DOI: 10.5061/dryad.rv15dv4g5
title: Elucidating the association of trichome and stomatal densities across species

description: Previous studies suggested a trade-off between trichome density (Dt) and
 stomatal density (Ds) due to shared cell precursors. We clarified how,
 when, and why this developmental trade-off may be overcome across species.
 We derived equations to determine the developmental basis for Dt and Ds in
 trichome and stomatal indices (it and is), and the sizes of epidermal
 pavement cells (e), trichome bases (t) and stomata (s), and quantified the
 importance of these determinants of Dt and Ds for 78 California species.
 We compiled 17 previous studies of Dt-Ds relationships to determine the
 commonness of Dt-Ds associations. We modelled the consequences of
 different Dt-Ds associations for plant carbon balance. Our
 analyses showed that higher Dt was determined by higher it and lower e,
 and higher Ds by higher is and lower e. Across California species,
 positive Dt-Ds coordination arose due to it-is coordination and impacts of
 the variation in e. A Dt-Ds trade-off was found in only 30% of studies.
 Heuristic modeling showed that species sets would have the highest carbon
 balance with a positive or negative relationship or decoupling of Dt and
 Ds, depending on environmental conditions. Shared precursor cells
 of trichomes and stomata do not limit higher numbers of both cell types,
 or drive a general Dt-Ds trade-off across species. This developmental
 flexibility across diverse species enables different Dt-Ds associations
 according to environmental pressures. Developmental trait analysis can
 clarify how contrasting trait associations would arise within and across
 species.
description: # Elucidating the association of trichome and stomatal densities across
 species 
 [https://doi.org/10.5061/dryad.rv15dv4g5](https://doi.org/10.5061/dryad.rv15dv4g5) The data presented here are leaf trichome and stomatal traits measured for 78 California species from seven diverse California ecosystems, including alpine, chaparral, coastal sage scrub, desert, mixed conifer-broadleaf forest, mixed riparian woodland, and montane wet forest. Fully expanded, mature leaves were collected from each of the five individuals per species. Species average values were calculated from one leaf from each of three individuals per species. The traits presented are anatomical traits of the leaf epidermis, including cell sizes, densities, and indices. Additional details on field sampling and methodology can be found in a previous publication (Medeiros et al., 2023 *Functional Ecology*). Sampled leaves were fixed in FAA solution, and from these leaves, we quantified epidermal traits from leaf micrographs taken from nail varnish impressions of the abaxial and adaxial leaf surfaces. These nail varnish impressions were imaged with a light microscope at 40x objectivity and a camera with imaging software. The quantified traits include the areas of trichome, stomata (guard cell pair), and pavement cells, as well as trichome, stomata, and pavement cell densities. Traits were quantified using the software ImageJ. **Description of the data and file structure** In the data file, the first column is the species, and the following columns describe characteristics or trait values for that species, including the site the species were sampled, the site latitude and longitude, the vegetation type, the plant family to which the species belongs, the species growth form, the leaf trichome distribution, the leaf stomatal distribution, the leaf trichome morphology, if the measured trichomes were glandular/non-glandular, the specific surface measurements taken for that species, and the traits quantified. The traits quantified are designated by specific symbols, and a legend describing the symbols can be found to the right of the traits. Standard errors are also provided for the traits beneath the average trait values (rows 91-168). **Sharing/Access Information** Data are also provided in the original manuscript as Appendix S1.