TY - JOUR
T1 - The effect of water availability on the carbon and nitrogen isotope composition of a C4 plant (pearl millet, Pennisetum glaucum)
AU - Sanborn, Lily H.
AU - Reid, Rachel E.B.
AU - Bradley, Alexander S.
AU - Liu, Xinyi
N1 - Funding Information:
The authors thank Michael Dyer, Melanie Suess, Stephanie Moore, and the staff at the Goldfarb Plant Growth Facility at Washington University in St. Louis.
Funding Information:
This work was supported by the National Science Foundation [grant number 1826727] and the International Center for Energy, Environment, and Sustainability.
Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2021/8
Y1 - 2021/8
N2 - To evaluate the potential utility of isotope ratios in plant materials as an archaeological proxy for past crop water status, relationships between water availability and stable isotope ratios in C4 species must be established. This study quantified the isotopic values (δ13C and δ15N) of pearl millet (Pennisetum glaucum) seeds and leaves in response to varying degrees of water stress. Under greenhouse conditions, we exposed five strains of pearl millet to three different watering treatments. Pearl millet seed δ13C values (mean and SD = -13.9 ± 0.5‰, n = 48) and leaf δ13C values (mean and SD = -14.8 ± 0.7‰, n = 75) were positively correlated with water availability across 75 plants from five strains. The magnitude of the relationship for seeds (0.24 ± 0.04‰ per 0.1 m3 m−3 increase in soil moisture) and leaves (0.24 ± 0.06‰) was similar. The five strains showed differences in bulk carbon isotope ratios but had indistinguishable responses to water availability. Water availability had no discernible effect on δ15N in any of these strains. These results suggest that, while in some cases sensitive to water availability, the differences in the isotope ratios of pearl millet seeds and leaves across treatments were not of sufficient magnitude for reconstructing past crop water status without additional information.
AB - To evaluate the potential utility of isotope ratios in plant materials as an archaeological proxy for past crop water status, relationships between water availability and stable isotope ratios in C4 species must be established. This study quantified the isotopic values (δ13C and δ15N) of pearl millet (Pennisetum glaucum) seeds and leaves in response to varying degrees of water stress. Under greenhouse conditions, we exposed five strains of pearl millet to three different watering treatments. Pearl millet seed δ13C values (mean and SD = -13.9 ± 0.5‰, n = 48) and leaf δ13C values (mean and SD = -14.8 ± 0.7‰, n = 75) were positively correlated with water availability across 75 plants from five strains. The magnitude of the relationship for seeds (0.24 ± 0.04‰ per 0.1 m3 m−3 increase in soil moisture) and leaves (0.24 ± 0.06‰) was similar. The five strains showed differences in bulk carbon isotope ratios but had indistinguishable responses to water availability. Water availability had no discernible effect on δ15N in any of these strains. These results suggest that, while in some cases sensitive to water availability, the differences in the isotope ratios of pearl millet seeds and leaves across treatments were not of sufficient magnitude for reconstructing past crop water status without additional information.
KW - African millet
KW - Greenhouse experiment
KW - Palaeoenvironmental reconstruction
KW - Stable isotope analysis
KW - Water restriction
UR - http://www.scopus.com/inward/record.url?scp=85107680168&partnerID=8YFLogxK
U2 - 10.1016/j.jasrep.2021.103047
DO - 10.1016/j.jasrep.2021.103047
M3 - Article
AN - SCOPUS:85107680168
SN - 2352-409X
VL - 38
JO - Journal of Archaeological Science: Reports
JF - Journal of Archaeological Science: Reports
M1 - 103047
ER -