Lisa Pedicino
M.S. 1997

Contact Information:

Ms. Lisa Pedicino
c/o Prof. Jon Pedicino
College of the Redwoods, Eureka Campus
7351 Tompkins Hill Road
Eureka, CA 95501
E-mail:c/o jon-pedicino@redwoods.edu


M.S. Thesis Title: CARBON ISTOPIC VARIATIONS IN 7 SOUTHWESTERN U.S. PLANTS FROM
HERBARIUM COLLECTIONS OF THE LAST 150 YEARS


School of Renewable Natural Resources
The University of Arizona

1997

 

Abstract

Since industrialization atmospheric CO2 concentrations have increased from 280 to 365 ppmv and d13Cair has decreased from -6.5 to -8.2 . These two trends have consequences for plant physiology. I examine d13Cplant and physiological parameters in herbarium specimens of Atriplex confertifolia, Atriplex canescens, Ephedra viridis, Pinus edulis, Pinus flexilis, Juniperus scopulorum, and Quercus turbinella. For all species, I found relatively high and unsystematic variability. d13C values for A. confertifolia and A. canescens varied by up to 7.9 and 9.5 respectively; d13C values of these C4 shrubs are unsuitable for reconstructing d13Cair, as previously claimed. d13Cplant generally becomes more depleted except inP. edulis. Other calculated parameters such as D, Ci/Ca, Ci, and A/g have varying responses even among similar functional groups. Because much of the isotopic variability caused by interplant, intertree, intersite, and interannual differences is implicit, herbarium specimens are inadequate for precise detection of direct CO2 effects on plant physiology.