Skip to main content
SpringerLink
Log in

Explorations into the Physiology and Ecology of Grassland Plants and Ecosystems: One Agronomist’s Academic Journey

  • Chapter
  • First Online:
Progress in Botany Vol. 84

Part of the book series: Progress in Botany ((BOTANY,volume 84))

  • 116 Accesses

Abstract

This review gives an account of one agronomists’ and his teams’ contribution to the understanding of some aspects of the physiology and ecology of grassland plants and ecosystems. The topics span across multiple spatial and temporal scales, from the cellular basis of leaf growth in grasses, to functional components of CO2 exchange at leaf to ecosystem scale, the role of carbohydrate (fructan) stores in recycling of sucrose and supporting respiration and vegetative and reproductive growth in benign and stressful conditions, the multi-seasonal 18O-ecohydrology of a pasture, last-century climate change effects on intrinsic water-use efficiency and canopy-integrated stomatal conductance of a range of grassland communities with contrasting nutrient status and plant functional group composition, regional scale changes of the C4/C3 abundance ratio in Inner Mongolia grassland, to ecological fingerprints of cattle based agroecosystems derived from the stable isotope composition of animal tissues, such as hair and milk. Much of the research relied on the development or improvement of methodology, including stable isotope techniques, encompassing 13CO2/12CO2 gas exchange and dynamic (or steady-state) labelling systems from leaf-scale in controlled conditions to ecosystem-scale in natural environments, analysis of tracer kinetics with compartmental models, and interpretations of natural isotope signals in biomass (13C/12C, 15N/14N, 18O/16O) or water pools (18O/16O, 2H/1H) of soil, vegetation, and animals.

Communicated by Ulrich Lüttge and Hans Pretzsch

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Log in via an institution
Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 149.00
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Hardcover Book
USD 199.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

Notes

  1. 1.

    Not everyone acknowledged the importance of research on grass growth, however. A short while after we had returned to Bonn from Columbia, at some social gathering with many people I did not know, I ran into someone who liked to know what I was researching. When I responded: ‘I try to understand how the grass grows’, he seemed to be slightly offended, stating he had asked a serious question. Later, Monika Kavanová told me, that travelling through the Argentinian Pampa one could easily find one-self listening to a radio show on grass growth. Different places, different people, different interests!

  2. 2.

    δ13C = Rsample/Rstandard – 1, and Rsample the 13C/12C abundance ratio in the sample and Rstandard in the international standard, Vienna Pee Dee Belemnite.

  3. 3.

    Δ13C = (δ13CCO2 – δ13CP)/(1 – δ13CP), with δ13CP the δ13C of the photosynthetic product.

  4. 4.

    Severe acute respiratory syndrome coronavirus.

References

  • Ainsworth EA, Long SP (2005) What have we learned from 15 years of free-air CO2 enrichment (FACE)? A meta-analytic review of the responses of photosynthesis, canopy properties and plant production to rising CO2. New Phytol 165:351–372

    PubMed  Google Scholar 

  • Ambrose SH, DeNiro MJ (1986) The isotopic ecology of East African mammals. Oecologia 69:395–406

    PubMed  Google Scholar 

  • Arredondo JT, Schnyder H (2003) Components of leaf elongation rate and their relationship to specific leaf area in contrasting grasses. New Phytol 158:305–314

    Google Scholar 

  • Auerswald K, Wittmer MHOM, Männel TT, Bai YF, Schäufele R, Schnyder H (2009) Large regional-scale variation in C3/C4 distribution patterns of Inner Mongolia steppe is revealed by grazer wool carbon isotope composition. Biogeosciences 6:795–805

    Google Scholar 

  • Auerswald K, Wittmer MHOM, Zazzo A, Schäufele R, Schnyder H (2010) Biases in the analysis of stable isotope discrimination in food webs. J Appl Ecol 47(4):936–941. https://doi.org/10.1111/jpe.2010.47.issue-4. https://doi.org/10.1111/j.1365-2664.2009.01764.x

  • Auerswald K, Rossmann A, Schäufele R, Schwertl M, Monahan FJ, Schnyder H (2011) Does natural weathering change the stable isotope composition (2H, 13C, 15N, 18O, 34S) of cattle hair? Rapid Commun Mass Spectrom 25:3741–3748

    PubMed  Google Scholar 

  • Auerswald K, Wittmer MHOM, Bai YF, Yang H, Taube F, Susenbeth A, Schnyder H (2012) C4 abundance in an Inner Mongolia grassland system is driven by temperature-moisture interaction, not grazing pressure. Basic Appl Ecol 13:67–75

    Google Scholar 

  • Austin RB, Edrich JA, Ford MA, Blackwell RD (1977) The fate of the dry matter, carbohydrates and 14C lost from the leaves and stems of wheat during grain filling. Ann Bot 41:1309–1321

    Google Scholar 

  • Baca Cabrera JC, Hirl RT, Zhu JJ, Schäufele R, Schnyder H (2020) Atmospheric CO2 and VPD alter the diel oscillation of leaf elongation in perennial ryegrass: compensation of hydraulic limitation by stored-growth. New Phytol 227:1776–1789

    PubMed  Google Scholar 

  • Baca Cabrera JC, Hirl RT, Schäufele R, Macdonald A, Schnyder (2021a) Stomatal conductance limited the CO2 response of grassland in the last century. BMC Biol 19:50

    PubMed  PubMed Central  Google Scholar 

  • Baca Cabrera JC, Hirl RT, Schäufele R, Zhu J, Liu H, Ogée J, Schnyder H (2021b) 18O enrichment of leaf cellulose correlated with 18O enrichment of leaf sucrose but not bulk leaf water in a C3 grass across contrasts of atmospheric CO2 concentration and air humidity. ResearchSquare. https://doi.org/10.21203/rs.3.rs-596094/v1

  • Baca Cabrera JC, Hirl RT, Zhu JJ, Schäufele R, Ogée J, Schnyder H (2022) 18O enrichment of sucrose and photosynthetic and non-photosynthetic leaf water in a C3 grass – atmospheric drivers and physiological relations. Authored. 14 Sept 2022. https://doi.org/10.22541/au.166313352.24737127/v1

