Systematic palynology in Korean Piperales with special focus on its exine surface ornamentation and orbicule morphology

Abstract

The pollen and orbicule morphology of the Korean Piperales (Aristolochia, Asarum, Houttuynia, Piper, and Saururus) were investigated via scanning electron microscopy. Piperales pollen is a monad, its size ranging from very small to large (P = 7.78–51.4 μm, E = 6.68–43.1 μm), and having a mainly circular to sub-circular shape. The aperture type is constant in the genus [inaperturate (Aristolochia), tri to pentaporate (Asarum), and monosulcate (Houttuynia, Piper, and Saururus)]. There are four distinct types of exine ornamentation: Fossulate with perforate, microreticulate with gemmae, microperforate with granula, and microechinate. The orbicules (minute sporopollenin granules) were observed in all studied taxa and thus, may be a possible symplesiomorphic characteristic of Piperales. Further, the observed orbicule surface ornamentation was similar to pollen exine patterns, for example muri, gemmae, or granula. This resemblance between orbicule and pollen exine ornamentation may imply a similar biosynthesis pattern of sporopollenin of pollen exine and orbicules. The phenogram resulting from a cluster analysis using palynological characters was generally consistent with the known molecular phylogeny of Piperales. This initial study will help understand the palynological diversity and provide detailed information of pollen and orbicule characteristics in Piperales.

Comparative analysis of two Korean irises (Iris ruthenica and I. uniflora, Iridaceae) based on plastome sequencing and micromorphology

“…Orbicules, also known as Ubisch bodies, are small sporopollenin particles that can be produced on the inner locule walls of anthers 67 and that are, here, reported in I. ruthenica and I. uniflora for the first time. Even though orbicule morphology has been widely used to elucidate systematic and evolutionary relationships 12 , 68 , 69 , the occurrence of orbicules has, until now, only been reported in I. pallida Lam. 70 .…”

Floral micromorphological, palynological, and carpological characteristics of the rare endemic Korean species Peucedanum miroense (Apiaceae)

“…Given their potential taxonomic and phylogenetic significance, the presence of orbicules in different plant species and their morphological diversity have been the focus of a number of recent studies (Moon, 2018; Oak et al, 2022; Ruggiero & Bedini, 2020; Song et al, 2016; Song, Moon, et al, 2017; Song, Oak, et al, 2017). Although orbicule characteristics have been studied in different taxonomic groups, the presence of orbicules and their morphological diversity in Peucedanum has been verified in only two species, namely, P. alsaticum L. (Halbritter et al, 2021) and P. venetum Koch (Halbritter, 2019).…”

“…Given their potential taxonomic and phylogenetic significance, the presence of orbicules in different plant species and their morphological diversity have been the focus of a number of recent studies (Moon, 2018;Oak et al, 2022;Ruggiero & Bedini, 2020;Song et al, 2016;Song, Moon, et al, 2017;.…”

Scanning electron microscopic exploration of intricate pollen morphology and antimicrobial potentials of gourd family

“…Recent research has indicated that SEM offers a more comprehensive understanding of micromorphological characteristics. SEM can improve the visualization of ornamented pollen in micrographs, facilitating the explanation of pollen features for use in phylogenetic analysis (Oak et al, 2022).…”

“…Pollen grains are used to solve the taxonomic issues and to investigate whether climate change affects plants (Piotrowska-Weryszko et al, 2021). In plant systematics, the potential of morpho pollinic characters has always been a topic that has recently received attention.…”