Canadian Forest Service Publications

Light-energy processing and freezing-tolerance traits in red spruce and black spruce: species and seed-source variation. 2003. Major, J.E.; Barsi, D.C.; Mosseler, A.; Campbell, M.; Rajora, O.P. Tree Physiology 23: 685-694.

Year: 2003

Issued by: Atlantic Forestry Centre

Catalog ID: 22800

Language: English

CFS Availability: Order paper copy (free)

Mark record


Red spruce (Picea rubens Sarg.) and black spruce (Picea mariana (Mill.) B.S.P.) are genetically and morphologically similar but ecologically distinct species. We determined intraspecific seed-source and interspecific variation of red spruce and black spruce, from across the near-northern margins of their ranges, for several light-energy processing and freezing-tolerance adaptive traits. Before exposure to low temperature, red spruce had variable fluorescence (Fv) similar to black spruce, but higher photochemical efficiency (Fv/Fm), lower quantum yield, lower chlorophyll fluorescence (%), and higher thermal dissipation efficiency (qn), although the seed-source effect and the seed0source x species interaction were significant only for Fv/Fm. After low-temperature exposure (-40 C), red spruce had significantly lower Fv/Fm quantum yield and qN than black spruce, but higher chlorophyll fluorescence and relative fluorescence. Species, seed-source effect, and seed-source x species interaction were consistent with predictions based on genetic (e.g., geographic) origins. Multi-temperature exposures (5, -20 and -40 C) often produced significant species and temperature effects, and species x temperature interactions as a result of species-specific responses to temperature exposures. The inherent physiological species-specific adaptations of red spruce and black spruce were largely consistent with a shade-tolerant, late-successional species and an early successional species, respectively. Species differences in physiological adaptations conform to a biological trade-off, probably as a result of natural selection pressure in response to light availability and prevailing temperature gradients.