Pollen analysis in some species of Linaceae-Linoideae from Argentina

Abstract

The pollen of Cliococca selaginoides (Lam.) C. M. Rogers & Mildner and eight Linum L. species from Argentina were examined using light and scanning electron microscopy. Both genera share pollen grains which are 3zonocolpate, isopolar, radiosymmetric, spheroidal and medium to large in size. The sculptural elements of the exine are gemmae or clavae, which allow the genera to be distinguished and the species to be characterised. In Cliococca Bad., the pollen is exclusively gemmate whereas in Linum the pollen is gemmate and clavate (except in L. catharticum L. whose pollen has only gemmae which are apically microechinate). The statistical analyses of quantitative and qualitative morphological characteristics were performed. A key to identify and distinguish the pollen types and subtypes is also provided. A generalized procrustes analysis (GPA) of joint characterisation based on both qualitative and quantitative characters identified four distinct groups.

Pollen morphology of endemic Linum species (Linoideae: Linaceae) from Mexico

“…On the other hand, the exine of all the studied species was semitectate, which differs from the description of Arreguín-Sánchez et al (1985) who reported it as intectate in L. mexicanum , L orizabae , and L. rzedowskii . It is worth remembering that the sexine layer forming a roof over the columellae, granules, or other infratectal elements, known as tectum, can partially fuse at the apex of ornamental elements in the 11 endemic taxa, as in other Linum species (Punt et al 2007; Lattar et al 2012) but was not detected by Arreguín-Sánchez et al (1985).…”

“…However, the multivariate statistical analyses defined the degree of importance of these traits in pollen variation, grouping those species that display narrow similarities in pollen morphology and identifying significant differences in three of the 11 species. The application of multivariate statistical analysis was not reported in previous studies on the pollen morphology of Linum (Saad 1961; Erdtman 1966; Xavier 1967; Ockendon 1971; Rogers and Xavier 1971; Rogers 1980, 1982, 1985; Chester and Raine 2001; Perveen and Qaiser 2008; Lattar et al 2012; Talebi et al 2012; Kluza-Wieloch et al 2015, 2018). Therefore, the present work is one of the first efforts to strengthen the conclusions derived from the study of the pollen morphological traits in Linum.…”

“…On the other hand, the exine of all the studied species was semitectate, which differs from the description of Arregu ın-S anchez et al (1985) who reported it as intectate in L. mexicanum, L orizabae, and L. rzedowskii. It is worth remembering that the sexine layer forming a roof over the columellae, granules, or other infratectal elements, known as tectum, can partially fuse at the apex of ornamental elements in the 11 endemic taxa, as in other Linum species (Punt et al 2007;Lattar et al 2012) but was not detected by Arregu ın-S anchez et al (1985). Exine thickness has been phylogenetically associated with a plesiomorphic (thin exine) or apomorphic (thick exine) character and is undoubtedly a valuable taxonomic tool for differentiating and grouping taxa (Xavier and Rogers 1963;Xavier et al 1980).…”

“…Although palynological work in Linum has been carried out since the 1950s worldwide (Saad 1961;Erdtman 1966;Xavier 1967;Ockendon 1971;Rogers and Xavier 1971;Rogers 1980Rogers , 1982Rogers , 1985Chester and Raine 2001;Perveen and Qaiser 2008;Lattar et al 2012;Talebi et al 2012;Kluza-Wieloch et al 2015, none of these publications includes a comprehensive report on pollen morphology, and there are no studies addressing all species of the genus. As a result, the characteristics of many species of the genus Linum, including the Mexican species, remain unknown.…”

“…Recently, several works have highlighted ornamental and structural aspects of pollen morphology as relevant taxonomic criteria for differentiating genera and species (Lattar et al 2012; Talebi et al 2014; Reshmi and Rajalakshmi 2019; Ragho 2020). Characters such as ripe pollen grain size, exine sculpturing, and number of apertures are of great utility, not only to clarify taxonomic issues but also to contribute to defining a phylogenetic signal (He et al 1995; Adedeji and Akinniyi 2015).…”