Seed Micromorphology of Eleven Species of Pleione (Orchidaceae)

The micromorphological characteristics of the seeds of 11 species of Pleione have been studied, both qualitatively and quantitatively, to establish whether they are useful for systematic studies of the genus. The quantitative characteristics include seed length (0.237–0.626 μm), seed width (0.053–0.133 μm), seed length/width ratio (2.631–7.279), seed ridge thickness (1.4 E-3–4 E-3μm) and seed volume (1.88 E-4–3.06 E-3 μm3). The cluster analysis result agrees well with the results of previous systematic studies. The cluster analysis shows that: P. coronaria, P. forrestii and P. yunnanensis form a group, while the remaining eight species form a second group, with three subgroups, namely: P. limprichtii, P. pleionoides, P. formosana as group I; P. hookeriana and P. bulbocodioides as group II; and P. praecox, P. scopulorum and P. maculata for group III. All the Pleione species of Sect. Pleione and Sect. Humiles show the fusion of adjacent seed coat cells into a network. The shape of the seeds of P. praecox and P. maculata are very similar--being oval, and the mesh walls of their adjacent seed coat cells are not fused. Within these sections no clear pattern can be seen between the species, but the addition of further species might clarify the differences between Sect. Pleione and Sect. Humiles.

Seed Micromorphology, In Vitro Germination, and Early-Stage Seedling Morphological Traits of Cattleya purpurata (Lindl. & Paxton) Van den Berg

In the context of a symbiotic plant-fungus interaction study concerning Cattleya purpurata, we focused on some aspects of seed morphology and biology, and the early stages of seedling development. Seed morphology was characterized using light and scanning electron microscopy. In vitro seed germination capability was evaluated, comparing symbiotic and asymbiotic methods. The morphology of the seeds was overall comparable to that of other congeneric species, showing classical adaptations related to the aerodynamic properties and to the wettability of seeds, but calcium oxalate druses were identified inside the suspensor cells. Asymbiotic seed germination was successful in all tested media (17.1–46.5%) but was higher on 1/2 Murashige & Skoog. During symbiotic interaction with the fungal strain MUT4178 (Tulasnella calospora), germination rate was significantly lower than that obtained with the best three asymbiotic media, suggesting a low fungal compatibility. Seedling morphology was in line with other taxa from the same genus, showing typical characteristics of epiphytic species. Our observations, in particular, highlighted the presence of stomata with C-shaped guard cells in the leaves, rarely found in Cattleyas (where usually they are reniform), and confirm the presence of tilosomes in the roots. Idioblasts containing raphides were observed in both roots and leaves.

Seed micromorphology and anatomy of 36 Muscari (Asparagaceae) taxa from Turkey with notes on their systematic importance

This study presents the first in-depth evaluation of the morphological and anatomical characters, as well as their taxonomic importance, of the seeds of 36 taxa in subgenera Muscari, Leopoldia, Pseudomuscari and Botryanthus of the genus Muscari in Turkey, where 24 of the taxa are endemic. The results indicate that the taxa generally differ from each other in terms of seed shape and dimension. Seed dimensions vary between 1.66 mm and 3.21 mm in length, and between 1.12 mm and 2.63 mm in width. The seed surface ornamentation is grouped into nine forms: ruminate, reticulate, reticulate-areolate, reticulate-foveate, alveolate, scalariform, rugose, verrucate and areolate. The most common type is ruminate, while areolate, reticulate-foveate and scalariform ornamentation forms were found to be taxon-specific. Testa structures of the taxa examined consist in general of two different layers: the epidermis and the subepidermis in scleranchymatous or parenchymatous structures. The subepidermis may be absent in some of taxa. The structure and thickness of the epidermis and the subepidermis are very important characteristics that disclose interspecific relations among the examined taxa. We also provide a key for the identification of the studied taxa based on seed features.

Evaluation of seed morphology characteristics of Alnus taxa in Iran

Alnus Mill. is a problematic genus of Betulaceae, and there are several intrageneric classifications for the genus. Alnus species are widely distributed in the Hyrcanian forest of Iran, and different species with some intraspecific taxonomic ranks including subspecies and varieties have been reported from this country. We evaluate seed micromorphology characteristics of ten taxa using scanning electron microscopy and light microscopy in the current study. The data were analyzed using SPSS and MVSP software. Results revealed that qualitative characteristics such as seed shape, surface sculpturing pattern, presence of indumentum, and its type vary among the studied taxa and have diagnostic value. However, seed color was nearly stable among the taxa. Besides, quantitative variables highly differed among the taxa. In the UPGMA tree, Alnus taxa were clustered into three groups, and these groups were supported by PCA and PCO plots. According to the PCA bi-plot, some taxa were characterized by the particular characteristic(s) that was useful for their identification. In some cases taxa clustering was similar to those of previous phylogenetic and morphological studies. Our findings revealed that seed morphology characteristics are a valuable taxonomical tool in identifying most Alnus taxa, except for A. glutinosa subspecies, which have similar seed morphology features in common.

