How Plants Cope with Water Stress in the Field? Photosynthesis and Growth |
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Authors: | CHAVES M M; PEREIRA J S; MAROCO J; RODRIGUES M L; RICARDO C P P; OSORIO M L; CARVALHO I; FARIA T; PINHEIRO C |
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Institution: | 1Instituto Superior de Agronomia, Universidade Técnica Lisboa, Tapada da Ajuda, 1349017 Lisboa, Portugal, 2Instituto de Tecnologia Química e Biológica, Apartado 127, 2781901 Oeiras, Portugal, 3Universidade do Algarve, Faro, Portugal, 4Laboratório Químico Central Rebelo da Silva, Lisboa, Portugal and 5Instituto Superior de Psicologia Aplicada, Lisboa, Portugal |
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Abstract: | Plants are often subjected to periods of soil and atmosphericwater deficit during their life cycle. The frequency of suchphenomena is likely to increase in the future even outside todaysarid/semi-arid regions. Plant responses to water scarcity arecomplex, involving deleterious and/or adaptive changes, andunder field conditions these responses can be synergisticallyor antagonistically modified by the superimposition of otherstresses. This complexity is illustrated using examples of woodyand herbaceous species mostly from Mediterranean-type ecosystems,with strategies ranging from drought-avoidance, as in winter/springannuals or in deep-rooted perennials, to the stress resistanceof sclerophylls. Differences among species that can be tracedto different capacities for water acquisition, rather than todifferences in metabolism at a given water status, are described.Changes in the root : shoot ratio or the temporaryaccumulation of reserves in the stem are accompanied by alterationsin nitrogen and carbon metabolism, the fine regulation of whichis still largely unknown. At the leaf level, the dissipationof excitation energy through processes other than photosyntheticC-metabolism is an important defence mechanism under conditionsof water stress and is accompanied by down-regulation of photochemistryand, in the longer term, of carbon metabolism. |
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Keywords: | Carbon assimilation high temperature stress Lupinus photosynthesis Quercus ilex Quercus suber stomatal functioning Vitis vinifera water-stress xanthophyll cycle |
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