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Dynamics of leaf water relations components in co‐occurring iso‐ and anisohydric conifer species
Author(s) -
MEINZER FREDERICK C.,
WOODRUFF DAVID R.,
MARIAS DANIELLE E.,
MCCULLOH KATHERINE A.,
SEVANTO SANNA
Publication year - 2014
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.12327
Subject(s) - turgor pressure , shoot , osmotic pressure , biology , botany , horticulture
Because iso‐ and anisohydric species differ in stomatal regulation of the rate and magnitude of fluctuations in shoot water potential, they may be expected to show differences in the plasticity of their shoot water relations components, but explicit comparisons of this nature have rarely been made. We subjected excised shoots of co‐occurring anisohydric J uniperus monosperma and isohydric P inus edulis to pressure‐volume analysis with and without prior artificial rehydration. In J. monosperma , the shoot water potential at turgor loss ( Ψ TLP ) ranged from −3.4 MPa in artificially rehydrated shoots to −6.6 MPa in shoots with an initial Ψ of −5.5 MPa , whereas in P . edulis mean Ψ TLP remained at ∼ −3.0 MPa over a range of initial Ψ from −0.1 to −2.3 MPa . The shoot osmotic potential at full turgor and the bulk modulus of elasticity also declined sharply with shoot Ψ in J . monosperma , but not in P . edulis . The contrasting behaviour of J. monosperma and P . edulis reflects differences in their capacity for homeostatic regulation of turgor that may be representative of aniso‐ and isohydric species in general, and may also be associated with the greater capacity of J . monosperma to withstand severe drought.