co2

Carbon Dioxide Uptake in Grass Plants

The CO2 data frame has 84 rows and 5 columns of data from an experiment on the cold tolerance of the grass species Echinochloa crus-galli.

Keywords
datasets
Usage
CO2
Details

The $CO2$ uptake of six plants from Quebec and six plants from Mississippi was measured at several levels of ambient $CO2$ concentration. Half the plants of each type were chilled overnight before the experiment was conducted.

This dataset was originally part of package nlme, and that has methods (including for [, as.data.frame, plot and print) for its grouped-data classes.

Format

An object of class c("nfnGroupedData", "nfGroupedData", "groupedData", "data.frame") containing the following columns:

Plant
an ordered factor with levels Qn1 < Qn2 < Qn3 < ... < Mc1 giving a unique identifier for each plant.
Type
a factor with levels Quebec Mississippi giving the origin of the plant
Treatment
a factor with levels nonchilled chilled
conc
a numeric vector of ambient carbon dioxide concentrations (mL/L).
uptake
a numeric vector of carbon dioxide uptake rates ($umol/m^2$ sec).

Source

Potvin, C., Lechowicz, M. J. and Tardif, S. (1990) “The statistical analysis of ecophysiological response curves obtained from experiments involving repeated measures”, Ecology, 71, 1389--1400. Pinheiro, J. C. and Bates, D. M. (2000) Mixed-effects Models in S and S-PLUS, Springer.

Aliases
  • CO2
Examples
library(datasets) require(stats); require(graphics) coplot(uptake ~ conc | Plant, data = CO2, show.given = FALSE, type = "b") ## fit the data for the first plant fm1 <- nls(uptake ~ SSasymp(conc, Asym, lrc, c0), data = CO2, subset = Plant == "Qn1") summary(fm1) ## fit each plant separately fmlist <- list() for (pp in levels(CO2$Plant)) { fmlist[[pp]] <- nls(uptake ~ SSasymp(conc, Asym, lrc, c0), data = CO2, subset = Plant == pp) } ## check the coefficients by plant print(sapply(fmlist, coef), digits = 3)
Documentation reproduced from package datasets, version 3.0.3, License: Part of R 3.0.3

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