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Hydraulic and photosynthetic co‐ordination in seasonally dry tropical forest trees
Author(s) -
Brodribb T. J.,
Holbrook N. M.,
Gutiérrez M. V.
Publication year - 2002
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 - 10.1046/j.1365-3040.2002.00919.x
Subject(s) - evergreen , deciduous , dry season , photosynthesis , biology , botany , wet season , tropical and subtropical dry broadleaf forests , photosynthetic capacity , stomatal conductance , phenology , agronomy , horticulture , ecology
In the present study the linkage between hydraulic, photosynthetic and phenological properties of tropical dry forest trees were investigated. Seasonal patterns of stem‐specific conductivity ( K SP ) described from 12 species, including deciduous, brevi‐deciduous and evergreen species, indicated that only evergreen species were consistent in their response to a dry‐to‐wet season transition. In contrast, K SP in deciduous and brevi‐deciduous species encompassed a range of responses, from an insignificant increase in K SP following rains in some species, to a nine‐fold increase in others. Amongst deciduous species, the minimum K SP during the dry season ranged from 6 to 56% of wet season K SP, indicating in the latter case that a significant portion of the xylem remained functional during the dry season. In all species and all seasons, leaf‐specific stem conductivity ( K L ) was strongly related to the photosynthetic capacity of the supported foliage, although leaf photosynthesis became saturated in species with high K L . The strength of this correlation was surprising given that much of the whole‐plant resistance appears to be in the leaves. Hydraulic capacity, defined as the product of K L and the soil–leaf water potential difference, was strongly correlated with the photosynthetic rate of foliage in the dry season, but only weakly correlated in the wet season.