Barley (Hordeum vulgare) accumulates phenolic compounds (PhCs), which play a key role in plant defense against environmental stressors as antioxidants or UV screening compounds. The influence of light and atmospheric CO2 concentration ([CO2]) on the accumulation and localization of PhCs in barley leaves was examined for two varieties with different tolerances to oxidative stress. PhC localization was visualized in vivo using fluorescence microscopy. Close relationships were found between fluorescence-determined localization of PhCs in barley leaves and PhC content estimated using liquid chromatography coupled with mass spectroscopy detection. Light intensity had the strongest effect on the accumulation of PhCs, but the total PhC content was similar at elevated [CO2], minimizing the differences between high and low light. PhCs localized preferentially near the surfaces of leaves, but under low light, an increasing allocation of PhCs in deeper mesophyll layers was observed. The PhC profile was significantly different between barley varieties. The relatively tolerant variety accumulated significantly more hydroxycinnamic acids, indicating that these PhCs may play a more prominent role in oxidative stress prevention. Our research presents novel evidence that [CO2] modulates the accumulation of PhCs in barley leaves. Mesophyll cells, rather than epidermal cells, were most responsive to environmental stimuli in terms of PhC accumulation.

Department of Experimental Plant Biology Faculty of Science Charles University Viničná 5 12844 Praha Czech Republic

Department of Physics Faculty of Science University of Ostrava Dvořákova 7 70103 Ostrava Czech Republic

Global Change Research Institute Czech Academy of Sciences Bělidla 4a 60300 Brno Czech Republic

Zobrazit více v PubMed

Zohary D., Hopf M. Domestication of Plants in the Old World. Oxford University Press; Oxford, UK: 2000.

FAOSTAT . Crops/Regions/World List/Production Quantity for Barley. UN Food and Agriculture Organization Corporate Statistical Database; Rome, Italy: 2019.

Kamiyama M., Shibamoto T. Flavonoids with potent antioxidant activity found in young green barley leaves. J. Agric. Food Chem. 2021;60:6260–6267. doi: 10.1021/jf301700j. PubMed DOI

Baik B.K., Ullrich S.E. Barley for food: Characteristics, improvement, and renewed interest. J. Cereal Sci. 2008;48:233–242. doi: 10.1016/j.jcs.2008.02.002. DOI

Kruse J. Estimating Demand for Agricultural Commodities to 2050. Global Harvest Initiative; Washington, DC, USA: 2011. Report No. 3-16-10.

Cammarano D., Ceccarelli S., Grando S., Romagosa I., Benbelkacem A., Akar T., Al-Yassin A., Pecchioni N., Francia E., Ronga D. The impact of climate change on barley yield in the Mediterranean basin. Eur. J. Agron. 2019;106:1–11. doi: 10.1016/j.eja.2019.03.002. DOI

Xie W., Xiong W., Pan J., Ali T., Cui Q., Guan D., Meng J., Mueller N.D., Lin E., Davis S.J. Decreases in global beer supply due to extreme drought and heat. Nat. Plants. 2018;4:964–973. doi: 10.1038/s41477-018-0263-1. PubMed DOI

Jansen M.A., Hectors K., O′Brien N.M., Guisez Y., Potters G. Plant stress and human health: Do human consumers benefit from UV-B acclimated crops? Plant Sci. 2008;175:449–485. doi: 10.1016/j.plantsci.2008.04.010. DOI

De Gara L., Locato V., Dipierro S., de Pinto M.C. Redox homeostasis in plants. The challenge of living with endogenous oxygen production. Respir. Physiol. Neurobiol. 2010;173:S13–S19. doi: 10.1016/j.resp.2010.02.007. PubMed DOI

Foyer C., Noctor G. Redox homeostasis and antioxidant signaling: A metabolic interface between stress perception and physiological responses. Plant Cell. 2005;17:1866–1875. doi: 10.1105/tpc.105.033589. PubMed DOI PMC

Foyer C.H., Lelandais M., Kunert K.J. Photooxidative stress in plants. Physiol. Plant. 1994;92:696–717. doi: 10.1111/j.1399-3054.1994.tb03042.x. DOI

Klem K., Gargallo-Garriga A., Rattanapichai W., Oravec M., Holub P., Veselá B., Sardans J., Peñuelas J., Urban O. Distinct morphological, physiological, and biochemical responses to light quality in barley leaves and roots. Front. Plant Sci. 2019;10:1026. doi: 10.3389/fpls.2019.01026. PubMed DOI PMC

