secalonic {drc}R Documentation

Root length

Description

Data are from an experiment assessing the inhibitory effect of secalonic acids on plant growth.

Usage

data(secalonic)

Format

A data frame with 7 observations on the following 2 variables:

dose
a numeric vector containing dose values
rootl
a numeric vector containing average root lengths

Details

Data are averages of three root length measurements.

Source

Gong, X. and Zeng, R. and Luo, S. and Yong, C. and Zheng, Q. (2004) Two new secalonic acids from Aspergillus Japonicus and their allelopathic effects on higher plants, Proceedings of International Symposium on Allelopathy Research and Application, 27-29 April, Shanshui, Guangdong, China (Editors: R. Zeng and S. Luo), 209–217.

Examples


## Fitting a four-parameter log-logistic model
secalonic.m1 <- drm(rootl ~ dose, data = secalonic, fct = LL.4())
summary(secalonic.m1)

## Fitting a three-parameter log-logistic model
##  lower limit fixed at 0
secalonic.m2 <- drm(rootl ~ dose, data = secalonic, fct = LL.3())
summary(secalonic.m1)

## Fitting logistic and log-logistic models
secalonic.m1 <- drm(rootl ~ dose, data = secalonic, fct = LL.4())
secalonic.m2 <- drm(rootl ~ dose, data = secalonic, fct = L.4())

plot(secalonic.m1, conLevel=0.001, broken=TRUE, ylim=c(0,7), xlab="Dose", ylab="Root length", cex=1.2, lwd=2)
plot(secalonic.m2, conLevel=0.001, broken=TRUE, ylim=c(0,7), add=TRUE, lty=2, lwd=2)

abline(h=coef(secalonic.m2)[3], lty=3, lwd=2)


[Package drc version 1.6-1 Index]