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Specific leaf metabolic changes paving the way to osmotic potential in four Quercus species in response to drought
  • Ismael Aranda,
  • Estrella Cadahia,
  • Brígida Fernández de Simón
Ismael Aranda
Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria
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Estrella Cadahia
Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria
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Brígida Fernández de Simón
Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria
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Abstract

Osmotic adjustment is recognized as an important mechanism of maintaining turgor under water stress. However, the metabolic basis of this process has been documented in some few forest tree species. The leaf water relations of four Quercus species were studied from P-V curves in well-watered (WW) and water-stressed (WS) seedlings. Lowest values of osmotic potential at full turgor (Ψπ100) followed the ranking Q. ilex < Q. faginea < Q. pyrenaica < Q. petraea. The leaf osmotic potential at the turgor loss point (ΨTLP) kept up with the patterns of the Ψπ100 across species and treatments. The leaf metabolome pointed out to the pool of carbohydrates, some organic acids, and cyclitols as main contributors to osmotic potential. Amino-acids, although very reactive to WS particularly in Q. pyrenaica accounted quantitatively less to osmotic potential than rest of the compounds. The relevance of proto-quercitol was high as a contributor to osmotic potential regardless treatment or species. Other metabolites as quinic acid played a more relevant role in osmoregulation specifically in Q. ilex. The study shows leaf osmotic potential is underpinned by a metabolic response shaped according to phylogenetic history and ecology of the species.