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Anatomical changes with needle length are correlated with leaf structural and physiological traits across five Pinus species
Author(s) -
Wang Na,
Palmroth Sari,
Maier Christopher A.,
Domec JeanChristophe,
Oren Ram
Publication year - 2019
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.13516
Subject(s) - pinus <genus> , biology , photosynthesis , botany , photosynthetic capacity , range (aeronautics) , stomatal conductance , materials science , composite material
Abstract The genus Pinus has wide geographical range and includes species that are the most economically valued among forest trees worldwide. Pine needle length varies greatly among species, but the effects of needle length on anatomy, function, and coordination and trade‐offs among traits are poorly understood. We examined variation in leaf morphological, anatomical, mechanical, chemical, and physiological characteristics among five southern pine species: Pinus echinata , Pinus elliottii , Pinus palustris , Pinus taeda , and Pinus virginiana . We found that increasing needle length contributed to a trade‐off between the relative fractions of support versus photosynthetic tissue (mesophyll) across species. From the shortest (7 cm) to the longest (36 cm) needles, mechanical tissue fraction increased by 50%, whereas needle dry density decreased by 21%, revealing multiple adjustments to a greater need for mechanical support in longer needles. We also found a fourfold increase in leaf hydraulic conductance over the range of needle length across species, associated with weaker upward trends in stomatal conductance and photosynthetic capacity. Our results suggest that the leaf size strongly influences their anatomical traits, which, in turn, are reflected in leaf mechanical support and physiological capacity.