Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): K. L. Fenn; F. C. MeinzerK. A. McCullohD. R. Woodruff; D. E. Marias
    Date: 2015
    Source: Tree Physiology. 35(5): 535-548.
    Publication Series: Scientific Journal (JRNL)
    Station: Pacific Northwest Research Station
    PDF: View PDF  (1.47 MB)

    Description

    First-year tree seedlings represent a particularly vulnerable life stage and successful seedling establishment is crucial for forest regeneration. We investigated the extent to which Pinus ponderosa P. & C. Lawson populations from different climate zones exhibit differential expression of functional traits that may facilitate their establishment. Seeds from two populations from sites with contrasting precipitation and temperature regimes east (PIPOdry) and west (PIPOmesic) of the Oregon Cascade mountains were sown in a common garden experiment and grown under two water availability treatments (control and drought). Aboveground biomass accumulation, vegetative phenology, xylem anatomy, plant hydraulic architecture, foliar stable carbon isotope ratios (δ13C), gas exchange and leaf water relations characteristics were measured. No treatment or population-related differences in leaf water potential were detected. At the end of the first growing season, aboveground biomass was 74 and 44% greater in PIPOmesic in the control and drought treatments, respectively. By early October, 73% of PIPOdry seedlings had formed dormant buds compared with only 15% of PIPOmesic seedlings. Stem theoretical specific conductivity, calculated from tracheid dimensions and packing density, declined from June through September and was nearly twice as high in PIPOmesic during most of the growing season, consistent with measured values of specific conductivity. Intrinsic water-use efficiency based on δ13C values was higher in PIPOdry seedlings for both treatments across all sampling dates. There was a negative relationship between values of δ13C and leaf-specific hydraulic conductivity across populations and treatments, consistent with greater stomatal constraints on gas exchange with declining seedling hydraulic capacity. Integrated growing season assimilation and stomatal conductance estimated from foliar δ13C values and photosynthetic CO2-response curves were 6 and 28% lower, respectively, in PIPOdry seedlings. Leaf water potential at the turgor loss point was 0.33 MPa more negative in PIPOdry, independent of treatment. Overall, PIPOdry seedlings exhibited more conservative behavior, suggesting reduced growth is traded off for increased resistance to drought and extreme temperatures.

    Publication Notes

    • You may send email to pnw_pnwpubs@fs.fed.us to request a hard copy of this publication.
    • (Please specify exactly which publication you are requesting and your mailing address.)
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

    Citation

    Kerr, K. L.; Meinzer, F. C.; McCulloh, K. A.; Woodruff, D. R.; Marias, D. E. 2015. Expression of functional traits during seedling establishment in two populations of Pinus ponderosa from contrasting climates. Tree Physiology. 35(5): 535-548.

    Cited

    Google Scholar

    Keywords

    carbon isotope discrimination, gas exchange, genetic variation, hydraulic architecture, osmotic potential, phenology.

    Related Search


    XML: View XML
Show More
Show Fewer
Jump to Top of Page
https://www.fs.usda.gov/treesearch/pubs/49804