Photosynthesis in black and red spruce and their hybrid derivatives: ecological isolation and hybrid adaptive inferiority

Abstract

Photosynthetic response5 of black and red spruce were used to define parameters of their fundamental niches. Grown at warm temperature, black spruce had highest rates of CO₂ uptake at high light intensities, fitting it for a pioneering role, while red spruce had the lowest light compensation point, fitting it for a late successional role. Black and red spruce responded in different ways to low temperature acclimation. Low temperature, low light (12°C, 100 ft-c (1 ft-c = 10.7641x)) acclimation stimulated C0₂ uptake in black spruce under all conditions while it depressed CO₂ uptake in red spruce relative to rates following high temperature (26°C) acclimation. Niches defined by photosynthetic responses corresponded to observed habitats in the area of sympatry of black and red spruce and demonstrated the existence of ecological isolation, a premating restriction to hybridization.

Citation

Manley, S.A.M; Ledig, F. Thomas. 1979. Photosynthesis in black and red spruce and their hybrid derivatives: ecological isolation and hybrid adaptive inferiority. Canadian Journal of Botany 57(4):305-314