Fayez K.A., Bazaid S.A. Improving drought and salinity tolerance in barley by application of salicylic acid and potassium nitrate. J. Saudi Soc. Agric. Sci. 2014;13:45–55. doi: 10.1016/j.jssas.2013.01.001. DOI

Corcuera L.J. Biochemical basis for the resistance of barley to aphids. Phytochemistry. 1993;33:741–747. doi: 10.1016/0031-9422(93)85267-U. DOI

Pfanz H., Oppmann B., Wolf P., Lomsky B. Detoxification of air pollutants in the presence of apoplastic phenols. Ishs Acta Hortic. 1994;381:360–366. doi: 10.17660/ActaHortic.1994.381.44. DOI

Michalak A. Phenolic compounds and their antioxidant activity in plants growing under heavy metal stress. Pol. J. Environ. Stud. 2006;15:523–530.

Caldwell M.M., Robberecht R., Flint S.D. Internal filters: Prospects for UV-acclimation in higher plants. Physiol. Plant. 1983;58:445–450. doi: 10.1111/j.1399-3054.1983.tb04206.x. DOI

Rice-Evans C., Miller N., Paganga G. Antioxidant properties of phenolic compounds. Trends Plant Sci. 1997;2:152–159. doi: 10.1016/S1360-1385(97)01018-2. DOI

Chen J.W., Zhu Z.Q., Hu T.X., Zhu D.Y. Structure-activity relationship of natural flavonoids in hydroxyl radical-scavenging effects. Acta Pharmacol. Sin. 2002;23:667–672. PubMed

Cuvelier M.E., Richard H., Berset C. Comparison of the antioxidative activity of some acid-phenols: Structure-activity relationship. Biosci. Biotechnol. Biochem. 1992;56:324–325. doi: 10.1271/bbb.56.324. DOI

Agati G., Brunetti C., Di Ferdinando M., Ferrini F., Pollastri S., Tattini M. Functional roles of flavonoids in photoprotection: New evidence, lessons from the past. Plant Physiol. Biochem. 2013;72:35–45. doi: 10.1016/j.plaphy.2013.03.014. PubMed DOI

Hernández I., Alegre L., Van Breusegem F., Munné-Bosch S. How relevant are flavonoids as antioxidants in plants? Trends Plant Sci. 2009;14:125–132. doi: 10.1016/j.tplants.2008.12.003. PubMed DOI

Agati G., Azzarello E., Pollastri S., Tattini M. Flavonoids as antioxidants in plants: Location and functional significance. Plant Sci. 2012;196:67–76. doi: 10.1016/j.plantsci.2012.07.014. PubMed DOI

Akhtar T.A., Lees H.A., Lampi M.A., Enstone D., Brain R.A., Greenberg B.M. Photosynthetic redox imbalance influences flavonoid biosynthesis in Lemma gibba. Plant Cell Environ. 2010;33:1205–1219. PubMed

Hutzler P., Fischbach R., Heller W., Jungblut T.P., Reuber S., Schmitz R., Veit M., Weissenböck G., Schnitzler J.P. Tissue localization of phenolic compounds in plants by confocal laser scanning microscopy. J. Exp. Bot. 1998;49:953–965. doi: 10.1093/jxb/49.323.953. DOI

Burchard P., Bilger W., Weissenböck G. Contribution of hydroxycinnamates and flavonoids to epidermal shielding of UV-A and UV-B radiation in developing rye primary leaves as assessed by ultraviolet-induced chlorophyll fluorescence measurements. Plant Cell Environ. 2000;23:1373–1380. doi: 10.1046/j.1365-3040.2000.00633.x. DOI

Csepregi K., Neugart S., Schreiner M., Hideg É. Comparative evaluation of total antioxidant capacities of plant polyphenols. Molecules. 2016;21:208. doi: 10.3390/molecules21020208. PubMed DOI PMC

Agati G., Brunetti C., Fini A., Gori A., Guidi L., Landi M., Sebastiani F., Tattini M. Are flavonoids effective antioxidants in plants? Twenty years of our investigation. Antioxidants. 2020;9:1098. doi: 10.3390/antiox9111098. PubMed DOI PMC

Ibrahim M.H., Jaafar H.Z., Rahmat A., Rahman Z.A. The relationship between phenolics and flavonoids production with total non structural carbohydrate and photosynthetic rate in Labisia pumila Benth. under high CO2 and nitrogen fertilization. Molecules. 2011;16:162–174. doi: 10.3390/molecules16010162. PubMed DOI PMC

Wu Y.X., Tiedemann A.V. Light-dependent oxidative stress determines physiological leaf spot formation in barley. Phytopathology. 2004;94:584–592. doi: 10.1094/PHYTO.2004.94.6.584. PubMed DOI