  • Barbosa ICR, Kley M, Schäufele R, Auerswald K, Schröder W, Filli F, Hertwig S, Schnyder H (2009) Analysing the isotopic life history of alpine ungulates Capra ibex and Rupicapra rupicapra rupicapra through their horns. Rapid Commun Mass Spectrom 23:2347–2356

    PubMed  Google Scholar 

  • Barbosa ICR, Köhler IH, Auerswald K, Lüps P, Schnyder H (2010) Last-century changes of alpine grassland water-use efficiency: a reconstruction through carbon isotope analysis of a time-series of Capra ibex horns. Glob Chang Biol 16:1171–1180

    Google Scholar 

  • Barbour MM (2007) Stable oxygen isotope composition of plant tissue: a review. Funct Plant Biol 34:83–94

    PubMed  Google Scholar 

  • Barbour MM, Farquhar GD (2000) Relative humidity- and ABA-induced variation in carbon and oxygen isotope ratios of cotton leaves. Plant Cell Environ 23:473–485

    Google Scholar 

  • Barrie A, Bricout J, Koziet J (1984) Gas chromatography-stable isotope ratio analysis at natural abundance levels. Biomed Mass Spectrom 11:583–588

    Google Scholar 

  • Braun A, Auerswald K, Vikari A, Schnyder H (2013a) Dietary protein content affects isotopic carbon and nitrogen turnover. Rapid Commun Mass Spectrom 27:2676–2684

    PubMed  Google Scholar 

  • Braun A, Schneider S, Auerswald K, Bellof G, Schnyder H (2013b) Forward modeling of fluctuating dietary 13C signals to validate 13C turnover models of milk and milk components from a diet-switch experiment. PloS One 8. https://doi.org/10.1371/journal.pone.0085235

  • Busch FA (2020) Photorespiration in the context of Rubisco biochemistry, CO2 diffusion and metabolism. Plant J 101:919–939

    PubMed  Google Scholar 

  • Camin F, Boner M, Bontempo L, Fauhl-Hassek C, Kelly SD, Riedl J, Rossmann A (2017) Stable isotope techniques for verifying the declared geographic origin of food in legal cases. Trends Food Sci Technol 61:176–187

    Google Scholar 

  • Casas C, Gundel PE, Deliens E, Iannone LJ, Martinez GG, Vignale MV, Schnyder H (2022) Loss of fungal symbionts at the arid limit of the distribution range in a native Patagonian grass—resource eco-physiological relations. Funct Ecol 36:583–594

    Google Scholar 

  • Cerling TE, Barnette JE, Bowen GJ, Chesson LA, Ehleringer JR, Remien CH, Shea P, Tripple BJ, West JB (2016) Forensic stable isotope biogeochemistry. Annu Rev Earth Planet Sci 44:175–206

    Google Scholar 

  • Cernusak LA, Wong SC, Farquhar GD (2003) Oxygen isotope composition of phloem sap in relation to leaf water in Ricinus communis. Funct Plant Biol 30:1059–1070

    PubMed  Google Scholar 

  • Cernusak LA, Farquhar GD, Pate JS (2005) Environmental and physiological controls over oxygen and carbon isotope composition of Tasmanian blue gum, Eucalyptus globulus. Tree Physiol 25:129–146

    PubMed  Google Scholar 

  • Cernusak LA, Barbeta A, Bush RT, Eichstaedt (Bögelein) R, Ferrio JP, Flanagan LB, Gessler A, Martín-Gómez P, Hirl RT, Kahmen A, Keitel C, Lai C-T, Munksgaard NC, Nelson DB, Ogée J, Roden JS, Schnyder H, Voelker SL, Wang L, Stuart-Williams H, Wingate L, Yu W, Zhao L, Cuntz M (2022) Do 2H and 18O in leaf water reflect environmental drivers differently? New Phytol 235:41–51

    PubMed  PubMed Central  Google Scholar 

  • Chen G, Schnyder H, Auerswald K (2017) Model explanation of the seasonal variation of δ18O in cow (Bos taurus) hair under temperate conditions. Sci Rep 7:320

    PubMed  PubMed Central  Google Scholar 

  • Chollet R, Ogren WL (1975) Regulation of photorespiration in C3 and C4 species. Bot Rev 41:137–179

    Google Scholar 

  • Collatz GJ, Berry JA, Clark JS (1998) Effects of climate and atmospheric CO2 partial pressure on the global distribution of C4 grasses: present, past, and future. Oecologia 114:441–454

    PubMed  Google Scholar 

  • Cornwell WK, Wright IJ, Turner J, Maire V, Barbour MM, Cernusak LA, Dawson T, Ellsworth D, Farquhar GD, Griffiths H, Keitel C, Knohl A, Reich PB, Williams DG, Bhaskar R, Cornelissen JHC, Richards A, Schmidt S, Valladares F, Körner C, Schulze E-D, Buchmann N, Santiago LS (2018) Climate and soils together regulate photosynthetic carbon isotope discrimination within C3 plants worldwide. Glob Ecol Biogeogr 27:1056–1067

    Google Scholar 

  • De Visser R, Vianden H, Schnyder H (1997) Kinetics and relative significance of remobilized and current C and N incorporation in leaf and root growth zones of Lolium perenne after defoliation: assessment by 13C and 15N steady-state labelling. Plant Cell Environ 20:37–46

    Google Scholar 

  • De Visser SN, Freymann BP, Schnyder H (2008) Trophic interactions among invertebrates in termitaria in the African savanna: a stable isotope approach. Ecol Entomol 33:758–764

    Google Scholar 

  • Déléens E, Pavlidès D, Queiroz O (1983) Application du traçage isotopique naturel par le 13C à la mesure du renouvellement de la matière foliaire chez les plantes en C3. Physiol Vég 21:723–729

    Google Scholar 

  • Déléens E, Gregory N, Bourdu R (1984) Transition between seed reserves use and photosynthetic supply during development of maize seedlings. Plant Sci Lett 37:35–39

    Google Scholar 

  • DeNiro MJ, Epstein S (1979) Relationship between the oxygen isotope ratios of terrestrial plant cellulose, carbon dioxide, and water. Science 204:51–53

    PubMed  Google Scholar 

  • Durand J-L, Onillon B, Schnyder H, Rademacher I (1995) Drought effects on cellular and spatial parameters of leaf growth in tall fescue. J Exp Bot 46:1147–1115

