Plant Cuticles Exhibit Significant Mid-Infrared Emissivity in the Atmospheric Windows

TL;DR

Plant cuticles can emit heat in the mid-infrared range, helping plants manage solar radiation by dissipating energy through atmospheric windows.

Contribution

The study reveals that plant cuticles have significant mid-infrared emissivity linked to their molecular composition and structure.

Findings

Plant cuticles exhibit high mid-infrared emissivity matching atmospheric windows between 3–4 and 8–13 microns.

Optical properties of cuticles depend on molecular composition and arrangement, not just thickness.

Cuticles from different plant species show varied reflectance, transmittance, and absorbance in the MIR range.

Abstract

As sessile organisms, plants have developed strategies to cope with exposure to high radiation. The plant cuticle is located at the interface between the plant and the surrounding environment, thus acting as a first barrier that protects plants against environmental conditions, including solar radiation. The isolated cuticles displayed notable absorptance in the infrared spectral range which, according to Kirchhoff’s law of thermal radiation, equals the emission dissipation ability. Comparison among the different cuticles showed that a significant range of their reflectance, transmittance, and absorbance spectra match the spectral regions known as atmospheric windows, between 3–4 and 8–13 microns, located within the mid-infrared region (MIR). They allow energy to pass through into the outer space. These optical parameters varied between cuticles from different plant species and they were not a simple function of the cuticle’s thickness but the product of its specific composition in combination with its molecular arrangement.

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