Physico-chemical properties of plant cuticles and their functional and ecological significance

Abstract

Most aerial plant surfaces are covered with a lipid-rich cuticle, which is a barrier for the bidirectional transport of substances between the plant and the surrounding environment. This review article provides an overview of the significance of the leaf cuticle as a barrier for the deposition and absorption of water and electrolytes. After providing insights into the physico-chemical properties of plant surfaces, the mechanisms of foliar absorption are revised with special emphasis on solutes. Due to the limited information and relative importance of the leaf cuticle of herbaceous and deciduous cultivated plants, an overview of the studies developed with Alpine conifers and treeline species is provided. The significance of foliar water uptake as a phenomenon of ecophysiological relevance in many areas of the world is also highlighted. Given the observed variability in structure and composition among, for example, plant species and organs, it is concluded that it is currently not possible to establish general permeability and wettability models that are valid for predicting liquid-surface interactions and the subsequent transport of water and electrolytes across plant surfaces.

The permeation barrier of plant cuticles: uptake of active ingredients is limited by very long‐chain aliphatic rather than cyclic wax compounds

“…The lipophilic pathway is thought to lead across deposits of waxes like VLCAs, whereas the polar pathway has been associated with hydrated functional groups in the cuticular network leading to an aqueous continuum. Among others, this might be water‐filled polysaccharide strains extending from the epidermal cell wall partially to the outer surface of the cuticle . The lipophilic pathway is depicted as waxes consisting of crystalline and amorphous fractions .…”

Variability in leaf wettability and surface water retention of main species in semiarid Loess Plateau of China

“…Leaf adaxial surfaces were more wettable than abaxial surfaces after comparing pooled data from all species. Leaf wetting is beneficial to plant growth due to potential absorption of water (Fernández et al, 2017;Goldsmith et al, 2016); however, it can be harmful by greatly reducing the photosynthetic rate or promoting pathogen infection, pollutant deposition, and foliar nutrient leaching (Aryal & Neuner, 2010;Ishibashi & Terashima, 1995). Typically, the abaxial surface was less wettable and had higher stomatal density than adaxial surface (Brewer & Nunez, 2007;Pandey & Nagar, 2003;Smith & McClean, 1989).…”

“…Most aerial plant organs are covered with a cuticle consisting of a cutin matrix with cuticular waxes embedded in and deposited on the surface of the matrix (Fernández et al, 2016;Fernández et al, 2017). Most aerial plant organs are covered with a cuticle consisting of a cutin matrix with cuticular waxes embedded in and deposited on the surface of the matrix (Fernández et al, 2016;Fernández et al, 2017).…”

“…Leaf wettability, adhesion or repulsion of water drops, is an important plant functional trait and varies greatly among species and communities (Brewer & Nunez, 2007;Fernández et al, 2017;Holder, 2007).…”

The importance of phyllosphere on plant functional ecology: a phyllo trait manifesto

“…However, it is not known how the interplay between the phyllosphere and plant traits may directly affect axes related to carbon acquisition. In terms of plant hydraulics, fungal endophytes and bacteria might have an important role in facilitating foliar water uptake (FWU) through stomata since they decrease leaf surface tension and/or act as a direct entry pathway for water, in the case of fungal hyphae growing into stomata pores (Burgess & Dawson, ; Burkhardt, ; Fernández et al ., ). FWU has been indicated as an important ecophysiological process alleviating water stress and allowing plant growth and survival under drought conditions (Burgess & Dawson, ; Eller et al ., ; Fernández et al ., ).…”