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Morris P, Carter EB, Hauck B, Lanot A, Theodorou MK, Allison G. Responses of Lotus corniculatus to environmental change 3: The sensitivity of phenolic accumulation to growth temperature and light intensity and effects on tissue digestibility. PLANTA 2021; 253:35. [PMID: 33459906 DOI: 10.1007/s00425-020-03524-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 12/02/2020] [Indexed: 06/12/2023]
Abstract
Growth temperature and light intensity are major drivers of phenolic accumulation in Lotus corniculatus resulting in major changes in carbon partitioning which significantly affects tissue digestibility and forage quality. The response of plant growth, phenolic accumulation and tissue digestibility to light and temperature was determined in clonal plants of three genotypes of Lotus corniculatus (birdsfoot trefoil) cv Leo, with low, intermediate or high levels of proanthocyanidins (condensed tannins). Plants were grown from 10 °C to 30 °C, or at light intensities from 20 to 500 µm m-2 s-1. Plants grown at 25 °C had the highest growth rate and highest digestibility, whereas the maximum tannin concentration was found in plants grown at 15 °C. Approximately linear increases in leaf flavonol glycoside levels were found with increasing growth temperature in the low tannin genotype. Tannin hydroxylation increased with increasing growth temperature but decreased with increasing light intensity. The major leaf flavonols were kaempferol glycosides of which kaempferol-3-glucoside and kaempferol-3,7-dirhamnoside were the major components. Increases in both tannin and total flavonol concentrations in leaves were linearly related to light intensity and were preceded by a specific increase in the transcript level of a non-legume type chalcone isomerase. Changes in growth temperature and light intensity, therefore, result in major changes in the partitioning of carbon into phenolics, which significantly affects tissue digestibility and nutritional quality with a high correlation between tannin concentration and leaf digestibility.
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Affiliation(s)
- Phillip Morris
- Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, Ceredigion, SY23 3EB, UK.
| | - Eunice B Carter
- Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, Ceredigion, SY23 3EB, UK
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Plas Gogerddan, Aberystwyth, Ceredigion, SY23 3EB, Wales, UK
| | - Barbara Hauck
- Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, Ceredigion, SY23 3EB, UK
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Plas Gogerddan, Aberystwyth, Ceredigion, SY23 3EB, Wales, UK
| | - Alexandra Lanot
- Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, Ceredigion, SY23 3EB, UK
- Department of Biology, University of York, Heslington, York, YO10 5DD, UK
| | - Michael K Theodorou
- Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, Ceredigion, SY23 3EB, UK
- Department of Agriculture and Environment, Agriculture Centre for Sustainable Energy Systems, Harper Adams University, Newport, Shropshire, TF10 8NB, UK
| | - Gordon Allison
- Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, Ceredigion, SY23 3EB, UK
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Plas Gogerddan, Aberystwyth, Ceredigion, SY23 3EB, Wales, UK
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