Constraints on physiological function associated with branch architecture and wood density in tropical forest trees.

Published

Journal Article

This study examined how leaf and stem functional traits related to gas exchange and water balance scale with two potential proxies for tree hydraulic architecture: the leaf area:sapwood area ratio (A(L):A(S)) and wood density (rho(w)). We studied the upper crowns of individuals of 15 tropical forest tree species at two sites in Panama with contrasting moisture regimes and forest types. Transpiration and maximum photosynthetic electron transport rate (ETR(max)) per unit leaf area declined sharply with increasing A(L):A(S), as did the ratio of ETR(max) to leaf N content, an index of photosynthetic nitrogen-use efficiency. Midday leaf water potential, bulk leaf osmotic potential at zero turgor, branch xylem specific conductivity, leaf-specific conductivity and stem and leaf capacitance all declined with increasing rho(w). At the branch scale, A(L):A(S) and total leaf N content per unit sapwood area increased with rho(w), resulting in a 30% increase in ETR(max) per unit sapwood area with a doubling of rho(w). These compensatory adjustments in A(L):A(S), N allocation and potential photosynthetic capacity at the branch level were insufficient to completely offset the increased carbon costs of producing denser wood, and exacerbated the negative impact of increasing rho(w) on branch hydraulics and leaf water status. The suite of tree functional and architectural traits studied appeared to be constrained by the hydraulic and mechanical consequences of variation in rho(w).

Full Text

Cited Authors

  • Meinzer, FC; Campanello, PI; Domec, J-C; Genoveva Gatti, M; Goldstein, G; Villalobos-Vega, R; Woodruff, DR

Published Date

  • November 2008

Published In

Volume / Issue

  • 28 / 11

Start / End Page

  • 1609 - 1617

PubMed ID

  • 18765366

Pubmed Central ID

  • 18765366

Electronic International Standard Serial Number (EISSN)

  • 1758-4469

International Standard Serial Number (ISSN)

  • 0829-318X

Digital Object Identifier (DOI)

  • 10.1093/treephys/28.11.1609

Language

  • eng