Digital morphometrics: Application of MorphoLeaf in shape visualization and species delimitation, using Cucurbitaceae leaves as a model

Abstract

PremisePlant leaves are one of the most important organs for plant identification due to their variability across different taxonomic groups. While traditional morphometrics has contributed tremendously to reducing the problems accompanying plant identification and morphology‐based species delimitation, image‐analysis digital solutions have made it easy to detect more characters to complement existing leaf data sets.MethodsHere, we apply MorphoLeaf to generate a morphometric data set from 140 leaf specimens of seven Cucurbitaceae species via landmark extraction, the reparameterization of leaf contours, and data quantification and normalization. A statistical analysis was performed on the resulting data set.ResultsA principal component analysis revealed that leaf blade area, blade perimeter, tooth area, tooth perimeter, the measure of the distance from tooth position to the tip, and the measure of the distance from tooth position to the base are important and informative landmarks that contribute to the variation within the species studied.DiscussionMorphoLeaf can be applied to quantitatively track leaf diversity, thereby functionally integrating morphometrics and shape visualization into the digital identification of plants. The success of digital morphometrics in leaf outline analyses presents researchers with opportunities to carry out more accurate image‐based research in areas such as plant development, evolution, and phenotyping.

Rasgos‐CL: A functional trait database of Chilean woody plants

“…Herbaria collections can be further mined for quantitative trait information via landmark extraction of digital images or reflectance spectra of pressed samples (e.g. Kothari et al, 2023; Oso & Jayeola, 2021). Beyond benefitting from our knowledge of Spanish, Rasgos‐CL also benefited from our local knowledge of local research institutions, which we contacted directly via our research networks to request data.…”

Morphological Characterization of Some Local Varieties of Fig (Ficus carica L.) Cultivated in Southern Italy

“…The size of the leaf is influenced by genetic and environmental factors (and their interaction) [36], such as temperature [40], soil fertility [41], water availability [42], and solar radiation [39]. Moreover, some size-related traits have been used to differentiate species and varieties [20,21,24,30]. Remarkably, the IPGRI fig descriptor list [8] recommends using LLL, LLW, CLL, PD, LLA, and PL to estimate leaf size.…”

“…Fig leaves, like many other plant species, show a symmetric pattern along the middle axis [30,31]. Structures (i.e., petiole, main vein, and central lobe length) positioned along this axis and landmark (LM 0, LM 1, LM 2) are defined as "unpaired", while all other are "paired" [32].…”