FWSaturated {pvldcurve}

Saturated fresh weight estimation

Description

Calculates saturated fresh weight by fitting fresh weight values above the turgor loss point linearly to water potential values.

Usage

FWSaturated(data, sample = "sample",
  water.potential = "water.potential", fresh.weight = "fresh.weight",
  dry.weight = "dry.weight")

Arguments

data

data frame, at least with a column containing numeric water potential (bar), fresh.weight (g) and dry.weight (g) values, ordered by sample by descending water potential. A column containing the sample IDs is optionally required if several samples were measured.

sample

optional name of the column in data containing the sample IDs, default: "sample"

water.potential

optional name of the column in data containing the water potential values (bar), default = "water.potential"

fresh.weight

optional name of the column in data containing the fresh weight values (g), default: "fresh weight"

dry.weight

optional name of the column containing the dry weight values (g), default: "dry.weight"

Details

Above the turgor loss point, a linear relationship between water content and water potential exists. Based on this premise, saturated water content is found where water potential is zero. First, turgor loss point is calculated based on the relative leaf water loss (fresh weight minus dry weight relativized by the maximum leaf water content value). Then, data above the turgor loss point is extracted and fresh weight is fitted linearly to water potential. The point where water potential of the linear regression line is zero is the saturated water content.

Value

the original data frame (data) extended by a numeric column containing the saturated fresh weight values ("fresh.weight.saturated")

Examples

# get example data
df <- pressure_volume_data
# extend the data frame by saturated fresh weight
df <- FWSaturated(df)