FMSaturated {pvcurveanalysis}

Saturated fresh mass estimation

Description

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

Usage

FMSaturated(
  data,
  sample = "sample",
  water.potential = "water.potential",
  fresh.mass = "fresh.mass",
  dry.mass = "dry.mass"
)

Arguments

data

data frame, at least with a column containing numeric water potential (MPa), fresh.mass (g) and dry.mass (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 (MPa), default = "water.potential"

fresh.mass

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

dry.mass

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

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 mass minus dry mass relativized by the maximum leaf water content value). Then, data above the turgor loss point is extracted and fresh mass is fitted linearly to water potential. The point where water potential of the linear regression line is zero is the saturated water content.

Before using this function, check the data for an initial plateau. Data points in the initial part of the water potential versus RWD plot with a stronger then expected decline need to be omitted.

Value

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

Examples

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