English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Open

Presents the pdf analysis as premium feature

PDF Analysis

Insights

Presents the summarisation as premium feature

Summarisation

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

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 ( F  v ) similar to black spruce, but higher photochemical efficiency ( F  v / F  m ), lower quantum yield, lower chlorophyll fluorescence (%), and higher thermal dissipation efficiency ( q  N ), although the seed-source effect and the seed-source × species interaction were significant only for  F  v / F  m . After low-temperature exposure (–40 °C), red spruce had significantly lower  F  v / F  m , quantum yield and  q  N  than black spruce, but higher chlorophyll fluorescence and relative fluorescence. Species, seed-source effect, and seed-source × 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 × 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.

Light-energy processing and freezing-tolerance traits in red spruce and black spruce: species and seed-source variation