Set of functions used to calculate tissue moisture from water potential and viceversa.

moisture_sapwoodWaterCapacity(Al2As, height, V, L, wd)

moisture_leafWaterCapacity(SLA, ld)

moisture_turgorLossPoint(pi0, epsilon)

moisture_symplasticRWC(psiSym, pi0, epsilon)

moisture_symplasticPsi(RWC, pi0, epsilon)

moisture_apoplasticRWC(psiApo, c, d)

moisture_apoplasticPsi(RWC, c, d)

moisture_tissueRWC(psiSym, pi0, epsilon, psiApo, c, d, af)

plant_water(x)

moisture_pressureVolumeCurvePlot(
  x,
  segment = "stem",
  fraction = "all",
  psiVec = seq(-0.1, -8, by = -0.01),
  speciesNames = FALSE
)

Arguments

Al2As

Leaf area to sapwood area (in m2·m-2).

height

Plant height (in cm).

V

Vector with the proportion [0-1] of fine roots within each soil layer.

L

Vector with the length of coarse roots (mm) for each soil layer.

wd

Wood density (g·cm-3).

SLA

Specific leaf area (mm2·mg-1).

ld

Leaf tissue density (g·cm-3).

pi0

Full turgor osmotic potential (MPa).

epsilon

Bulk modulus of elasticity (MPa).

psiSym, psiApo

Symplastic or apoplastic water potential (MPa).

RWC

Relative water content [0-1].

c, d

Parameters of the xylem vulnerability curve.

af

Apoplastic fraction (proportion) in the segment (e.g. leaf or stem).

x

An object of class spwbInput or growthInput.

segment

Segment whose relative water content curve to plot, either "stem" or "leaf" (the latter only available if transpirationMode = "Sperry" or transpirationMode = "Cochard").

fraction

Tissue fraction, either "symplastic", "apoplastic" or "all".

psiVec

Vector of water potential values to evaluate for the pressure-volume curve.

speciesNames

A flag to indicate the use of species names instead of cohort names in plots.

Value

Values returned for each function are:

  • moisture_symplasticRWC: Relative water content [0-1] of the symplastic fraction.

  • moisture_apoplasticRWC: Relative water content [0-1] of the apoplastic fraction.

  • moisture_symplasticWaterPotential: Water potential (in MPa) of the symplastic fraction.

  • moisture_apoplasticWaterPotential: Water potential (in MPa) of the apoplastic fraction.

  • moisture_turgorLossPoint: Water potential (in MPa) corresponding to turgor loss point.

  • moisture_segmentRWC: Segment relative water content [0-1].

  • water_plant: A vector of water content (mm) per plant cohort.

References

Bartlett, M.K., Scoffoni, C., Sack, L. 2012. The determinants of leaf turgor loss point and prediction of drought tolerance of species and biomes: a global meta-analysis. Ecology Letters 15: 393–405.

Hölttä, T., Cochard, H., Nikinmaa, E., Mencuccini, M. 2009. Capacitive effect of cavitation in xylem conduits: Results from a dynamic model. Plant, Cell and Environment 32: 10–21.

Martin-StPaul, N., Delzon, S., Cochard, H. 2017. Plant resistance to drought depends on timely stomatal closure. Ecology Letters 20: 1437–1447.

Author

Miquel De Cáceres Ainsa, CREAF

Examples

psi = seq(-10,0, by=0.1)
rwc_s = rep(NA, length(psi))
for(i in 1:length(psi)) rwc_s[i] = moisture_symplasticRWC(psi[i],-3,12)
plot(psi, rwc_s, type="l", xlab="Water potential (MPa)", ylab = "Symplasmic RWC")