δ 13C and δ 18O Trends Across Overstory Environments in Whole Foliage and Cellulose of Three Pinus Species

• Published in: Journal of the American Society for Mass Spectrometry 2008-09, Vol.19 (9), p.1330-1335
• Main Authors: Powers, Matthew D., Pregitzer, Kurt S., Palik, Brian J.
• Format: Article
• Language: English
• ISSN: 1044-0305; 1879-1123
• DOI: 10.1016/j.jasms.2008.06.010

Stable isotope ratios of carbon (δ 13C) and oxygen (δ 18O) are increasingly used to investigate environmental influences on plant physiology. Cellulose is often isolated for isotopic studies, but some authors have questioned the value of this process. We studied trends in δ 13C and δ 18O of whole foliage and holocellulose from seedlings of three Pinus species across three overstory environments to evaluate the benefits of holocellulose extraction in the context of a traditional ecological experiment. Both tissue types showed increasing δ 13C from closed-canopy controls to thinned plots to 0.3 ha canopy gaps, and no change in δ 18O between overstory environments. δ 13C of P. resinosa and P. strobus was greater than δ 13C of P. banksiana in whole foliage and holocellulose samples, and there were no differences in δ 18O associated with species in either tissue type. Our results suggest whole foliage and holocellulose provide similar information about isotopic trends across broad environmental gradients and between species, but holocellulose may be better suited for studying differences in stable isotope composition between multiple species across several treatments. δ 13C and δ 18O from whole foliage and holocellulose showed similar trends among overstory environments, suggesting these substrates provide similar physiological information for stable isotope ecologists.