Geometric and topological approaches to shape variation in Ginkgo leaves

Abstract

Leaf shape is a key plant trait that varies enormously. The range of applications for data on this trait requires frequent methodological development so that researchers have an up-to-date toolkit with which to quantify leaf shape. We generated a dataset of 468 leaves produced by Ginkgo biloba , and 24 fossil leaves produced by evolutionary relatives of extant Ginkgo . We quantified the shape of each leaf by developing a geometric method based on elastic curves and a topological method based on persistent homology. Our geometric method indicates that shape variation in modern leaves is dominated by leaf size, furrow depth and the angle of the two lobes at the leaf base that is also related to leaf width. Our topological method indicates that shape variation in modern leaves is dominated by leaf size and furrow depth. We have applied both methods to modern and fossil material: the methods are complementary, identifying similar primary patterns of variation, but also revealing different aspects of morphological variation. Our topological approach distinguishes long-shoot leaves from short-shoot leaves, both methods indicate that leaf shape influences or is at least related to leaf area, and both could be applied in palaeoclimatic and evolutionary studies of leaf shape.

Trait‐based approaches as ecological time machines: Developing tools for reconstructing long‐term variation in ecosystems

“…Given that leaves are primary sites of photosynthesis and play a central role in plant growth and survival, leaf fossils represent a potentially rich record of FTs through time. Leaf traits include morphological characteristics like shape and area (Hang et al, 2021), specific leaf area (Liu et al, 2019) and its inverse, leaf mass per area (LMA; Wright et al, 2004), chemical characteristics such as leaf nitrogen and phosphorus concentrations (Rawat et al, 2021), and physiological characteristics like vein (Blonder et al, 2014) and stomata (McElwain & Steinthorsdottir, 2017) density. Leaf traits have been widely studied in modern ecosystems and it has been shown that variation in some of these traits can reflect ecological trade‐offs and environmental factors (Blonder et al, 2014; Poorter et al, 2009; Wright et al, 2004).…”

TaSPL14-7A is a conserved regulator controlling plant architecture and yield traits in common wheat (Triticum aestivum L.)

“…Plant architecture is a key determinant of crop productivity and adaptability. It is a complex trait involving multiple factors, such as plant height, branching pattern, and leaf shape ( Wang et al., 2018 ; Hang et al., 2021 ). Common wheat ( Triticum aestivum L., AABBDD) is a major staple crop and an important human food source.…”