    Google Scholar 

  • Farquhar GD, Richards RA (1984) Isotopic composition of plant carbon correlates with water-use efficiency in wheat genotypes. Aust J Plant Physiol 11:539–552

    Google Scholar 

  • Farquhar GD, von Caemmerer S, Berry JA (1980) A biochemical model of photosynthetic CO2 assimilation in leaves of C3 species. Planta 149:78–90

    PubMed  Google Scholar 

  • Farquhar GD, O’Leary MH, Berry JA (1982) On the relationship between carbon isotope discrimination and the intercellular carbon dioxide concentration in leaves. Funct Plant Biol 9:121–137

    Google Scholar 

  • Farquhar GD, Ehleringer JR, Hubick KT (1989) Carbon isotope discrimination and photosynthesis. Annu Rev Plant Physiol Plant Mol Biol 40:503–537

    Google Scholar 

  • Farrar JF (1980) Allocation of carbon to growth, storage and respiration in the vegetative barley plant. Plant Cell Environ 3:97–105

    Google Scholar 

  • Fondy BR, Geiger DR (1982) Diurnal pattern of translocation and carbohydrate metabolism in source leaves of Beta vulgaris L. Plant Physiol 70:671–676

    PubMed  PubMed Central  Google Scholar 

  • Francey RJ, Farquhar GD (1982) An explanation of 13C/12C variations in tree rings. Nature 297:28–31

    Google Scholar 

  • Gallagher JN, Biscoe PV, Scott RK (1975) Barley and its environment. Stability of grain weight. J Appl Ecol 12:319–336

    Google Scholar 

  • Gamnitzer U, Schäufele R, Schnyder H (2009) Observing 13C labeling kinetics in CO2 respired by a temperate grassland ecosystem. New Phytol 184:376–386

    PubMed  Google Scholar 

  • Gamnitzer U, Moyes AB, Bowling DR, Schnyder H (2011) Measuring and modelling the isotopic composition of soil respiration: insights from a grassland tracer experiment. Biogeosciences 8:1333–1350

    Google Scholar 

  • Gastal F, Nelson CJ (1994) Nitrogen use within the growing leaf blade of tall fescue. Plant Physiol 105:191–197

    PubMed  PubMed Central  Google Scholar 

  • Gebbing T, Schnyder H (1999) Pre-anthesis reserve utilization for protein and carbohydrate synthesis in grains of wheat. Plant Physiol 121:871–878

    PubMed  PubMed Central  Google Scholar 

  • Gebbing T, Schnyder H, Kühbauch W (1998) Carbon mobilization in shoot parts and roots of wheat during grain filling: assessment by 13C/12C steady-state labelling, growth analysis and balance sheets of reserves. Plant Cell Environ 21:301–313

    Google Scholar 

  • Gebbing T, Schnyder H, Kühbauch W (1999) The utilization of pre-anthesis reserves in grain filling of wheat: assessment by 13C/12C steady-state labelling. Plant Cell Environ 22:857–858

    Google Scholar 

  • Geiger DR (1980) Measurement of translocation. Methods Enzymol 69:561–571

    Google Scholar 

  • Geist J, Auerswald K, Boom A (2005) Stable carbon isotopes in freshwater mussel shells: environmental record or marker for metabolic activity? Geochim Cosmochim Acta 69:3545–3554

    Google Scholar 

  • Gong XY, Chen Q, Lin S, Brueck H, Dittert K, Taube F, Schnyder H (2011) Tradeoffs between nitrogen- and water-use efficiency in dominant species of the semiarid steppe of Inner Mongolia. Plant Soil 340(1–2):227–238. https://doi.org/10.1007/s11104-010-0525-9

    Article  Google Scholar 

  • Gong XY, Schäufele R, Feneis W, Schnyder H (2015) 13CO2/12CO2 exchange fluxes in a clamp-on leaf cuvette: disentangling artefacts and flux components. Plant Cell Environ 38:2417–2432

    PubMed  Google Scholar 

  • Gong XY, Schäufele R, Lehmeier CA, Tcherkez G, Schnyder H (2017) Atmospheric CO2 mole fraction affects stand-scale carbon use efficiency of sunflower by stimulating respiration in light. Plant Cell Environ 40:401–412

    PubMed  Google Scholar 

  • Gong XY, Tcherkez G, Wenig J, Schäufele R, Schnyder H (2018) Determination of leaf respiration in the light: comparison between an isotopic disequilibrium method and the Laisk method. New Phytol 218:1371–1382

    PubMed  Google Scholar 

  • Gordon AJ, Ryle GYA, Webb G (1980) The relationship between sucrose and starch during ‘dark’ export from leaves of uniculm barley. J Exp Bot 31:845–850

    Google Scholar 

  • Grimoldi AA, Kavanová M, Lattanzi FA, Schnyder H (2005) Phosphorus nutrition-mediated effects of arbuscular mycorrhiza on leaf morphology and carbon allocation in perennial ryegrass. New Phytol 168:435–444

    PubMed  Google Scholar 

  • Grimoldi AA, Kavanová M, Lattanzi FA, Schäufele R, Schnyder H (2006) Arbuscular mycorrhizal colonization on carbon economy in perennial ryegrass: quantification by 13CO2/12CO2 steady-state labelling and gas exchange. New Phytol 172:544–553

    PubMed  Google Scholar 

  • Guerrieri R, Belmecheri S, Ollinger SV, Asbjornsen H, Jennings K, Xiao J, Stocker BD, Martin M, Hollinger DY, Bracho-Garrillo R, Clark K, Dore S, Kolb T, Munger JW, Novick K, Richardson AD (2019) Disentangling the role of photosynthesis and stomatal conductance on rising forest water-use efficiency. Proc Natl Acad Sci 116:16909–16914

    PubMed  PubMed Central  Google Scholar 

  • Hirl RT, Schnyder H, Ostler U, Schäufele R, Schleip I, Vetter SH, Auerswald K, Baca Cabrera JC, Wingate L, Barbour MM, Ogée J (2019) The 18O ecohydrology of a grassland ecosystem – predictions and observations. Hydrol Earth Syst Sci 23:2581–2600

    Google Scholar 

  • Hirl RT, Ogee J, Ostler U, Schäufele R, Baca Cabrera JC, Zhu J, Schleip I, Wingate L, Schnyder H (2021) Temperature-sensitive biochemical 18O-fractionation and humidity-dependent attenuation factor are needed to predict δ18O of cellulose from leaf water in a grassland ecosystem. New Phytol 229:3156–3171

