DOI: 10.5061/dryad.0k6djhb51
title: Data from: Disentangling the relative contributions of factors determining seed physical defence: a global-scale data synthesis

description: Physical defence investment in seeds varies greatly among plant species
 and is associated with many potential factors. Exploring the factors
 explaining the interspecific variation in physical defence has long
 attracted particular attention in both ecology and evolution studies.
 However, the relative importance of the factors has not yet been
 quantitatively evaluated, which may lead to the misunderstanding of the
 main driver generating such interspecific variation. Here, by compiling a
 global database of the seed coat ratio (SCR), a proxy of seed physical
 defence, for 1,362 species, we provided the first quantification of the
 relative explanations of six factors that have been commonly considered to
 be associated with the interspecific variation in SCR: seed mass, seed
 desiccation response (desiccation-sensitive vs. desiccation-tolerant),
 seed dormancy (nondormant, physical dormant or other dormant types),
 growth form (herbaceous vs. woody), fruit type (dry vs. fleshy), and
 climate (19 bioclimatic variables representing temperature and
 precipitation). Using partial R2 calculation that can estimate
 the reduction in explained variance of a given factor after removing it
 from a full model containing all the other factors, we disentangled the
 relative contribution of each factor to explain variation in the SCR. Seed
 desiccation response was the most important factor associating with SCR
 variation, followed by seed dormancy, with a partial R2lik value
 of 9.70% and 1.41%, respectively. Plant growth form, seed mass, climate
 and fruit type showed little power to explain SCR variation, although they
 are often cited in the literature as potential factors. Our results
 highlight the important roles of seed desiccation response in shaping
 interspecific variation in the SCR. These findings provide a detailed
 interpretation of ecological patterns underlying the physical defence
 mechanisms and allocation strategies of plant seeds.
description: Data on the SCR and seed mass were collected from the
 literature published up until June 5, 2022. We used ((diaspore$ or “seed*
 coat$” or (seed$ and (kernel$ or reserve$)) or (seed$
 and “embryo*
 endosperm$”)) and (ratio$
 or proportion$ or fraction$ or tissue$ or percent* or weigh* or mass*)) or
 (seed$ and (defen* or protect*) and (physical* or mechanical*)) as search
 terms in the ISI Web of Science and further
 restricted our search to be consistent with the ‘Study Field Categories’
 of Wu et al. (2019), with the additional category ‘anatomy morphology’.
 Google Scholar was also searched with the same keywords to expand our
 dataset. Finally, 9,322 journal papers written in English
 were search out. We first screened all the papers based on the titles and
 abstracts and excluded 6,857 studies that were not relevant to our focused
 question. For the remaining 2,465 papers, we screened the full texts and
 finally yielded 85 papers containing available SCR data collected from 203
 sampling sites. The nomenclature of the species was checked against the
 World Flora Online database (WFO, v.2022.07; www.worldfloraonline.org)
 using the function ‘nameMatch’ in the R package ‘U.Taxonstand’ (Zhang
 & Qian, 2023), and 12 species were mismatched which were further
 checked against the Plants of the World Online (POWO,
 https://powo.science.kew.org/). In total, 1,758 records of the SCR were
 collected, comprising 1,362 species from 724 genera and 150
 families.
description: seed desiccation response  1 means desiccation-tolerant, 0 means
 desiccation-sensitive, blanks mean lack of information.
 growth form  1 means woody,
 and 0 means herbaceous. fruit
 type  1 means fleshy, 0 means dry, blanks
 mean lack of information. nondormant  1 means
 nondormant, 0 means dormant, blanks mean lack of information.
 physical dormant  1 means physical
 dormant, 0 means non physical dormant, blanks mean lack of
 information. other
 dormant  1 means other dormant (include
 physiological dormancy, morphological dormancy and morphophysiological
 dormancy), 0 means nondormant or physical dormant, blanks mean lack of
 information.
description: # Title of Dataset: --- Data from: Disentangling the relative
 contributions of factors determining seed physical defence: a global-scale
 data synthesis ## Description of the Data and file structure Dataset of
 SCR.xlsx Excel spreadsheet which includes species information, seed coat
 ratio, and factors that have been commonly considered as possible drivers
 of variation in the SCR: seed mass, seed desiccation response, growth
 form, fruit type, climate, and seed dormancy (nondormant, physical dormant
 or other dormant types).