Micromorphology of seeds of three Mexican species of Pinguicula (Lentibulariaceae) show autofluorescence using confocal laser scanning microscopy

Pinguicula (Lentibulariaceae) includes around 110 described species, 51 of which are distributed in Mexico. Recently, P. casperi was described and its authors observed that it has intermediate morphological characters between P. oblongiloba and P. parvifolia, its putative parents. The micromorphological study of seeds has previously defined the identity of some species, and this can provide evidence of hybridization. The objectives of the present study were 1) to describe the seed micromorphology of P. casperi, P. oblongiloba and P. parvifolia and 2) to provide an economical, easy, and practical method for observing seed micromorphology using confocal laser scanning microscopy (CLSM). Seed micromorphology was considerably different between P. casperi, P. oblongiloba, and P. parvifolia. Therefore, no evidence of hybridization was found. The seeds of the three species were autofluorescent. The process of obtaining the images of the seeds with CLSM was harmless, low cost, and practical. Additionally, the images obtained were high quality and had a high resolution, making it possible to observe and compare the microstructures on the seed surfaces. CLSM is a useful, practical alternative for future taxonomic studies of the genus Pinguicula.

Fruit and seed micromorphology of the genus Iberis L. (Brassicaceae) in Turkey and its utility in taxonomic delimitation

Background: This paper investigates whether the fruit and seed micromorphology of eight Turkish Iberis (Brassicaceae) species can be used as a further aid in their taxonomic delimitation. Questions: Are the micro-morphological characters of the fruits and seeds of Iberis useful to support the taxonomic delimitation of its species? Studied species / data description /Mathematical model: The eight species of Iberis present in Turkey were examined. The fruit and seed characteristics were obtained and statistical analysis was performed using UPGMA. Study site and dates: Fifteen localities in Turkey, from 2015 to 2019. Methods: Samples of fruit and seed of eight species of Iberis were collected, stored, and later measured and described with aid of light and scanning electron microscopies. Results: All eight species had different fruit and seed characters; particularly differing from each other with respect to fruit and seed size, seed shape and seed ornamentation. Two fruit ornamentation types were evident, smooth and striated. The seed coat surface were separated into three types: reticulate, reticulate-rugose and reticulate-papillate, being reticulate the most common. Further differences were noted for the seed surface epidermal structures, notably species had rectangular, tetragonal, or pentagonal patterning. An identification key was constructed based on a similarity analysis. Conclusions: Fruit morphology, seed dimensions, colour, and epidermal cell patterning are useful microcharacters that enabled species-level determinations in the Iberis species sampled.

Seed micromorphology of representatives of holoparasitic Orobanchaceae genera from the Caucasus region and its taxonomic significance

Obligate parasitic plant species from the Orobanchaceae family belong to the most critical genera of world flora. Due to their strongly reduced vegetative organ architecture, there arise many difficulties and mistakes in species identification, and extra characteristics of systematic importance are required. Seed micromorphology is a highly informative taxonomic criterion that helps to resolve ambiguities in plant taxonomy and evolution, and has proved to be a valuable complementary tool for Orobanchaceae species identification. In this study, seeds of 43 holoparasitic species from the Cistanche, Diphelypaea, Orobanche and Phelipanche genera collected in the Caucasus were subjected to micromorphological analysis. The Caucasus is one of the most important centres of world biodiversity, with many endangered and endemic parasitic plants. Twenty two quantitative/qualitative micromorphological seed parameters were analysed using stereo ZOOM, confocal scanning laser (CLSM) and scanning electron (SEM) microscopy. Three types of seed were established based on periclinal wall ornamentation: 1) clearly pitted sculpturing in all Cistanche, Diphelypaea, and most Orobanche seeds; 2) fibrillar and veined sculpturing in Phelipanche seeds; and 3) smooth, granular or rugged (very rarely visibly pitted) outer periclinal wall in O. coerulescens and O. colorata seeds. However, CLSM, used in present studies for Orobanchaceae seeds for the first time, revealed more details of wall lignification and ornamentation invisible in SEM images. The best micromorphological characteristics for species identification are the type of ornamentation of the periclinal wall, the width of anticlinal wall, the character of perforation, perforation length and width, the fibrillar character, and fibrillar and vein width. A comparison of the main characteristics distinguishing the seeds of Orobanchaceae is also presented and discussed.