Theoretical Analyses of Turgor Pressure and Expansive Growth Rate of Plant Cells During Water Deficit

Abstract

Expansive plant growth during water deficit is common in temperate and extreme climates. Understanding how the turgor pressure, P, behaves during water deficit is essential for a better understanding of expansive growth rate, v. Here, validated biophysical equations together with dimensional analyses are used to simulate water deficit and determine the behavior of P and v. A dimensionless number, Πpw, helps simplify the biophysical equations and interpret the results. The magnitude of Πpw increases as water deficit severity increases. Analyses reveal that both P and v decrease curvilinearly as Πpw increases. Simple mathematical relationships between P, v, and Πpw, are derived, providing a clear and quantitative understanding of how P and v change as water deficits become more severe. Additionally, it is shown how the results of these analyses can be used to assess P and v of roots growing in water deficit.