    PubMed  Google Scholar 

  • Horst GL, Nelson CJ, Asay KH (1978) Relationship of leaf elongation to forage yield of tall fescue genotypes. Crop Sci 18:715–719

    Google Scholar 

  • Jacquez J (1996) Compartmental analysis in biology and medicine. Elsevier, Amsterdam

    Google Scholar 

  • Jones RJ, Ludlow RJ, Troughton JH, Blunt CG (1981) Changes in the natural carbon isotope ratios of the hair from steers fed diets of C4, C3 and C4 species in sequence. Search 12:85–87

    Google Scholar 

  • Kavanová M, Grimoldi AA, Lattanzi FA, Schnyder H (2006a) Phosphorus nutrition and mycorrhiza effects on grass leaf growth. P status- and size-mediated effects on growth zone kinematics. Plant Cell Environ 29:511–520

    PubMed  Google Scholar 

  • Kavanová M, Lattanzi FA, Grimoldi AA, Schnyder H (2006b) Phosphorus deficiency decreases cell division and elongation in grass leaves. Plant Physiol 141:766–775

    PubMed  PubMed Central  Google Scholar 

  • Kavanová M, Lattanzi FA, Schnyder H (2008) Nitrogen deficiency inhibits leaf blade growth in Lolium perenne by increasing cell cycle duration and decreasing mitotic and post-mitotic growth rates. Plant Cell Environ 31:727–737

    PubMed  Google Scholar 

  • Keys AJ, Sampaio EVSB, Cornelius MJ, Bird IF (1977) Effect of temperature on photosynthesis and photorespiration of wheat leaves. J Exp Bot 28:525–533

    Google Scholar 

  • Keys AJ, Bird IF, Cornelius MJ, Lea PJ, Wallsgrove RM, Miflin BJ (1978) Photorespiratory nitrogen cycle. Nature 275:741–743

    Google Scholar 

  • Klumpp K, Schäufele R, Lötscher M, Lattanzi FA, Feneis W, Schnyder H (2005) C-isotope composition of CO2 respired by shoots and roots: fractionation during dark respiration? Plant Cell Environ 28:241–250

    Google Scholar 

  • Köhler IH, Paul RP, Auerswald K, Schnyder H (2010) Intrinsic water-use efficiency of temperate seminatural grassland has increased since 1857: an analysis of carbon isotope discrimination of herbage from the Park Grass experiment. Glob Chang Biol 16:1531–1541

    Google Scholar 

  • Köhler IH, Macdonald A, Schnyder H (2012) Nutrient supply enhanced the increase in intrinsic water-use efficiency of a temperate semi-natural grassland in the last century. Glob Chang Biol 18:3367–3376

    Google Scholar 

  • Köhler IH, Macdonald AJ, Schnyder H (2016) Last-century increases in intrinsic water-use efficiency of grassland communities have occurred over a wide range of vegetation composition, nutrient inputs, and soil pH. Plant Physiol 170:881–890

    PubMed  Google Scholar 

  • Körner C, Farquhar GD, Wong SC (1991) Carbon isotope discrimination by plants follows latitudinal and altitudinal trends. Oecologia 88:30–40

    PubMed  Google Scholar 

  • Kühbauch W, Schnyder H (1989). Fructan (Special Issue)) J Plant Physiol 134:121–260

    Google Scholar 

  • Kühbauch W, Thome U (1989) Nonstructural carbohydrates of wheat stems as influenced by source-sink manipulations. J Plant Physiol 134:243–250

    Google Scholar 

  • Lattanzi FA, Schnyder H, Thornton B (2004) Defoliation effects on carbon and nitrogen substrate import and tissue-bound efflux in leaf growth zones of grasses. Plant Cell Environ 27:347–356

    Google Scholar 

  • Lattanzi FA, Schnyder H, Thornton B (2005) The sources of carbon and nitrogen supplying leaf growth. Assessment of the role of stores with compartmental models. Plant Physiol 137:383–395

    PubMed  PubMed Central  Google Scholar 

  • Lattanzi FA, Ostler U, Wild M, Morvan-Bertrand A, Decau ML, Lehmeier CA, Meuriot F, Prud’homme M-P, Schäufele R, Schnyder H (2012a) Fluxes in central carbohydrate metabolism of source leaves in a fructan-storing C3 grass: rapid turnover and futile cycling of sucrose in continuous light under contrasted nitrogen nutrition status. J Exp Bot 63:2363–2375

    PubMed  Google Scholar 

  • Lattanzi FA, Berone GD, Feneis W, Schnyder H (2012b) 13C-labeling shows the effect of hierarchy on the carbon gain of individuals and functional groups in dense field stands. Ecology 93:169–179

    PubMed  Google Scholar 

  • Lehmann MM, Gamarra B, Kahmen A, Siegwolf RT, Saurer M (2017) Oxygen isotope fractionations across individual leaf carbohydrates in grass and tree species. Plant Cell Environ 40:1658–1670

    PubMed  Google Scholar 

  • Lehmeier CA, Schäufele R, Schnyder H (2005) Allocation of reserve-derived and currently assimilated carbon and nitrogen in seedlings of Helianthus annuus under subambient and elevated CO2 growth conditions. New Phytol 168:613–621

    PubMed  Google Scholar 

  • Lehmeier CA, Lattanzi FA, Schäufele R, Wild M, Schnyder H (2008) Root and shoot respiration of perennial ryegrass are supplied by the same substrate pools: assessment by dynamic 13C labeling and compartmental analysis of tracer kinetics. Plant Physiol 148:1148–1158

    PubMed  PubMed Central  Google Scholar 

  • Lehmeier CA, Lattanzi FA, Gamnitzer U, Schäufele R, Schnyder H (2010a) Day-length effects on carbon stores for respiration of perennial ryegrass. New Phytol 188:719–725

    PubMed  Google Scholar 

  • Lehmeier CA, Lattanzi FA, Schäufele R, Schnyder H (2010b) Nitrogen deficiency increases the residence time of respiratory carbon in the respiratory substrate supply system of perennial ryegrass. Plant Cell Environ 33:76–87

