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

Powers, Matthew D.; Pregitzer, Kurt S.; Palik, Brian J.

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

2008

Powers, Matthew D. | Pregitzer, Kurt S. | Palik, Brian J.

Stable isotope ratios of carbon (δ13C) and oxygen (δ18O) 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 δ13C and δ18O 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 δ13C from closed-canopy controls to thinned plots to 0.3 ha canopy gaps, and no change in δ18O between overstory environments. δ13C of P. resinosa and P. strobus was greater than δ13C of P. banksiana in whole foliage and holocellulose samples, and there were no differences in δ18O 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.

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