Mechanisms contributing to seasonal homeostasis of minimum leaf water potential and predawn disequilibrium between soil and plant water potential in Neotropical savanna trees

Seasonal regulation of leaf water potential (ΨL) was studied in eight dominant woody savanna species growing in Brazilian savanna (Cerrado) sites that experience a 5-month dry season. Despite marked seasonal variation in precipitation and air saturation deficit (D), seasonal differences in midday mi...

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Autores principales: Bucci, Sandra Janet, Goldstein, Guillermo Hernan, Campanello, Paula Inés, Scholz, Fabián Gustavo
Publicado: 2005
Materias:
Hydraulic conductance
Nocturnal transpiration
Plant-water relations
Sap flow
Savannas
Biodiversity
Hydraulic conductivity
Physiology
Plants (botany)
Precipitation (meteorology)
Soils
Wetting
Air saturation deficit
architectural traits
Cerrado tree species
Isohydric behavior
Seasonal regulation
Stomatal conductance
Woody savanna species
Meteorology
Plants
Precipitants
Saturation
Seasonal Variation
Soil
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09311890_v19_n3_p296_Bucci
http://hdl.handle.net/20.500.12110/paper_09311890_v19_n3_p296_Bucci
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_09311890_v19_n3_p296_Bucci
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spelling paper:paper_09311890_v19_n3_p296_Bucci2023-06-08T15:52:55Z Mechanisms contributing to seasonal homeostasis of minimum leaf water potential and predawn disequilibrium between soil and plant water potential in Neotropical savanna trees Bucci, Sandra Janet Goldstein, Guillermo Hernan Campanello, Paula Inés Scholz, Fabián Gustavo Hydraulic conductance Nocturnal transpiration Plant-water relations Sap flow Savannas Biodiversity Hydraulic conductivity Physiology Plants (botany) Precipitation (meteorology) Soils Wetting Air saturation deficit architectural traits Cerrado tree species Isohydric behavior Nocturnal transpiration Seasonal regulation Stomatal conductance Woody savanna species Meteorology Biodiversity Meteorology Physiology Plants Precipitants Saturation Seasonal Variation Soil Seasonal regulation of leaf water potential (ΨL) was studied in eight dominant woody savanna species growing in Brazilian savanna (Cerrado) sites that experience a 5-month dry season. Despite marked seasonal variation in precipitation and air saturation deficit (D), seasonal differences in midday minimum ΨL were small in all of the study species. Water use and water status were regulated by a combination of plant physiological and architectural traits. Despite a nearly 3-fold increase in mean D between the wet and dry season, a sharp decline in stomatal conductance with increasing D constrained seasonal variation in minimum ΨL by limiting transpiration per unit leaf area (E). The leaf surface area per unit of sapwood area (LA/SA), a plant architectural index of potential constraints on water supply in relation to transpirational demand, was about 1.5-8 times greater in the wet season compared to the dry season for most of the species. The changes in LA/SA from the wet to the dry season resulted from a reduction in total leaf surface area per plant, which maintained or increased total leaf-specific hydraulic conductance (G t) during the dry season. The isohydric behavior of Cerrado tree species with respect to minimum ΨL throughout the year thus was the result of strong stomatal control of evaporative losses, a decrease in total leaf surface area per tree during the dry season, an increase in total leaf-specific hydraulic conductance, and a tight coordination between gas and liquid phase conductance. In contrast with the seasonal isohydric behavior of minimum ΨL, predawn ΨL in all species was substantially lower during the dry season compared to the wet season. During the dry season, predawn ΨL was more negative than bulk soil Ψ estimated by extrapolating plots of E versus ΨL to E=0. Predawn disequilibrium between plant and soil Ψ was attributable largely to nocturnal transpiration, which ranged from 15 to 22% of the daily total. High nocturnal water loss may also have prevented internal water storage compartments from being completely refilled at night before the onset of transpiration early in the day. © Springer-Verlag 2004. Fil:Bucci, S.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Goldstein, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Campanello, P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Scholz, F.G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2005 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09311890_v19_n3_p296_Bucci http://hdl.handle.net/20.500.12110/paper_09311890_v19_n3_p296_Bucci
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Hydraulic conductance
Nocturnal transpiration
Plant-water relations
Sap flow
Savannas
Biodiversity
Hydraulic conductivity
Physiology
Plants (botany)
Precipitation (meteorology)
Soils
Wetting
Air saturation deficit
architectural traits
Cerrado tree species
Isohydric behavior
Nocturnal transpiration
Seasonal regulation