    PubMed  Google Scholar 

  • Lehmeier CA, Wild M, Schnyder H (2013) Nitrogen stress affects the turnover and size of nitrogen pools supplying leaf growth in a grass. Plant Physiol 162:2095–2105

    PubMed  PubMed Central  Google Scholar 

  • Liu HT, Gong XY, Schäufele R, Yang F, Hirl RT, Schmidt A, Schnyder H (2016) Nitrogen fertilization and δ18O of CO2 have no effect on 18O-enrichment of leaf water and cellulose in Cleistogenes squarrosa (C4) – is VPD the sole control? Plant Cell Environ 39:2701–2712

    PubMed  Google Scholar 

  • Liu HT, Schäufele R, Gong XY, Schnyder H (2017a) The δ18O and δ2H of water in the leaf growth-and-differentiation zone of grasses is close to source water in both humid and dry atmospheres. New Phytol 214:1423–1431

    PubMed  Google Scholar 

  • Liu HT, Yang F, Gong XY, Schäufele R, Schnyder H (2017b) An oxygen isotope chronometer for cellulose deposition: the successive leaves formed by tillers of a C4 perennial grass. Plant Cell Environ 40:2121–2132

    PubMed  Google Scholar 

  • Lorimer GH, Badger MR, Andrews JT (1977) D-Ribulose-1.5-bisphosphate carboxylase-oxygenase improved methods for the activation and assay of catalytic activities. Anal Biochem 78:66–75

    PubMed  Google Scholar 

  • Lötscher M, Klumpp K, Schnyder H (2004) Growth and maintenance respiration for individual plants in hierarchically structured canopies of Medicago sativa and Helianthus annuus: the contribution of current and old assimilates. New Phytol 164:305–316

    PubMed  Google Scholar 

  • Ludwig LJ, Canvin DT (1971) An open gas exchange system for the simultaneous measurement of the CO2 and 14CO2 fluxes from leaves. Can J Bot 49:1299–1313

    Google Scholar 

  • Ma WT, Tcherkez G, Wang XM, Schäufele R, Schnyder H, Yang Y, Gong XY (2021) Accounting for mesophyll conductance substantially improves 13C-based estimates of intrinsic water-use efficiency. New Phytol 229:1326–1338

    PubMed  Google Scholar 

  • Mächler F, Nösberger J (1977) Effect of light intensity and temperature on apparent photosynthesis of altitudinal ecotypes of Trifolium repens L. Oecologia 31:73–78

    PubMed  Google Scholar 

  • Mächler F, Nösberger (1980) Regulation of ribulose bisphosphate carboxylase activity in intact wheat leaves by light, CO2, and temperature. J Exp Bot 31:1485–1491

    Google Scholar 

  • Mächler F, Nösberger J, Erismann KH (1977) Photosynthetic 14CO2 fixation products in altitudinal ecotypes of Trifolium repens L. with different temperature requirements. Oecologia 31:79–84

    PubMed  Google Scholar 

  • Mächler F, Keys AJ, Cornelius MJ (1980) Activation of ribulose bisphosphate carboxylase purified from wheat leaves. J Exp Bot 31:7–14

    Google Scholar 

  • Männel TT, Auerswald K, Schnyder H (2007) Altitudinal gradients of grassland carbon and nitrogen isotope composition are recorded in the hair of grazers. Glob Ecol Biogeogr 16:583–592

    Google Scholar 

  • Mathias JM, Thomas RB (2021) Global tree intrinsic water use efficiency is enhanced by increased atmospheric CO2 and modulated by climate and plant functional types. Proc Natl Acad Sci 118:e2014286118

    PubMed  PubMed Central  Google Scholar 

  • Matyssek R, Schnyder H, Osswald W, Ernst D, Much JC, Pretzsch H (2012) Growth and defence in plants. Resource allocation at multiple scales. In: Caldwell MM, Heldmaier G, Jackson RB, Lange OL, Mooney HA, Schulze E-D, Sommer U (eds) Ecological studies 220. Springer, Berlin

    Google Scholar 

  • Minson DJ, Ludlow MM, Troughton JH (1975) Differences in natural carbon isotope ratios of milk and hair from cattle grazing tropical and temperate pastures. Nature 256:602

    PubMed  Google Scholar 

  • Moorby J, Jarman PD (1975) The use of compartmental analysis in the study of the movement of carbon through leaves. Planta 122:155–168

    PubMed  Google Scholar 

  • Müller I (2006) Diurnal cycles of oxygen isotope signatures of leaf water, soil water, dew and humidity in a central European grassland ecosystem. Diploma thesis, Technical University of Munich

    Google Scholar 

  • Nelson CJ, Smith D (1986) Fructans: their nature and occurrence. Curr Topics Plant Biochem Physiol 5:1–16

    Google Scholar 

  • Nelson CJ, Spollen WG (1987) Fructans. Physiol Plant 71:512–516

    Google Scholar 

  • Ogée J, Brunet Y, Loustau D, Berbigier P, Delzon S (2003) MuSICA, a CO2, water and energy multilayer, multi-leaf pine forest model: evaluation from hourly to yearly time scales and sensitivity analysis. Glob Chang Biol 9:697–717

    Google Scholar 

  • Ostler U, Schleip I, Lattanzi FA, Schnyder H (2016) Carbon dynamics in aboveground biomass of co-dominant plant species in a temperate grassland ecosystem: same or different? New Phytol 210:471–484

    PubMed  Google Scholar 

  • Pierre J-I (1869) Recherches experimentales sur le development du blé et sur la repartition, dans ses differentes partes, des elements qui le constituent a diverses époques de son development. Mémoires de la Société Linnéenne de Normandie, pp 1–220

    Google Scholar 

  • Pollock CJ, Cairns AJ (1991) Fructan metabolism in grasses and cereals. Annu Rev Plant Physiol Plant Mol Biol 42:77–101

    Google Scholar 

  • Portis AR, Li C, Wang D, Salvucci ME (2008) Regulation of Rubisco activase and its interaction with Rubisco. J Exp Bot 59:1597–1604

    PubMed  Google Scholar 

  • Preston T, Owens NJP (1985) Preliminary 13C measurements using a gas chromatograph interfaced to an isotope ratio mass spectrometer. Biomed Mass Spectrom 12:510–513

