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Title: Plant Water Deficits, Osmotic Properties, and Hydraulic Resistances of Hawaiian Dubautia Species from Adjacent Bog and Wet-Forest Habitats
Authors: Canfield, Joan E.
Issue Date: Oct-1990
Publisher: University of Hawaii Press
Citation: Canfield JE. 1990. Plant water deficits, osmotic properties, and hydraulic resistances of Hawaiian Dubautia species from adjacent bog and wet-forest habitats. Pac Sci 44(4): 449-455.
Abstract: Functional responses of two closely related Dubautia species from
a mosaic of Hawaiian bogs and wet forest were compared to help explain their
differential distributions. Dubautia paleata is largely restricted to saturated bogs,
while D. raillardioides is restricted to the surrounding, better-drained wet forest.
Minimum diurnal tissue water potentials of D. paleata are significantly lower
than those of D. raillardioides, despite the moister condition of bog soil. The tissue
osmotic potential at full hydration of D. paleata is significantly lower than
that of D. raillardioides. As a result, the tissue water potential at which turgor
reaches zero for D. paleata is significantly lower than that of D. raillardioides.
Dubautia paleata is thus able to maintain positive turgor to lower water potentials
than D. raillardioides. Lack of a lowered, in D. raillardioides may therefore
contribute to exclusion of that species from the bog habitat. Preliminary data
suggest a significantly greater hydraulic resistance for D. paleata than for D.
raillardioides, probably due to higher root resistance caused by the reduced
condition of the waterlogged bog substrate. The difference in hydraulic resistance
could help account for the contrasting water deficits of the two species.
ISSN: 0030-8870
Appears in Collections:Pacific Science Volume 44, Number 4, 1990

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