Geographic variation in resin canal defenses in seedlings from the Sitka spruce × white spruce introgression zone

Abstract

Seedlings from 18 provenances along a coast-interior transect in the Picea sitchensis (Bong.) Carrière × Picea glauca (Moench) Voss introgression zone in northwestern British Columbia were mechanically wounded at the beginning of their third growing season to simulate natural attack by the white pine weevil, Pissodes strobi (Peck). Constitutive resin canals (CRC) in the cortex and traumatic resin canals (TRC) in the xylem of terminal shoots were characterized microscopically 4 months after wounding. Wounding resulted in a large increase in CRC size and in TRC number and density. Provenances differed significantly in TRC number and in CRC number, size, total area, and the proportion of total bark area occupied by CRC. CRC number and size, TRC number, and provenance weevil resistance (obtained from previously published data) increased with increasing latitude, elevation, and distance from the Pacific Ocean (i.e., towards the P. glauca end of the introgression zone) and decreased with increasing longitude (i.e., towards P. sitchensis). These traits also increased with aridity and continentality and decreased with most temperature, precipitation, and growing season length variables. Statistically significant multiple regression models related variation in some resin canal traits to geographic (r 2 = 0.71) and climatic (r 2 = 0.62) variables. Provenance mean values for weevil resistance were positively associated with predicted values for TRC number and CRC size. These results indicate that it is possible to predict locations in the introgression zone containing trees that possess desirable resin canal traits using geographic or climatic variables.Résumé : Des semis de 18 provenances récoltées le long d'un transect allant de la région côtière vers l'intérieur des terres, dans la zone d'introgression de Picea sitchensis (Bong.) Carrière × Picea glauca (Moench) Voss située dans le nord-ouest de la Colombie-Britannique, ont été blessés mécaniquement au début de la troisième saison de croissance pour simuler une attaque par le charançon du pin blanc, Pissodes strobi (Peck). Quatre mois plus tard, les caractéristi-ques microscopiques des canaux résinifères constitutifs (CRC) présents dans le cortex et les canaux résinifères d'origine traumatique (CRT) formés dans le xylème des pousses terminales ont été examinées. La dimension des CRC ainsi que le nombre et la densité des CRT ont beaucoup augmenté suite aux blessures. Le nombre de CRT ainsi que le nombre, la dimension, la surface totale et la proportion de la surface totale d'écorce occupée par les CRC diffèrent significativement selon les provenances. Le nombre et la dimension des CRC, le nombre de CRT et la résistance des provenances au charançon (obtenue à partir de données déjà publiées) augmentent avec la latitude, l'altitude et la distance de l'océan Pacifique (i.e., vers le côté de P. glauca dans la zone d'introgression) et diminuent avec l'augmentation de la longitude (i.e., vers P. sitchensis). Ces caractères augmentent également avec le degré d'aridité et de cont...

Genetic resistance of Sitka spruce (Picea sitchensis) populations to the white pine weevil (Pissodes strobi): distribution of resistance

“…In the hybridization zone of Sitka-white spruce in north-west BC, O'Neill et al (2002) reported a strong traumatic resin formation in white spruce in response to wounding (as has been previously noted in other populations of this species (Alfaro, 1995;Tomlin et al, 1998)) compared with Sitka spruce (O'Neill et al, 2002). The most significant independent variable for predicting traumatic resin cells in trees was distance from the sea (O'Neill et al, 2002) which equates to the degree of white spruce genotypes in the hybrid mix; populations further from the sea have a greater proportion of white spruce.…”

Influence of climate variables on resin yield and secretory structures in tapped Pinus pinaster Ait. in central Spain

“…In P. taeda, peak resin flows appeared to be associated with moderate water deficit periods (Ruel et al, 1998;Lombardero et al, 2000). Furthermore, earlier studies on Pinaceae xylem anatomy showed that harsh environmental conditions such as high temperatures, aridity and cold winters are associated with higher frequencies and greater sizes of resin canals (Zamski, 1972;Rigling et al, 2003;Martín et al, 2010;Esteban et al, 2010), whereas an increment of annual or summer rainfall is negatively correlated with these traits (Wimmer and Grabner, 1997;O'Neill et al, 2002). Thus it is also hypothesized that constitutive and traumatic resin canal formation and de novo resin synthesis processes will be influenced by the climate characteristics of the current and the previous year.…”

Forest health and climate change: A British Columbia perspective

“…Planting species and populations (seedlots) that are adapted to future climates preserves the host-pest balance that has been created over millennia. Provenance tests reveal that the incidence of pest attack increases sharply when populations are planted in climates that differ significantly from their origin (O'Neill et al 2002). The facilitated migration of tree species provides an opportunity to increase stand resiliency and reduce susceptibility to pests.…”