    Google Scholar 

  • Prosser J, Farrar JF (1981) A compartmental model of carbon allocation in the vegetative barley plant. Plant Cell Environ 4:303–307

    Google Scholar 

  • Rademacher IF, Nelson CJ (2001) Nitrogen effects on leaf anatomy within the intercalary meristems of tall fescue leaf blades. Ann Bot 88:893–903

    Google Scholar 

  • Ratcliffe RG, Shachar-Hill Y (2006) Measuring multiple fluxes through plant metabolic networks. Plant J 45:490–511

    PubMed  Google Scholar 

  • Rose V (1804) Über eine eigenthümliche vegetabilische Substanz. Neues Allg J Chem 3:217–219

    Google Scholar 

  • Rossmann A (2001) Determination of stable isotope ratios in food analysis. Food Rev Intl 17:347–381

    Google Scholar 

  • Sala OE, Chapin FS III, Armesto JJ, Berlow E, Bloomfield J, Dirzo R, Huber-Sanwald E, Huenneke LF, Jackson RB, Kinzig A, Leemans R, Lodge DM, Mooney HA, Oesterheld M, LeRoy PN, Sykes MT, Walker BH, Walker M, Wall DH (2000) Global biodiversity scenarios for the year 2100. Science 287:1770–1774

    PubMed  Google Scholar 

  • Saurer M, Siegwolf RTW, Schweingruber FH (2004) Carbon isotope discrimination indicates improving water-use efficiency of trees in northern Eurasia over the last 100 years. Glob Chang Biol 19:2109–2120

    Google Scholar 

  • Schäufele R, Schnyder H (2000) Cell growth analysis during steady and non-steady growth in leaves of perennial ryegrass (Lolium perenne L.) subject to defoliation. Plant Cell Environ 23:185–194

    Google Scholar 

  • Schäufele R, Schnyder H (2001) Carbon and nitrogen deposition in expanding tissue elements of perennial ryegrass (Lolium perenne L.) leaves during non-steady growth after defoliation. Plant Cell Environ 24:407–417

    Google Scholar 

  • Schäufele R, Santrucek J, Schnyder H (2011) Dynamic changes of canopy-scale mesophyll conductance to CO2 diffusion of sunflower as affected by CO2 concentration and abscisic acid. Plant Cell Environ 34:127–136

    PubMed  Google Scholar 

  • Scheidegger Y, Saurer M, Bahn M, Siegwolf R (2000) Linking stable oxygen and carbon isotopes with stomatal conductance and photosynthetic capacity: a conceptual model. Oecologia 125:350–357

    PubMed  Google Scholar 

  • Schleip I, Lattanzi FA, Schnyder H (2013) Common leaf life span of co-dominant species in a continuously grazed temperate pasture. Basic Appl Ecol 14:54–63

    Google Scholar 

  • Schnyder H (1984) Der Einfluss des Aktivierungszustandes und der katalytischen Eigenschaften der Ribulose-1.5-bisphosphat Carboxylase/Oxygenase auf die Photosynthese intakter Blätter von Weissklee (Trifolium repens L.). Dissertation, Eidgenössische Technische Hochschule Zürich

    Google Scholar 

  • Schnyder H (1990) Untersuchung des Kohlenstoffhaushaltes und Reservekohlenhydratstoffwechsels in Pflanzen über Langzeit 13C/12C-Markierung mit natürlichen CO2-Quellen: Theorie, Methoden und Anwendung. Habilitationsschrift, Universität Bonn

    Google Scholar 

  • Schnyder H (1992) Long-term steady-state labelling of wheat plants by use of natural 13CO2/12CO2 mixtures in an open, rapidly turned-over system. Planta 187:128–135

    PubMed  Google Scholar 

  • Schnyder H (1993) The role of carbohydrate storage and redistribution in the source-sink relations of wheat and barley during grain filling – a review. New Phytol 123:233–245

    Google Scholar 

  • Schnyder H, Auerswald K (2008) Isotopes as natural recorders of grassland ecosystem functioning and change. In: Conference OColl (ed) multifunctional grasslands in a changing world, vol 1. Guangdong People’s Publishing House, Guangzhou, pp 46–51

    Google Scholar 

  • Schnyder H, Baum U (1992) Growth of the grain of wheat (Triticum aestivum L.). The relationship between water content and dry matter accumulation. Eur J Agron 1:51–57

    Google Scholar 

  • Schnyder H, de Visser R (1999) Fluxes of reserve-derived and currently assimilated carbon and nitrogen in perennial ryegrass recovering from defoliation. The regrowing tiller and its component functionally distinct zones. Plant Physiol 119:1423–1435

    PubMed  PubMed Central  Google Scholar 

  • Schnyder H, Lattanzi FA (2005) Partitioning respiration of C3-C4 mixed communities using the natural abundance 13C approach – testing assumptions in a controlled environment. Plant Biol 7:592–600

    PubMed  Google Scholar 

  • Schnyder H, Nelson CJ (1987) Growth rates and carbohydrate fluxes within the elongation zone of tall fescue leaf blades. Plant Physiol 85:548–553

    PubMed  PubMed Central  Google Scholar 

  • Schnyder H, Nelson CJ (1988) Diurnal growth of tall fescue leaf blades. I. Spatial distribution of growth, deposition of water and assimilate import in the elongation zone. Plant Physiol 86:1070–1076

    PubMed  PubMed Central  Google Scholar 

  • Schnyder H, Nelson CJ (1989) Growth rates and assimilate partitioning in the elongation zone of tall fescue leaf blades at high and low irradiance. Plant Physiol 90:1201–1206

    PubMed  PubMed Central  Google Scholar 

  • Schnyder H, Weiss J (1993) Growth of the grain of wheat (Triticum aestivum L.). The significance and timing of greening. Eur J Agron 2:93–98

    Google Scholar 

  • Schnyder H, Mächler F, Nösberger J (1984) Influence of temperature and O2 concentration on photosynthesis and light activation of Ribulosebisphosphate carboxylase oxygenase in intact leaves of white clover (Trifolium repens L.). J Exp Bot 25:147–156

    Google Scholar 

  • Schnyder H, Mächler F, Nösberger J (1986) Regeneration of ribulose 1,5-bisphosphate and ribulose 1,5-bisphosphate carboxylase/oxygenase activity associate with lack of oxygen inhibition of photosynthesis at low temperature. J Exp Bot 37:1170–1179

