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Rooting depth, water relations and non‐structural carbohydrate dynamics in three woody angiosperms differentially affected by an extreme summer drought
Author(s) -
Nardini Andrea,
Casolo Valentino,
Dal Borgo Anna,
Savi Tadeja,
Stenni Barbara,
Bertoncin Paolo,
Zini Luca,
McDowell Nathan G.
Publication year - 2016
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12646
Subject(s) - xylem , biology , botany , water transport , woody plant , hydraulic conductivity , growing season , soil water , horticulture , ecology , environmental science , agronomy , water flow , soil science
In 2012, an extreme summer drought induced species‐specific die‐back in woody species in Northeastern Italy. Quercus pubescens and Ostrya carpinifolia were heavily impacted, while Prunus mahaleb was largely unaffected. By comparing seasonal changes in isotopic composition of xylem sap, rainfall and deep soil samples, we show that P. mahaleb has a deeper root system than the other two species. This morphological trait allowed P mahaleb to maintain higher water potential (Ψ), gas exchange rates and non‐structural carbohydrates content (NSC) throughout the summer, when compared with the other species. More favourable water and carbon states allowed relatively stable maintenance of stem hydraulic conductivity (k) throughout the growing season. In contrast, in Quercus pubescens and Ostrya carpinifolia , decreasing Ψ and NSC were associated with significant hydraulic failure, with spring‐to‐summer k loss averaging 60%. Our data support the hypothesis that drought‐induced tree decline is a complex phenomenon that cannot be modelled on the basis of single predictors of tree status like hydraulic efficiency, vulnerability and carbohydrate content. Our data highlight the role of rooting depth in seasonal progression of water status, gas exchange and NSC, with possible consequences for energy‐demanding mechanisms involved in the maintenance of vascular integrity.