department für Pflanzenwissenschaften, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Xiao Ying Gong
- Lehrstuhl für Grünlandlehre, Department für Pflanzenwissenschaften, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Hai Tao Liu
- Lehrstuhl für Grünlandlehre, Department für Pflanzenwissenschaften, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Department für Pflanzenwissenschaften, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Department für Pflanzenwissenschaften, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
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17
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Gong XY, Schäufele R, Schnyder H. Bundle-sheath leakiness and intrinsic water use efficiency of a perennial C4 grass are increased at high vapour pressure deficit during growth. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:321-333. [PMID: 27864539 PMCID: PMC5853292 DOI: 10.1093/jxb/erw417] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 10/20/2016] [Indexed: 05/05/2023]
Abstract
Bundle-sheath leakiness (ϕ) is a key parameter of the CO2-concentrating mechanism of C4 photosynthesis and is related to leaf-level intrinsic water use efficiency (WUEi). This work studied short-term dynamic responses of ϕ to alterations of atmospheric CO2 concentration in Cleistogenes squarrosa, a perennial grass, grown at high (1.6 kPa) or low (0.6 kPa) vapour pressure deficit (VPD) combined with high or low N supply in controlled environment experiments. ϕ was determined by concurrent measurements of photosynthetic gas exchange and on-line carbon isotope discrimination, using a new protocol. Growth at high VPD led to an increase of ϕ by 0.13 and a concurrent increase of WUEi by 14%, with similar effects at both N levels. ϕ responded dynamically to intercellular CO2 concentration (C i), increasing with C i Across treatments, ϕ was negatively correlated to the ratio of CO2 saturated assimilation rate to carboxylation efficiency (a proxy of the relative activities of Rubisco and phosphoenolpyruvate carboxylase) indicating that the long-term environmental effect on ϕ was related to the balance between C3 and C4 cycles. Our study revealed considerable dynamic and long-term variation in ϕ of C. squarrosa, suggesting that ϕ should be determined when carbon isotope discrimination is used to assess WUEi Also, the data indicate a trade-off between WUEi and energetic efficiency in C. squarrosa.
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Affiliation(s)
- Xiao Ying Gong
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354 Freising, Germany
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354 Freising, Germany
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354 Freising, Germany
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