Klem K., Ač A., Holub P., Kováč D., Špunda V., Robson T.M., Urban O. Interactive effects of PAR and UV radiation on the physiology, morphology and leaf optical properties of two barley varieties. Environ. Exp. Bot. 2012;75:52–64. doi: 10.1016/j.envexpbot.2011.08.008. DOI

Hartman I. Quality of malting barley grain in the Czech Republic, crop 2017. Kvasny Prumysl. 2018;64:64–69. doi: 10.18832/kp201834. DOI

Kofroň P., Skoblík R., Enge J., Sekora M. Testing of malting barley—Variety bojos. Kvasny Prumysl. 2006;52:179–184. doi: 10.18832/kp2006016. DOI

Agrární Komora České Republiky . Ústrědní Kontrolní a Zkušební Ústav Zemědělsý: Obilniny 2018. Národní odrůový úřad; Brno, Czech Republic: 2018.

Arenas-Corraliza M.G., Rolo V., López-Díaz M.L., Moreno G. Wheat and barley can increase grain yield in shade through acclimation of physiological and morphological traits in Mediterranean conditions. Sci. Rep. 2019;9:9547. doi: 10.1038/s41598-019-46027-9. PubMed DOI PMC

Philips M. The Chemistry of Lignin. Waverly Press; New York, NY, USA: 1934.

Gardner R. Vanillin-hydrochloric acid as a histochemical test for tannin. Stain Technol. 1975;50:315–317. doi: 10.3109/10520297509117081. PubMed DOI

Neu R. Chelates of diarylboric acids with aliphatic oxyalkylamines as reagents for the detection of oxyphenyl-benzo-γ-pyrones. Die Nat. 1957;44:181–182. doi: 10.1007/BF00599857. DOI

Valette C., Andary C., Geiger J.P., Sarah J.L., Nicole M. Histochemical and cytochemical investigations of phenols in roots of banana infected by the burrowing nematode Radopholus similis. Phytopathology. 1998;88:1141–1148. doi: 10.1094/PHYTO.1998.88.11.1141. PubMed DOI

Lichtenthaler H.K., Schweiger J. Cell wall bound ferulic acid, the major substance of the blue-green fluorescence emission of plants. J. Plant Physiol. 1998;152:272–282. doi: 10.1016/S0176-1617(98)80142-9. DOI

Albrechtová J., Kubínová Z., Soukup A., Janáček J. Image analysis: Basic procedures for description of plant structures. Methods Mol. Biol. 2014;1080:67–76. PubMed

Agati G., Cerovic Z.G., Pinelli P., Tattini M. Light-induced accumulation of ortho-dihydroxylated flavonoids as non-destructively monitored by chlorophyll fluorescence excitation techniques. Environ. Exp. Bot. 2011;73:3–9. doi: 10.1016/j.envexpbot.2010.10.002. DOI

Goulas Y., Cerovic Z.G., Cartelat A., Moya I. Dualex: A new instrument for field measurements of epidermal ultraviolet absorbance by chlorophyll fluorescence. Appl. Opt. 2004;43:4488–4496. doi: 10.1364/AO.43.004488. PubMed DOI

Smilauer P., Lepš J. Multivariate Analysis of Ecological Data Using Canoco 5. 2nd ed. Cambridge University Press; Cambridge, UK: 2014.

Day T.A., Martin G., Vogelmann T.C. Penetration of UV-B radiation in foliage: Evidence that the epidermis behaves as a non-uniform filter. Plant Cell Environ. 1993;16:735–741. doi: 10.1111/j.1365-3040.1993.tb00493.x. DOI

McClendon J.H., Fukshanksky L. On the interpretation of absorption spectra of leaves—II. The non-absorbed ray of the sieve effect and the mean optical pathlength in the remainder of the leaf. Photochem. Photobiol. 1990;51:211–216. doi: 10.1111/j.1751-1097.1990.tb01705.x. DOI

Kolb C.A., Pfündel E.E. Origins of non-linear and dissimilar relationships between epidermal UV absorbance and UV absorbance of extracted phenolics in leaves of grapevine and barley. Plant Cell Environ. 2005;25:580–590. doi: 10.1111/j.1365-3040.2005.01302.x. DOI

Li B., Neumann E.K., Ge J., Gao W., Yang H., Li P., Sweedler J.V. Interrogation of spatial metabolome of Ginkgo biloba with high-resolution matrix-assisted laser desorption/ionization and laser desorption/ionization mass spectrometry imaging. Plant Cell Environ. 2018;41:2693–2703. doi: 10.1111/pce.13395. PubMed DOI

