Classification and phylogenetic analysis of Chinese hawthorn assessed by plant and pollen morphology

Abstract

ABSTRACT. The Chinese hawthorn (Crataegus pinnatifida Bge. var. major N.E.Br.) is uniquely originated in northern China. The ecological and horticultural importance of Chinese hawthorn is considerable and some varieties are valued for their fruit or medicine extracts. Its taxonomy and phylogeny remain poorly understood. Apart from general plant morphological traits, pollen is an important trait for the classification of plants and their evolutionary origin. However, few studies have investigated the pollen of Chinese hawthorn. Here, an analysis of plant and pollen morphological characteristics was conducted in 57 cultivars from the Shenyang region. Thirty plant morphological characters and nine pollen grain characters were investigated. The plant morphological analysis revealed that the coefficient of variation for 13 traits was >20%, which indicates a high degree of variability. We also found that the pollen grains varied greatly in size, shape (from prolate to perprolate), and exine pattern (striate-perforate predominantly). The number of apertures was typically three. Based on these findings, we suggest that pollen morphology associated with plant morphological traits can be used for classification and phylogenetic analysis of Chinese hawthorn cultivars. In sum, our results provide new insights and constitute a scientific basis for future studies on the classification and evolution of Chinese hawthorn.

Food Applications and Potential Health Benefits of Hawthorn

“…In the 2020 edition of the Pharma-copoeia of the People’s Republic of China (Part I), hawthorn is a wrinkled, uneven, round piece sliced, and dried in autumn after the fruit has ripened [ 6 ]. Hawthorn is widely distributed in the world, with over 1000 species [ 7 ], mainly in the temperate regions of the Northern Hemisphere. C. monogyna and C. laevigata are the main hawthorn species in Central Europe, C. pentagyna , C. nigra , and C. azarolus are the hawthorn species of southern and southeastern Europe.…”

Molecular Analysis of Evolution and Origins of Cultivated Hawthorn (Crataegus spp.) and Related Species in China

“…Recent studies have examined intraspecific (Wu et al, 2008; Zhang et al, 2008; Sheng et al, 2017) and interspecific relationships (Su et al, 2015; Ma and Lu, 2016) of Chinese Crataegus . Previous investigations have used morphological data analyses and limited molecular data, but no study has explored the origin and evolution of cultivated Crataegus and related species that are native to China at the genomic level.…”

Crataegus bretschneideri (Rosaceae), a separate species endemic to northeast China

“…In this study, a total of 112 samples (Table 1) were collected, including four species of Malus as outgroups. The 108 Crataegus samples were selected from previous phylogenetic studies (Phipps 1990, Dai 2007, Lo et al 2009, Zarrei et al 2015, Erfani‐Moghadam 2016, Ma and Lu 2016, Emami 2018, Güney 2018, Du et al 2019) as representatives of Chinese Crataegus . All materials tested were identified based on recent floristic and taxonomic references, such as the treatment of Crataegus in the Flora of China (Gu and Spongberg 2003) and the China fruit plant monograph of hawthorn ( Crataegus ) flora (Zhao and Feng 1996).…”