No cell is an island: characterising the leaf epidermis using epidermalmorph, a new R package

CuticleTrace: A toolkit for capturing cell outlines from leaf cuticle with implications for paleoecology and paleoclimatology

Premise

Leaf epidermal cell morphology is closely tied to the evolutionary history of plants and their growth environments and is therefore of interest to many plant biologists. However, cell measurement can be time consuming and restrictive with current methods. CuticleTrace is a suite of Fiji and R-based functions that streamlines and automates the segmentation and measurement of epidermal pavement cells across a wide range of cell morphologies and image qualities.

Methods and Results

We evaluated CuticleTrace-generated measurements against those from alternate automated methods and expert and undergraduate hand tracings across a taxonomically diverse 50-image data set of variable image qualities. We observed ~93% statistical agreement between CuticleTrace and expert hand-traced measurements, outperforming alternate methods.

Conclusions

CuticleTrace is a broadly applicable, modular, and customizable tool that integrates data visualization and cell shape measurement with image segmentation, lowering the barrier to high-throughput studies of epidermal morphology by vastly decreasing the labor investment required to generate high-quality cell shape data sets.

The overlooked functions of trichomes: Water absorption and metal detoxication

Trichomes are epidermal outgrowths on plant shoots. Their roles in protecting plants against herbivores and in the biosynthesis of specialized metabolites have long been recognized. Recently, studies are increasingly showing that trichomes also play important roles in water absorption and metal detoxication, with these roles having important implications for ecology, the environment, and agriculture. However, these two functions of trichomes have been largely overlooked and much remains unknown. In this review, we show that the trichomes of 37 plant species belonging to 14 plant families are involved in water absorption, while the trichomes of 33 species from 13 families are capable of sequestering metals within their trichomes. The ability of trichomes to absorb water results from their decreased hydrophobicity compared to the remainder of the leaf surface as well as the presence of special structures for collecting and absorbing water. In contrast, the metal detoxication function of trichomes results not only from the good connection of their basal cells to the underlying vascular tissues, but also from the presence of metal-chelating ligands and transporters within the trichomes themselves. Knowledge gaps and critical future research questions regarding these two trichome functions are highlighted. This review improves our understanding on trichomes.