Reduction of transpiration and altered nutrient allocation contribute to nutrient decline of crops grown in elevated CO2 concentrations
Article first published online: 3 OCT 2012
© 2012 Blackwell Publishing Ltd
Plant, Cell & Environment
Volume 36, Issue 3, pages 697–705, March 2013
How to Cite
MCGRATH, J. M. and LOBELL, D. B. (2013), Reduction of transpiration and altered nutrient allocation contribute to nutrient decline of crops grown in elevated CO2 concentrations. Plant, Cell & Environment, 36: 697–705. doi: 10.1111/pce.12007
- Issue published online: 28 JAN 2013
- Article first published online: 3 OCT 2012
- Accepted manuscript online: 3 SEP 2012 08:43AM EST
- Received 22 May 2012; received in revised form 17 August 2012; accepted for publication 20 August 2012
Figure S1. Comparison between results of this study and Loladze (2002) for wheat grain. Data are mean percentage change with 95% confidence limits.
Figure S2. Comparison between results of this study and Loladze (2002) for leaves of all species. Data are mean percentage change with 95% confidence limits.
Figure S3. Intercepts and slopes for the regression of change in nutrient concentration versus percentage acquired through mass flow using a hierarchical model. Regressions were performed on the whole data set or by breaking the data into levels of tissues or species. Estimates of mass flow from three studies were used for comparison (Gregory et al. 1979, square; Clarkson 1981, circle; Oliveira et al. 2010, triangle). Points are the parameter estimate using the original data. Error bars are bias-corrected 95% confidence limits from bootstrapping. Values in parentheses are the number of nutrients used for the three mass flow studies. These varied because the studies measured different nutrients.
Table S1. Nutrient acquisition values used in the regressions. Oliveira et al. (2010) examined plants in two water potential treatments; the unstressed treatment was used here. Studies measured the total amount of each nutrient within the plant, and determined the amount transported to the root by mass flow as the concentration of the nutrient in soil water (g m3) multiplied by the volume of water transpired (m3). It was assumed that the amount of each nutrient in a plant that could have been supplied by mass flow was supplied by mass flow, i.e. the amount in the plant was divided by the amount delivered. Because a molecule transported to the root is not necessarily taken up by the root, this value can exceed 100% if the amount transported exceeds the amount absorbed. Thus in the regression analysis, values were capped at 100% as an estimate of the percent of the nutrient acquired by mass flow.
Table S2. Between-group heterogeneity (Qb) for CO2 effect size versus percentage of uptake acquired through mass flow across species or portion of plant using a hierarchical model. The analysis was performed three times for each categorical variable (mass flow or portion of plant), using estimates of mass flow from three different studies. * P < 0.10, ** P < 0.05, *** P < 0.001.
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