    Google Scholar 

  • Schnyder H, Nelson CJ, Coutts JH (1987) Assessment of spatial distribution of growth in the elongation zone of grass leaf blades. Plant Physiol 85:290–293

    PubMed  PubMed Central  Google Scholar 

  • Schnyder H, Nelson CJ, Spollen WG (1988) Diurnal growth of tall fescue leaf blades. I. Dry matter partitioning and carbohydrate metabolism in the elongation zone and adjacent expanded tissue. Plant Physiol 86:1077–1083

    PubMed  PubMed Central  Google Scholar 

  • Schnyder H, Seo S, Rademacher IF, Kühbauch W (1990) Spatial distribution of growth rates and of epidermal cell lengths in the elongation zone during leaf development in Lolium perenne L. Planta 181:423–431

    PubMed  Google Scholar 

  • Schnyder H, Gillenberg C, Hinz J (1993) Fructan contents and dry matter deposition in different tissues of the wheat grain during development. Plant Cell Environ 16:179–187

    Google Scholar 

  • Schnyder H, Schäufele R, de Visser R, Nelson CJ (2000) An integrated view of C and N uses in leaf growth zones of defoliated grasses. In G Lemaire, A de Moraes, C Nabinger, PC de F Carvalho Grassland ecophysiology and grazing ecology, CAB International, Wallingford

    Google Scholar 

  • Schnyder H, Schäufele R, Lötscher M, Gebbing T (2003) Disentangling CO2 fluxes: direct measurements of mesocosm-scale natural abundance 13CO2/12CO2 gas exchange, 13C-discrimination, and labelling of CO2 exchange flux components in controlled environments. Plant Cell Environ 26:1863–1874

    Google Scholar 

  • Schnyder H, Schäufele R, Wenzel R (2004) Mobile, outdoor continuous-flow isotope-ratio mass spectrometer system for automated high-frequency 13C- and 18O-CO2 analysis for keeling plot applications. Rapid Commun Mass Spectrom 18:3068–3074

    PubMed  Google Scholar 

  • Schnyder H, Ostler U, Lehmeier CA, Wild M, Morvan-Bertrand A, Schäufele R, Lattanzi FA (2012) Tracing carbon fluxes: resolving complexity using isotopes. In: Matyssek R, Schnyder H, Munch JC, Osswald W, Pretzsch H (eds) Growth and defence in plants: resource allocation at multiple scales, Ecological studies, vol 220. Springer, Berlin, pp 157–173

    Google Scholar 

  • Schnyder H, Idota S, Kajiya Y, Auerswald K, Schäufele R, Wenzel R, Song R, Li G, Kimura R, Tasumi M, Nishiwaki A, Ishii Y, Hirata M, Hasegawa N (2014) Isotope ecology of Yak in Tibet-Transhimalaya alpine rangelands. Jap J Grassl Sci 60:27

    Google Scholar 

  • Schnyder H, Lehmeier CA, Ostler U (2017) Respiratory turn-over and metabolic compartments: from the design of tracer experiments to the characterization of respiratory substrate-supply systems. In: Tcherkez G, Ghashghaie J (eds) Plant respiration: metabolic fluxes and carbon balance advances in photosynthesis and respiration. Springer Nature, Cham

    Google Scholar 

  • Schnyder H, Auerswald K, Geist J, Heissenhuber A (2019) Farmers need independent and holistic advice. Nature 571:326

    PubMed  Google Scholar 

  • Schwertl M, Auerswald K, Schnyder H (2003) Reconstruction of the isotopic history of animal diets by hair segmental analysis. Rapid Commun Mass Spectrom 17:1312–1318

    PubMed  Google Scholar 

  • Schwertl M, Auerswald K, Schnyder H (2005) Carbon and nitrogen stable isotope composition of cattle hair: ecological fingerprints of production systems? Agric Ecosyst Environ 109:153–165

    Google Scholar 

  • Seibt U, Rajabi A, Griffiths H, Berry JA (2008) Carbon isotopes and water use efficiency: sense and sensitivity. Oecologia 155:441–454

    PubMed  Google Scholar 

  • Shimshi D (1969) A rapid field method for measuring photosynthesis with labelled carbon dioxide. J Exp Bot 20:381–401

    Google Scholar 

  • Silk WK (1984) Quantitative descriptions of development. Annu Rev Plant Physiol 35:479–518

    Google Scholar 

  • Spollen WG, Nelson CJ (1986) Water soluble carbohydrate composition of leaf elongation zones and mature leaf blades of three grass species. Curr Top Plant Biochem Physiol 5:201

    Google Scholar 

  • Sternberg L, Ellsworth PFV (2011) Divergent biochemical fractionation, not convergent temperature, explains cellulose oxygen isotope enrichment across latitudes. PloS One 6:e28040

    PubMed  PubMed Central  Google Scholar 

  • Sternberg L, DeNiro M, Savidge R (1986) Oxygen isotope exchange between metabolites and water during biochemical reactions leading to cellulose synthesis. Plant Physiol 82:423–427

    PubMed  PubMed Central  Google Scholar 

  • Storkey J, Macdonald AJ, Poulton PR, Scott T, Köhler IH, Schnyder H, Goulding KWT, Crawley MJ (2015) Grassland biodiversity bounces back from long-term nitrogen addition. Nature 528:401–404

    PubMed  Google Scholar 

  • Strömberg CAE (2011) Evolution of grasses and grassland ecosystems. Annu Rev Earth Planet Sci 39:517–544

    Google Scholar 

  • Sun L, Auerswald K, Schäufele R, Schnyder H (2010) Oxygen and hydrogen isotope composotion of silage water. J Agric Food Chem 62:4493–4501

    Google Scholar 

  • Sun L, Auerswald K, Wenzel R, Schnyder H (2014) Drinking water intake of grazing steers: the role of environmental factors controlling canopy wetness. J Anim Sci 92:282–291

    PubMed  Google Scholar 

  • Tcherkez G, Schäufele R, Nogués S, Piel C, Boom A, Lanigan G, Barbaroux C, Mata C, Elhani S, Hemming D, Maguas C, Yakir D, Badeck FW, Griffiths H, Schnyder H, Ghashghaie J (2010) On the 13C/12C isotopic signal of day and night respiration at the mesocosm level. Plant Cell Environ 33:900–913

