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Within‐crown plasticity in leaf traits among the tallest conifers
Author(s) -
Chin Alana R. O.,
Sillett Stephen C.
Publication year - 2019
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/ajb2.1230
Subject(s) - biology , abiotic component , crown (dentistry) , acclimatization , botany , phenotypic plasticity , context (archaeology) , abiotic stress , sequoia , ecology , medicine , paleontology , biochemistry , dentistry , gene
Premise of the study Leaves are the sites of greatest water stress in trees and a key means of acclimation to the environment. We considered phenotypic plasticity of Pseudotsuga menziesii leaves in their ecological context, exploring responsiveness to natural gradients in water stress (indicated by sample height) and light availability (measured from hemispherical photos) to understand how leaf structure is controlled by abiotic factors in tall tree crowns. Methods After measuring anatomy, morphology, and carbon isotope composition (δ 13 C) of leaves throughout crowns of P. menziesii >90 m tall, we compared structural plasticity of leaves among the three tallest conifer species using equivalent data from past work on Sequoia sempervirens and Picea sitchensis . Key results Leaf mass per projected area ( LMA ) and δ 13 C increased and mesoporosity (airspace/area) decreased along the water‐stress gradient, while light did not play a detectable role in leaf development. Overall, leaves of P. menziesii were far less phenotypically responsive to within‐crown abiotic gradients than either P. sitchensis , whose leaves responded strongly to light availability, or S. sempervirens , whose leaves responded equally strongly to water stress. Conclusions P. menziesii maintain remarkably consistent leaf structure despite pronounced vertical gradients in abiotic factors. Contrasting patterns of leaf structural plasticity underlie divergent ecological strategies of the three tallest conifer species, which coexist in Californian rainforests.