drc (version 1.6-1)

secalonic: Root length

Description

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

Usage

data(secalonic)

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.

Details

Data are averages of three root length measurements.

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)