Geometric morphometric analyses of leaf shapes in two sympatric Chinese oaks: Quercus dentata Thunberg and Quercus aliena Blume (Fagaceae)

Abstract

& Key message Geometric morphometric analyses (GMMs) of the leaf shape can distinguish two congeneric oak species Quercus dentata Thunberg and Quercus aliena Blume in sympatric areas. & Contexts High genetic and morphological variation in different Quercus species hinder efforts to distinguish them. In China, Q. dentata and Q. aliena are generally sympatrically distributed in warm temperate forests, and share some leaf morphological characteristics. & Aims The aim of this study was to use the morphometric methods to discriminate these sympatric Chinese oaks preliminarily identified from molecular markers. & Methods Three hundred sixty-seven trees of seven sympatric Q. dentata and Q. aliena populations were genetically assigned to one of the two species or hybrids using Bayesian clustering analysis based on nSSR. This grouping served as a priori classification of the trees. Shapes of 1835 leaves from the 367 trees were analyzed in terms of 13 characters (landmarks) by GMMs. Correlations between environmental and leaf morphology parameters were studied using linear regression analyses. & Results The two species were efficiently discriminated by the leaf morphology analyses (96.9 and 95.9% of sampled Q. aliena trees and Q. dentata trees were correctly identified), while putative hybrids between the two species were found to be morphologically intermediate. Moreover, we demonstrated that the leaf morphological variations of Q. aliena, Q. dentata, and their putative hybrids are correlated with environmental factors, possibly because the variation of leaf morphology is part of the response to different habitats and environmental disturbances. & Conclusion GMMs were able to correctly classify individuals from the two species preliminary identified as Q. dentata or Q. aliena by nSSR. The high degree of classification accuracy provided by this approach may be exploited to discriminate other problematic species and highlight its utility in plant ecology and evolution studies.

Population structure of Betula albosinensis and Betula platyphylla: evidence for hybridization and a cryptic lineage

“…A total of 382 mature leaves from 139 red birch individuals and 218 leaves from 74 white birch individuals were scanned using a Hewlett-Packard printer (LaserJet Pro MFP M128fn) with a resolution of 600 d.p.i. Thirteen landmarks were selected from each scanned leaf as described in previous studies (Jensen et al , 2002; Viscosi et al , 2009; Liu et al , 2018). These were: the distal tip of petiole (1), the junction between the petiole and the leaf blade (2), the first serration on the right-hand side of the leaf (3), the right-hand point of one-fifth of the leaf from the lower side (4), the right-hand point of the widest part of leaf (5), the right-hand point of three-fifths of the leaf from the lower side (6), the right-hand point of four-fifths of each leaf from the lower side (7), the leaf tip (8), the left-hand point of four-fifths of the leaf from the lower side (9), the left-hand point of three-fifths of the leaf from the lower side (10), the left-hand point of the widest part of the leaf (11), the left-hand point of one-fifth of the leaf from the lower side (12) and the first serration on the left-hand side of the leaf (13) (Supplementary Data, Fig.…”

In Vitro Propagation of Oriental White Oak Quercus aliena Blume

“…It is an important relict vegetation of temperate forests and culturally important sites. It is an instantly recognizable facet of Korean heritage [3], and an important forestry species in Northern China [4] commonly used as landscape trees [5]. Its wood is a good material for building boats, furniture and wood flooring for houses.…”

“…For example, Q. aliena and Q. dentata are sympatrically distributed in a wide range in warm temperate forests of East Asia. The two species overlap at flowering time, which facilitates the introgression and hybridization between the two species [4]. A chloroplast DNA polymorphism study in four oak species (Q. serrata, Q. mongolica var.…”

Morphometrical characteristics of cryptic invasive and indigenous gene pools of field maple Acer campestre L. in southern Sweden

“…For Quercus , Liu et al (2018) conducted a study with the aim to identify two sympatric species and their hybrid, preliminarily identified from molecular markers. The discrimination rate for the morphometrical data turned out to be 96.9 and 95.9% for respectively species.…”