drcSeedGerm (version 1.0.1)

GR_TPsi_models: Hydro-Thermal-time models based on the germination rate

Description

These models are used to describe the germination rate of a seed, depending on the environmental temperature and water potential.

Usage

GRTPsi.M()
GRTPsi.M.fun(Temp, Psi, k, Tb, ThetaHT, Psib)
GRTPsi.BS()
GRTPsi.BS.fun(Temp, Psi, k, Tb, To, ThetaHT, Psib)

Value

The 'GRT.M.fun()' functions returns a vector of responses, for given values of temperature, Tc, Tb and ThetaH. The GRT.M() function returns a list containing the nonlinear function, the self starter function, the parameter names and other items which are internally used by the 'drm()' function.

Arguments

Temp

Temperature variable

Psi

Water potential variable

Psib

Base water potential variable

k

regression parameter

Tb

base temperature

To

optimal temperature

ThetaHT

Hydro-thermal-time parameter

Author

Andrea Onofri

Details

The 'GRT.M.fun()' is a generic R function, while the GRT.M() function is meant to be used with the 'drm()' function, within the 'drc' package.

References

https://www.statforbiology.com/2023/stat_drcte_12-htt2step/

Examples

library(drcte)
Tval <- c(2, 5, 10, 15, 20, 25, 30, 35, 40)
GR <- c(0, 0, 0.209, 0.435, 0.759, 0.821, 0.417, 0.145, 0)
modM <- drm(GR ~ Tval, fct = GRT.M())
plot(modM, log="", xlim = c(0, 40), ylim=c(0,1.2),
     legendPos = c(5, 1.0), xlab = "Temperature (°C)")