Cevc Ekgpv‡Ýec 46*3/5+<87/93. 4232 INTRACANOPY LEAF PLASTICITY IN FCET[QFGU GZEGNUC IN BISLEY EXPERIMENTALWATERSHEDS, PUERTO RICO Icdtkgnc Fqtkc, 3.4 . Octiq Hgtpcpfg¦/Dwtiqu 1 . Fcpc Rqygnn 3.5 cpf Lqtfcp Uejokfv 1 1 Department of Earth and Environmental Sciences, Wesleyan University, 265 Church Street, Middletown, CT 06459 2 Uejqqn qh Hqtguvt{ cpf Gpxktqpogpvcn Uvwfkgu. [cng Wpkxgtukv{. 195 Prospect Street, New Haven, CT 06511 3 Nicholas School of the Environment, Duke University, 308 Research Drive, Durham, NC 27708 *Corresponding author (mdoriaramire@wesleyan.edu). Inquiries can also be sent to a Wesleyan University faculty member, Tim Ku (tcku@wesleyan.edu), Dana Royer (droyer@wesleyan.edu), or Phillip Resor (presor@wesleyan.edu). Key words: leaf attributes, stomatal density, guard cells, upper canopy interior leaves, shade leaves, sun leaves ABSTRACT Charting the phenotypic plasticity of plants provides insights into plant ecology. Because leaves on a single tree share the same genetic composition, intracanopy study highlights the potential for environmentally responsive changes independent of genetic difference. Both hydraulic gradients and environmental factors such as irradiance, wind, and leaf temperature have been proposed as controls for intracanopy leaf-trait variation. To investigate the relative roles of these two factors, we report leaf area, leaf mass per area, stomatal density, and guard cell length along height and positioning (interior vs. exterior leaves along single branches) gradients for a single tree of the woody tropical species Fcet{qfgu gzegnuc (Burseraceae) in Bisley Experimental Watersheds, Puerto Rico. We Ýpf vjcv ngcxgu htqo itgcvgt jgkijvu ctg uocnngt cpf jcxg c jkijgt ngch ocuu rgt ctgc. jkijgt uvqocvcn fgpukv{. cpf uocnngt iwctf egnn ngpivj0 Kp eqpvtcuv. yg Ýpf hgy fkhhgtgpegu between interior and exterior leaves, with the exception of stomatal density. Because upper-crown leaves experience higher irradiance, wind speed, and temperature, our results support the idea that abiotic factors are more important than hydraulic gradients for controlling plasticity in our measured traits. RESUMEN El estudio de la plasticidad fenotípica en plantas aporta importante información sobre la ecología vegetal. Debido a que las hojas de un único árbol comparten la misma carga genética, la variación morfológica dentro del dosel representa el potencial de respuesta a cambios ambientales independiente de la diferencia genética. Tanto el gradiente hidráulico como factores abióticos tales como radición, viento, y temperatura foliar se han propuesto eqoq fgvgtokpcpvgu fg nc xctkcek„p kpvtcfqugn fg ectcevgt‡uvkecu hqnkctgu0 Eqp gn Ýp fg