Bogucka-Kocka A., Zidorn C., Kasprzycka M., Zyna Szymczak G., Szewczyk K. Phenolic acid content, antioxidant and cytotoxic activities of four Kalanchoë species. Saudi J. Biol. Sci. 2016;25:622–630. doi: 10.1016/j.sjbs.2016.01.037. PubMed DOI PMC

Hrazdina G., Wagner G. Metabolic pathways as enzyme complexes: Evidence for the synthesis of phenylpropanoids and flavonoids on membrane associated enzyme complexes. Arch. Biochem. Biophys. 1985;237:88–100. doi: 10.1016/0003-9861(85)90257-7. PubMed DOI

McNally D.J., Wurms K.V., Labbé C., Bélanger R.R. Synthesis of C-glycosyl flavonoid phytoalexins as a site-specific response to fungal penetration in cucumber. Physiol. Mol. Plant Pathol. 2003;63:293–303. doi: 10.1016/j.pmpp.2004.03.005. DOI

Schmitz-Hoerner R., Weissenböck G. Contribution of phenolic compounds to the UV-B screening capacity of developing barley primary leaves in relation to DNA damage and repair under elevated UV-B levels. Phytochemistry. 2003;64:243–255. doi: 10.1016/S0031-9422(03)00203-6. PubMed DOI

Mubarakshina M.M., Ivanov B.N., Naydov I.A., Hillier W., Badger M.R., Krieger-Liszkay A. Production and diffusion of chloroplastic H2O2 and its implication to signalling. J. Exp. Bot. 2010;61:3577–3587. doi: 10.1093/jxb/erq171. PubMed DOI

Zhao J., Dixon R.A. MATE transporters facilitate vacuolar uptake of epicatechin 3j-O-glucoside for proanthocyanidin biosynthesis in medicago truncatula and Arabidopsis. Plant Cell. 2009;21:2323–2340. doi: 10.1105/tpc.109.067819. PubMed DOI PMC

Tattini M., Galardi C., Pinelli P., Massai R., Remorini D., Agati G. Differential accumulation of flavonoids and hydroxycinnamates in leaves of Ligustrum vulgare under excess light and drought stress. New Phytol. 2004;163:547–561. doi: 10.1111/j.1469-8137.2004.01126.x. PubMed DOI

Liu L., Gitz D.C., McClure J.W. Effects of UV-B on flavonoids, ferulic add, growth and photosynthesis in barley primary leaves. Physiol. Plant. 1995;93:725–733. doi: 10.1111/j.1399-3054.1995.tb05123.x. DOI

Reuber S., Bornman J.F., Weissenböck G. Phenylpropanoid compounds in primary leaf tissues of rye (Secale cereale). Light response of their metabolism and the possible role in UV-B protection. Physiol. Plant. 1996;97:160–168. doi: 10.1111/j.1399-3054.1996.tb00492.x. DOI

Knogge W., Weissenböck G. Tissue-distribution of secondary phenolic biosynthesis in developing primary leaves of Avena sativa L. Planta. 1986;167:196–205. doi: 10.1007/BF00391415. PubMed DOI

Semerdjieva S.I., Sheffield E., Phoenix G.K., Gwynn-Jones D., Callaghan T.V., Johnson G.N. Contrasting strategies for UV-B screening in sub-Arctic dwarf shrubs. Plant Cell Environ. 2003;26:957–964. doi: 10.1046/j.1365-3040.2003.01029.x. PubMed DOI

Donaldson L. Autofluorescence in plants. Molecules. 2020;25:2393. doi: 10.3390/molecules25102393. PubMed DOI PMC

Harris P.J., Hartley R.D. Phenolic constituents of the cell walls of monocotyledons. Biochem. Syst. Ecol. 1980;8:153–160. doi: 10.1016/0305-1978(80)90008-3. DOI

Peltonen P.A., Vapaavuori E., Julkunen-Tiitto R. Accumulation of phenolic compounds in birch leaves is changed by elevated carbon dioxide and ozone. Glob. Chang. Biol. 2005;11:1305–1324. doi: 10.1111/j.1365-2486.2005.00979.x. DOI

Kowalczewski P.L., Radzikowska D., Ivanišová E., Szwengiel A., Kačániová M., Sawinska Z. Influence of abiotic stress factors on the antioxidant properties and polyphenols profile composition of green barley (Hordeum vulgare L.) Int. J. Mol. Sci. 2020;21:397. doi: 10.3390/ijms21020397. PubMed DOI PMC

