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Drought-induced shoot dieback starts with massive root xylem embolism and variable depletion of nonstructural carbohydrates in seedlings of two tree species.
- Source :
-
The New phytologist [New Phytol] 2017 Jan; Vol. 213 (2), pp. 597-610. Date of Electronic Publication: 2016 Aug 30. - Publication Year :
- 2017
-
Abstract
- Combining hydraulic- and carbon-related measurements helps to understand drought-induced plant mortality. Here, we investigated the role that plant respiration (R) plays in determining carbon budgets under drought. We measured the hydraulic conductivity of stems and roots, and gas exchange and nonstructural carbohydrate (NSC) concentrations of leaves, stems and roots of seedlings of two resprouting species exposed to drought or well-watered conditions: Ulmus minor (riparian tree) and Quercus ilex (dryland tree). With increasing water stress (occurring more rapidly in larger U. minor), declines in leaf, stem and root R were less pronounced than that in leaf net photosynthetic CO <subscript>2</subscript> uptake (P <subscript>n</subscript> ). Daytime whole-plant carbon gain was negative below -4 and -6 MPa midday xylem water potential in U. minor and Q. ilex, respectively. Relative to controls, seedlings exhibiting shoot dieback suffered c. 80% loss of hydraulic conductivity in both species, and reductions in NSC concentrations in U. minor. Higher drought-induced depletion of NSC reserves in U. minor was related to higher plant R, faster stomatal closure, and premature leaf-shedding. Differences in drought resistance relied on the ability to maintain hydraulic conductivity during drought, rather than tolerating conductivity loss. Root hydraulic failure elicited shoot dieback and precluded resprouting without root NSC reserves being apparently limiting for R.<br /> (© 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.)
- Subjects :
- Carbon metabolism
Cell Respiration
Gases metabolism
Plant Stems physiology
Plant Stomata physiology
Quercus physiology
Seedlings anatomy & histology
Seedlings growth & development
Species Specificity
Steam
Ulmus physiology
Water
Carbohydrates chemistry
Droughts
Plant Roots physiology
Plant Shoots physiology
Seedlings physiology
Trees physiology
Xylem physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1469-8137
- Volume :
- 213
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- The New phytologist
- Publication Type :
- Academic Journal
- Accession number :
- 27575435
- Full Text :
- https://doi.org/10.1111/nph.14150