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An allometry between seed kernel and seed coat shows greater investment in physical defense in small seeds
Author(s) -
Wu LaMei,
Chen SiChong,
Wang Bo
Publication year - 2019
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/ajb2.1252
Subject(s) - biology , coat , allometry , kernel (algebra) , investment (military) , botany , agronomy , ecology , mathematics , combinatorics , politics , political science , law
Premise of the Study Numerous studies have treated the mass of a whole seed as an integrated unit, although the components seed kernel and seed coat play different roles and are subject to different evolutionary selection pressures. In this study, we provided the first global‐scale quantification of the relative biomass investments in seed coats and seed kernels. We tested the following hypotheses: there is a negative allometry between seed kernel mass and seed coat mass, and therefore, seed coat ratio (SCR) is negatively correlated with seed mass. Methods We compiled a global‐scale data set from the published literature, including 680 plant species from 420 genera and 108 families. The relationships between seed components were quantified using standardized major axis regression, ordinary least squares regression, and phylogenetic independent analyses. Key Results We found a weak but significantly negative allometry between seed kernel mass and seed coat mass, which resulted in a negative relationship between seed mass and SCR . Similar results were found after accounting for the phylogeny. Conclusions The finding that smaller seeds invest more in protective tissues but less in stored reserves may explain the general prediction that larger seeds suffer greater predation than smaller seeds. Furthermore, this weak allometry may also explain, at least in part, why so many studies failed to identify a clear pattern of the effect of seed mass on many ecological processes. Our study suggests that the allometry between the two seed components must be considered when evaluating the ecological significance and evolutionary history of seed mass.