Tattini M., Guidi L., Morassi-Bonzi L., Pinelli P., Remorini D., DeglÍnnocenti E., Giordano C., Massai R., Agati G. On the role of flavonoids in the integrated mechanisms of response of Ligustrum vulgare and Phillyrea latifolia to high solar radiation. New Phytol. 2005;167:457–470. doi: 10.1111/j.1469-8137.2005.01442.x. PubMed DOI

Grace S.G., Logan B.A. Energy dissipation and radical scavenging by the plant phenylpropanoid pathway. Philos. Trans. R. Soc. B. 2000;355:1499–1510. doi: 10.1098/rstb.2000.0710. PubMed DOI PMC

Delmas R.J., Ascencio J.M., Legrand M. Polar ice evidence that atmospheric CO2 20,000 yr BP was 50% of present. Nature. 1980;284:155–157. doi: 10.1038/284155a0. DOI

Ehleringer J.R., Cerling T.E. Atmospheric CO2 and the ratio of intercellular to ambient CO2 concentrations in plants. Tree Physiol. 1995;15:105–111. doi: 10.1093/treephys/15.2.105. PubMed DOI

Fatichi S., Leuzinger S., Körner C. Moving beyond photosynthesis: From carbon source to sink-driven vegetation modeling. New Phytol. 2014;201:1086–1095. doi: 10.1111/nph.12614. PubMed DOI

Palacio S., Hoch G., Sala A., Körner C., Millard P. Dies carbon storage limit tree growth? New Phytol. 2014;201:1096–1100. doi: 10.1111/nph.12602. PubMed DOI

Jaafar H.Z., Ibrahim M.H., Karimi E. Phenolics and flavonoids compounds, phenylanine ammonia lyase and antioxidant activity responses to elevated CO2 in Labisia pumila (Myrisinaceae) Molecules. 2012;17:6331–6347. doi: 10.3390/molecules17066331. PubMed DOI PMC

Lhotáková Z., Urban O., Dubánková M., Cvikrová M., Tomášková I., Kubínová L., Zvára K., Marek M.V., Albrechtová J. The impact of long-term CO2 enrichment on sun and shade needles of Norway spruce (Picea abies): Photosynthetic performance, needle anatomy and phenolics accumulation. Plant Sci. 2012;188–189:60–70. PubMed

Peñuelas J., Estiarte M., Kimball B.A., Idso S.B., Pinter P.J., Wall G.W., Garcia R.L., Hansaker D.J., LaMorte R.L., Hendrix D.L. Variety of responses of plant phenolic concentration to CO2 enrichment. J. Exp. Bot. 1996;47:1463–1467.

Poorter H., Niinemets Ü., Poorter L., Wright I.J., Villar R. Causes and consequences of variation in leaf mass per area (LMA): A meta-analysis. New Phytol. 2009;182:565–588. doi: 10.1111/j.1469-8137.2009.02830.x. PubMed DOI

Yi Z., Cui J., Fu Y., Liu H. Effect of different light intensity on physiology, antioxidant capacity and photosynthetic characteristics on wheat seedlings under high CO2 concentration in a closed artificial ecosystem. Photosynth. Res. 2020;144:23–34. doi: 10.1007/s11120-020-00726-x. PubMed DOI

Holub P., Nezval J., Štroch M., Špunda V., Urban O., Jansen M.A., Klem K. Induction of phenolic compounds by UV and PAR is modulated by leaf ontogeny and barley genotype. Plant Physiol. Biochem. 2019;134:81–93. doi: 10.1016/j.plaphy.2018.08.012. PubMed DOI

Klepacka J., Gujska E., Michalak J. Phenolic compounds as cultivar- and variety-distinguishing factors in some plant products. Plant Foods Hum. Nutr. 2011;66:64–69. doi: 10.1007/s11130-010-0205-1. PubMed DOI PMC

Walters D., Mitchella A., Hampson J., McPherson A. The induction of systemic resistance in barley to powdery mildew infection using salicylates and various phenolic acids. Ann. Appl. Biol. 1993;122:451–456. doi: 10.1111/j.1744-7348.1993.tb04048.x. DOI

Oliver G., editor. The Oxford Companion to Beer. Oxford University Press; Oxford, UK: 2011.

Bridging the Gap: From Photoperception to the Transcription Control of Genes Related to the Production of Phenolic Compounds

Leaf Functional Traits in Relation to Species Composition in an Arctic-Alpine Tundra Grassland

Regulation of Phenolic Compound Production by Light Varying in Spectral Quality and Total Irradiance

Barley Genotypes Vary in Stomatal Responsiveness to Light and CO2 Conditions