    PubMed  Google Scholar 

  • Thome U, Kühbauch W (1985) Changes in the carbohydrate pattern in the cell content of wheat stems during grain-filling. J Agron Crop Sci 155:253–260

    Google Scholar 

  • Vassey TL, Schnyder H, Spollen WG, Nelson CJ (1985) Cellular characterization and fructan profiles in expanding tall fescue leaves. Curr Top Plant Biochem Physiol 4:227

    Google Scholar 

  • Versluys M, Kirtel O, Öner ET, van den Ende W (2017) The fructan syndrome: evolutionary aspects and common themes among plants and microbes. Plant Cell Environ 41:16–38

    PubMed  Google Scholar 

  • Volenec JJ, Nelson CJ (1981) Cell dynamics in leaf meristems of contrasting tall fescue genotypes. Crop Sci 21:381–385

    Google Scholar 

  • Volenec JJ, Nelson CJ (1982) Diurnal leaf elongation of contrasting tall fescue genotypes. Crop Sci 22:531–535

    Google Scholar 

  • Volenec JJ, Nelson CJ (1984a) Carbohydrate metabolism in leaf meristems of tall fescue. Relationship to genetically altered leaf elongation rates. Plant Physiol 74:590–594

    PubMed  PubMed Central  Google Scholar 

  • Volenec JJ, Nelson CJ (1984b) Carbohydrate metabolism in leaf meristems of tall fescue. Relationship to leaf elongation rates modified by nitrogen fertilization. Plant Physiol 74:595–600

    PubMed  PubMed Central  Google Scholar 

  • Wagner W, Keller F, Wiemken A (1983) Fructan metabolism in cereals: induction in leaves and compartmentation in protoplasts and vacuoles. J Plant Physiol 112:359–372

    Google Scholar 

  • Wingate L, Ogée J, Burlett R, Bosc A, Devaux M, Grace J, Loustau D, Gessler A (2010) Photosynthetic carbon isotope discrimination and its relationship to the carbon isotope signals of stem soil and ecosystem respiration. New Phytol 188(2):576–589. 10.1111/nph.2010.188.issue-2. https://doi.org/10.1111/j.1469-8137.2010.03384.x

    Article  PubMed  Google Scholar 

  • Wittmer MHOM, Auerswald K, Tungalag R, Bai YF, Schäufele R, Schnyder (2008) Carbon isotope discrimination of C3 vegetation in central Asian grassland as related to long-term and short-term precipitation patterns. Biogeosciences 5:913–924

    Google Scholar 

  • Wittmer MHOM, Auerswald K, Schönbach P, Schäufele R, Müller K, Yang H, Bai YF, Susenbeth A, Taube F, Schnyder H (2010a) Do grazer hair an faeces reflect the carbon isotope composition of semi-arid C3/C4 grassland? Basic Appl Ecol 11:83–92

    Google Scholar 

  • Wittmer MHOM, Auerswald K, Bai YF, Schäufele R, Schnyder H (2010b) Changes in the abundance of C3/C4 species of Inner Mongolia grassland: evidence from isotopic composition of soil and vegetation. Glob Chang Biol 16:605–616

    Google Scholar 

  • Yang F, Gong XY, Liu HT, Schäufele R, Schnyder H (2016a) Effects of nitrogen and vapour pressure deficit on phytomer growth and development in a C4 grass. AoB Plants 8:plw075. https://doi.org/10.1093/aobpla/plw075

    Article  PubMed  PubMed Central  Google Scholar 

  • Yang Z, Liu J, Tischer SV, Christmann A, Windisch W, Schnyder H, Grill E (2016b) Leveraging abscisic acid receptors for efficient water use in Arabidopsis. Proc Natl Acad Sci U S A 113:6791–6796

    PubMed  PubMed Central  Google Scholar 

  • Yang F, Schäufele R, Liu HT, Ostler U, Schnyder H, Gong XY (2020) Gross and net nitrogen export from leaves of a vegetative C4 grass. J Plant Physiol 244:153093

    PubMed  Google Scholar 

  • Zanetti S, Hartwig UA, Van Kessel C, Lüscher A, Hebeisen T, Frehner M, Fischer BU, Hendrey GR, Blum H, Nösberger J (1997) Does nitrogen nutrition restrict the CO2 response of fertile grassland lacking legumes? Oecologia 112:17–25

    PubMed  Google Scholar 

  • Zobitz JM, Keener JP, Schnyder H, Bowling DR (2006) Sensitivity analysis and quantification of uncertainty for isotopic mixing relationships in carbon cycle research. Agric Forest Meteorol 136:56–75

    Google Scholar 

Download references

Acknowledgment

I thank Ulrich Lüttge and Hans Pretzsch for the invitation, which gave me the opportunity to write this piece.

Author information

Authors and Affiliations

  1. Technische Universität München, Munich, Germany

    Hans Schnyder

Authors
  1. Hans Schnyder
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Hans Schnyder .

Editor information

Editors and Affiliations

  1. Department of Biology, Technical University of Darmstadt, Darmstadt, Germany

    Ulrich Lüttge

  2. Department of Molecular Biology and Biochemistry, University of Málaga, Málaga, Spain

    Francisco M. Cánovas

  3. Pollen Biotechnology of Crop Plants Group, Centro de Investigaciones Biologicas “Margarita Salas” (CIB) CSIC, Madrid, Madrid, Spain

    María-Carmen Risueño

  4. Plant Ecology, University of Göttingen, Göttingen, Germany

    Christoph Leuschner

  5. Chair for Forest Growth and Yield Science, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Bayern, Germany

    Hans Pretzsch

Rights and permissions

Reprints and permissions

Copyright information

© 2023 The Author(s), under exclusive license to Springer Nature Switzerland AG

About this chapter

Check for updates. Verify currency and authenticity via CrossMark

Cite this chapter

Schnyder, H. (2023). Explorations into the Physiology and Ecology of Grassland Plants and Ecosystems: One Agronomist’s Academic Journey. In: Lüttge, U., Cánovas, F.M., Risueño, MC., Leuschner, C., Pretzsch, H. (eds) Progress in Botany Vol. 84. Progress in Botany, vol 84. Springer, Cham. https://doi.org/10.1007/124_2023_72

Download citation

Publish with us

Policies and ethics

Search

Navigation