How strong is intracanopy leaf plasticity in temperate deciduous trees?

Abstract

Intracanopy plasticity in tree leaf form is a major determinant of whole-plant function and potentially of forest understory ecology. However, there exists little systematic information for the full extent of intracanopy plasticity, whether it is linked with height and exposure, or its variation across species. For arboretum-grown trees of six temperate deciduous species averaging 13-18 m in height, we quantified intracanopy plasticity for 11 leaf traits across three canopy locations (basal-interior, basal-exterior, and top). Plasticity was pronounced across the canopy, and maximum likelihood analyses indicated that plasticity was primarily linked with irradiance, regardless of height. Intracanopy plasticity (the quotient of values for top and basal-interior leaves) was often similar across species and statistically indistinguishable across species for several key traits. At canopy tops, the area of individual leaves was on average 0.5-0.6 times that at basal-interior, stomatal density 1.1-1.5 times higher, sapwood cross-sectional area up to 1.7 times higher, and leaf mass per area 1.5-2.2 times higher; guard cell and stomatal pore lengths were invariant across the canopy. Species differed in intracanopy plasticity for the mass of individual leaves, leaf margin dissection, ratio of leaf to sapwood areas, and stomatal pore area per leaf area; plasticity quotients ranged only up to ≈2. Across the six species, trait plasticities were uncorrelated and independent of the magnitude of the canopy gradient in irradiance or height and of the species' light requirements for regeneration. This convergence across species indicates general optimization or constraints in development, resulting in a bounded plasticity that improves canopy performance.

Efecto de la fragmentación en la morfometría foliar y el ambiente de Quercus germana Schldl. & Cham. (Fagaceae) en Xalapa, Veracruz

“…Las especies de Quercus manifiestan cambios morfológicos como respuesta a la variación en las condiciones ambientales de los sitios donde se desarrollan (Cardillo & Bernal, 2006;Li, Zhang, Liu, Luukkanen, & Berninger 2006;Sack, Melcher, Liu, Middleton, & Pardee, 2006). El género Quercus se considera con alta plasticidad fenotípica y gran parte de su variación fenotípica se asocia con características biológicas intrínsecas como los ciclos de vida largos, polinización anemógama, entrecruzamiento e hibridación (González-Rodríguez & Oyama, 2005;Tovar-Sánchez & Oyama, 2004).…”

“…El género Quercus se considera con alta plasticidad fenotípica y gran parte de su variación fenotípica se asocia con características biológicas intrínsecas como los ciclos de vida largos, polinización anemógama, entrecruzamiento e hibridación (González-Rodríguez & Oyama, 2005;Tovar-Sánchez & Oyama, 2004). La variación morfológica de las hojas de Quercus es de gran interés debido a que muchas especies están sometidas a una fuerte presión de selección local, que las ha llevado a la diferenciación entre poblaciones e individuos (González-Rodríguez & Oyama, 2005;TovarSánchez & Oyama, 2004;Sack et al, 2006). Las hojas son el principal órgano fotosintético de las plantas, lo que las hace altamente sensibles a cambios en la luz (Álvarez, Sánchez-González, & Granados-Sánchez, 2009;Halloy & Mark, 1996), ciclos fenológicos, ritmos de crecimiento (González-Rodríguez & Oyama, 2005;Nikolic, Krstic, Pajevic, & Orlovic, 2006), época del año y posición de la hoja en el árbol (Ponton, Dupoguey, & Dreyer, 2004).…”

“…The species of Quercus present morphological changes as a response to variation in the environmental conditions of the locations where they grow (Cardillo & Bernal, 2006;Li, Zhang, Liu, Luukkanen, & Berninger 2006;Sack, Melcher, Liu, Middleton, & Pardee, 2006). The genus Quercus is considered as having a high phenotypic plasticity and a large part of its phenotypic variation is associated with intrinsic biological characteristics such as long life cycles, wind pollination, crossing-over and hybridization (González-Rodríguez & Oyama, 2005;Tovar-Sánchez & Oyama, 2004).…”

Leaf Morphological Plasticity of Tree Species from Two Developmental Stages in Araucaria Forest

“…Although the knowledge about the shade tolerance of the plants goes back to the 18th century, there are still controversies about what are the main morphological traits of tolerant species (Niinemets 2006). The knowledge about the adaptations to shade conditions is based mainly on the development of seedlings and the observed patterns are influenced by the interspecific variation of seed size (Sack et al 2006;Valladares and Niinemets 2008). …”

Comment on “Functional Traits and Niche-Based Tree Community Assembly in an Amazonian Forest”

“…Yet traits can vary 2-to 3-fold or more across ontogeny or light environment within a species, whereas the interspecific range within a community is similar or only moderately higher (2)(3)(4)(5). This is not true for all traits (seed size varies intraspecifically, but not ontogenetically, and maximum size is a species-level trait), but for the traits related to leaf size, structure, and chemistry, intraspecific variation can be substantial.…”