Stomatal conductance
Woody savanna species
Meteorology
Biodiversity
Meteorology
Physiology
Plants
Precipitants
Saturation
Seasonal Variation
Soil
spellingShingle Hydraulic conductance
Nocturnal transpiration
Plant-water relations
Sap flow
Savannas
Biodiversity
Hydraulic conductivity
Physiology
Plants (botany)
Precipitation (meteorology)
Soils
Wetting
Air saturation deficit
architectural traits
Cerrado tree species
Isohydric behavior
Nocturnal transpiration
Seasonal regulation
Stomatal conductance
Woody savanna species
Meteorology
Biodiversity
Meteorology
Physiology
Plants
Precipitants
Saturation
Seasonal Variation
Soil
Bucci, Sandra Janet
Goldstein, Guillermo Hernan
Campanello, Paula Inés
Scholz, Fabián Gustavo
Mechanisms contributing to seasonal homeostasis of minimum leaf water potential and predawn disequilibrium between soil and plant water potential in Neotropical savanna trees
topic_facet Hydraulic conductance
Nocturnal transpiration
Plant-water relations
Sap flow
Savannas
Biodiversity
Hydraulic conductivity
Physiology
Plants (botany)
Precipitation (meteorology)
Soils
Wetting
Air saturation deficit
architectural traits
Cerrado tree species
Isohydric behavior
Nocturnal transpiration
Seasonal regulation
Stomatal conductance
Woody savanna species
Meteorology
Biodiversity
Meteorology
Physiology
Plants
Precipitants
Saturation
Seasonal Variation
Soil
description Seasonal regulation of leaf water potential (ΨL) was studied in eight dominant woody savanna species growing in Brazilian savanna (Cerrado) sites that experience a 5-month dry season. Despite marked seasonal variation in precipitation and air saturation deficit (D), seasonal differences in midday minimum ΨL were small in all of the study species. Water use and water status were regulated by a combination of plant physiological and architectural traits. Despite a nearly 3-fold increase in mean D between the wet and dry season, a sharp decline in stomatal conductance with increasing D constrained seasonal variation in minimum ΨL by limiting transpiration per unit leaf area (E). The leaf surface area per unit of sapwood area (LA/SA), a plant architectural index of potential constraints on water supply in relation to transpirational demand, was about 1.5-8 times greater in the wet season compared to the dry season for most of the species. The changes in LA/SA from the wet to the dry season resulted from a reduction in total leaf surface area per plant, which maintained or increased total leaf-specific hydraulic conductance (G t) during the dry season. The isohydric behavior of Cerrado tree species with respect to minimum ΨL throughout the year thus was the result of strong stomatal control of evaporative losses, a decrease in total leaf surface area per tree during the dry season, an increase in total leaf-specific hydraulic conductance, and a tight coordination between gas and liquid phase conductance. In contrast with the seasonal isohydric behavior of minimum ΨL, predawn ΨL in all species was substantially lower during the dry season compared to the wet season. During the dry season, predawn ΨL was more negative than bulk soil Ψ estimated by extrapolating plots of E versus ΨL to E=0. Predawn disequilibrium between plant and soil Ψ was attributable largely to nocturnal transpiration, which ranged from 15 to 22% of the daily total. High nocturnal water loss may also have prevented internal water storage compartments from being completely refilled at night before the onset of transpiration early in the day. © Springer-Verlag 2004.
author Bucci, Sandra Janet
Goldstein, Guillermo Hernan
Campanello, Paula Inés
Scholz, Fabián Gustavo
author_facet Bucci, Sandra Janet
Goldstein, Guillermo Hernan
Campanello, Paula Inés
Scholz, Fabián Gustavo
author_sort Bucci, Sandra Janet
title Mechanisms contributing to seasonal homeostasis of minimum leaf water potential and predawn disequilibrium between soil and plant water potential in Neotropical savanna trees
title_short Mechanisms contributing to seasonal homeostasis of minimum leaf water potential and predawn disequilibrium between soil and plant water potential in Neotropical savanna trees
title_full Mechanisms contributing to seasonal homeostasis of minimum leaf water potential and predawn disequilibrium between soil and plant water potential in Neotropical savanna trees
title_fullStr Mechanisms contributing to seasonal homeostasis of minimum leaf water potential and predawn disequilibrium between soil and plant water potential in Neotropical savanna trees
title_full_unstemmed Mechanisms contributing to seasonal homeostasis of minimum leaf water potential and predawn disequilibrium between soil and plant water potential in Neotropical savanna trees
title_sort mechanisms contributing to seasonal homeostasis of minimum leaf water potential and predawn disequilibrium between soil and plant water potential in neotropical savanna trees
publishDate 2005
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09311890_v19_n3_p296_Bucci
http://hdl.handle.net/20.500.12110/paper_09311890_v19_n3_p296_Bucci
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