ABSTRACT
Although many fruit geometries resemble a solid of revolution, this assumption has rarely been rigorously examined. To test this assumption, 574 fruits of Canarium album (Lour.) DC. which appear to have an ellipsoidal shape, were examined to determine the validity of a general avian-based egg-shape equation, referred to as the explicit Preston equation (EPE). The assumption that the C. album fruit geometry is a solid of revolution is tested by applying the volume formula for a solid of revolution using the EPE. The goodness of fit of the EPE was assessed using the adjusted root-mean-square error (RMSEadj). The relationship between the observed volume (Vobs) of each fruit, as measured by water displacement in a graduated cylinder, and the predicted volumes (Vpre) based on the EPE was also evaluated using the equation Vpre = slope * Vobs. All the RMSEadj values were smaller than 0.05, which demonstrated the validity of the EPE based on C. album fruit profiles. The 95% confidence interval of the slope of Vpre vs. Vobs included 1.0, indicating that there was no significant difference between Vpre and Vobs. The data confirm that C. album fruits are solids of revolution. This study provides a new approach for calculating the volume and surface area of geometrically similar fruits, which can be extended to other species with similar fruit geometries to further explore the ontogeny and evolution of angiosperm reproductive organs.
Acknowledgments
We thank Dr Alexander Sukhorukov for handling this manuscript and thank two anonymous reviewers for their valuable and constructive comments.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Author contributions
Lin Wang: Formal Analysis (equal); Investigation (equal); writing-original draft (equal). Long Chen: Investigation (equal). Johan Gielis: Investigation (equal); review and editing (equal). Peijian Shi, and Karl J. Niklas: Formal Analysis (equal); Methodology (equal); review and editing (equal); supervision (equal).
Data availability statement
The raw data used in this study can be accessible on Dryad, a public repository (see Wang et al. Citation2023, https://doi.org/10.5061/dryad.2547d7wwz).