Dynamics of moisture diffusion and adsorption in plant cuticles including the role of cellulose

E. C. Tredenick,G. D. Farquhar

doi:10.1038/s41467-021-25225-y

Abstract

Food production must increase significantly to sustain a growing global population. Reducing plant water loss may help achieve this goal and is especially relevant in a time of climate change. The plant cuticle defends leaves against drought, and so understanding water movement through the cuticle could help future proof our crops and better understand native ecology. Here, via mathematical modelling, we identify mechanistic properties of water movement in cuticles. We model water sorption in astomatous isolated cuticles, utilising three separate pathways of cellulose, aqueous pores and lipophilic. The model compares well to data both over time and humidity gradients. Sensitivity analysis shows that the grouping of parameters influencing plant species variations has the largest effect on sorption, those influencing cellulose are very influential, and aqueous pores less so but still relevant. Cellulose plays a significant role in diffusion and adsorption in the cuticle and the cuticle surfaces.

Highlights

Food production must increase significantly to sustain a growing global population
Aqueous pores transport water and their properties vary between plant species, with Relative humidity (RH), and are less influenced by temperature and the presence of waxes than the lipophilic pathway[6,27]
Considering all the results from the sensitivity analysis, we find that cellulose and the aqueous pores contribute to mass increase of the cuticle in the shorter timescale (10 min), while the lipophilic pathway contributes to a small degree

Summary

Introduction

Food production must increase significantly to sustain a growing global population. Reducing plant water loss may help achieve this goal and is especially relevant in a time of climate change. 1234567890():,; Food production may need to increase by 70% in the 30 years, in order to feed the world’s estimated 9.7 billion people[1], and water loss from plants may hold one key, in a time of changing climate. The mechanisms of transport including adsorption and diffusion of water are, to date, poorly understood. & Enge, G., 2021, Materials on plant leaf surfaces are deliquescent in a variety of environments, unpublished), the water sorption capacity of cellulose[4] and aqueous pores[5,6]. Moisture sorption in plant cuticles is important to consider and can influence the formation of cracks, leading to issues with food production of fruits and mechanical properties of the plant cuticle[7,8]. Relative humidity (RH) has a large influence over the weight gain due to water sorption, and penetration of hydrophilic ionic agrochemicals, such as calcium chloride (CaCl2), across the cuticle[3,6,10], and so the degree of cuticle hydration is important

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