Testa Cells Research Articles

Micromorphological study of some Salsola species (Amaranthaceae) in Iran and its systematic significance using scanning electron microscopy.

Using scanning electron microscopy (SEM), six Salsola species from Iran were examined for their epidermis, seed, and fruit micromorphology. Among them were S. brachiata from section Heterotricha, S dendroides, S. incanescens, and S. orientalis from section Caroxylon, S. kali from section Kali, and S. turcomanica from section Physurus. Epidermal cells are divided into three types. There were diamond, irregular, and polygonal cells, as well as straight and undulated walls. Studied species of Salsola have smooth or sculptured fruit surfaces, and there are three main types of fruit surface ornamentation. There is a significant difference between these species based on the type of hair and density of the fruit. Seed shape and color have little systematic significance. The seed epidermis is composed of polygonal, elongated polygonal, irregular, and diamond cells. Although polygonal and irregular testa cells are most common, their size and shape can provide additional information and useful diagnostic characteristics at both specific and infraspecific levels. For taxonomic separation, the current study provides novel insights at micromorphological levels. RESEARCH HIGHLIGHTS: This article reports halophyte are shown as models for adaptation to extreme habitats. These plants are placed among the ecological communities of xerophytes. Here, for the first time, the microstructural analysis of Salsola has been investigated. Additionally, it provides new insights into plant species' response to extreme conditions, as well as possible adaptation strategies at the micromorphological level.

Sphaerocrystals in seeds of Euphorbia subgenus Esula (Euphorbiaceae): morphology, occurrence, and relationship with phylogeny

Abstract The term ‘sphaerocrystals’ (also sphaerites) in classic plant morphology was usually applied to spherical bodies visible in polarized light with a characteristic ‘Maltese cross’ and consisting of both inorganic and organic compounds. Initially sphaerocrystals were found in algal cells but were later also discovered in various organs of vascular plants (including seeds). Several authors noticed spherical particles on the seed surface and in testa cells of some Euphorbia species but a comprehensive study of this character in the genus (including the morphological origin of such particles) has not been carried out. We studied 72 species belonging to all 21 sections of Euphorbia subgenus Esula for presence of spherical particles on seed surface and in the testa using scanning, transmission, confocal laser electron microscopy, and light microscopy; histochemical and element analyses were also involved. We found that these particles have the same morphological features (including the demonstration of ‘Maltese cross’ in polarized light) as the ‘classic’ sphaerocrystals. We have recorded sphaerocrystals in 53 sampled species belonging to 20 sections of Euphorbia subgenus Esula; they are localized mostly in mesotesta cells and in some species are exuded onto the seed surface where they are often aggregated into clusters. Sphaerocrystals were absent in the sampled species (with one exception) of one of the major clades of the subgenus, formed by E. sect. Helioscopia and E. sect. Holophyllum. The absence of sphaerocrystals in this early divergent lineage of E. subgen. Esula may be related with adaptation of species of this lineage to more mesic habitats.

Evolution of seed characters and of dispersal modes in Aizoaceae.

The family Aizoaceae includes ~1880 species and is one of the more diverse groups within Caryophyllales, particularly in arid areas in the western part of southern Africa. Most species are dwarf succulent-leaf shrubs. In response to the harsh climatic conditions prevalent where they occur, many representatives have evolved special reproductive adaptations. These include hygrochastic capsules (mostly found in Mesembryanthemoideae and Ruschioideae), burr-like indehiscent and one-seeded, winged diaspores, and fast germination of seeds after rain. We focused on anatomical features, evolutionary trends, and the ecological significance of various morpho-anatomical structures found in the seeds. The seeds of 132 species from 61 genera were studied, and 18 diagnostic characters were discovered. All studied characters were compared with those of other families from core Caryophyllales. The seed notch and embryo shape were added to the list of characteristics distinguishing major clades within the family. In addition, the presence of longitudinal ridges and a keel on the seed are additional characters of Aizooideae and combined Ruschioideae-Apatesieae, respectively. Puzzle-like borders of testa cells are a common trait in Ruschioideae and Mesembryanthemoideae. Most taxa in Aizoaceae have a thin seed coat, which is the ancestral state within the family. This may facilitate fast germination. We observed several shifts to a medium-thick or thick seed coat in members of Ruschioideae and Acrosanthoideae. These inhabit fire-prone environments (in vegetation types known as fynbos and renosterveld), where the thickened seed coat may protect against damage by fire. Multi-seeded fruits are the ancestral state within Aizoaceae, with several shifts to one-(two-)seeded xerochastic fruits. The latter are dispersed via autochory, zoochory, or anemochory. This trait has evolved mainly in less succulent subfamilies Acrosanthoideae, Aizooideae, and Sesuvioideae. In highly succulent subfamilies Ruschioideae and Mesembryanthemoideae, fruits are almost exclusively multi-seeded and hygrochastic with ombrohydrochoric dispersal. A reduction in the number of seeds within a dispersal unit is rare. Within Apatesieae and Ruschieae, there are also a few unusual genera whose fruits fall apart into one- to two-seeded mericarps (that are mainly dispersed by wind).

Numerical analyses of seed morphology and its taxonomic significance in the genus Oxytropis DC. (Fabaceae) from northwestern China.

The lack of diagnostic taxonomic characteristics in some species complexes leave the species delimitation of Oxytropis DC. unresolved. Seed morphological features have proved to be useful diagnostic and taxonomic characteristics in Fabaceae. However, there are few systematic studies on the seed characteristics of Oxytropis. Here, we used scanning electron and stereoscopic microscopy to investigate the seed characteristics of 35 samples obtained from 21 Oxytropis species from northwest China. Our examination showed two main types of hilum positions, terminal and central, and five different types of seed shapes: prolonged semielliptic, reniform, prolonged reniform, quadratic, and cardiform. Seven different sculpturing patterns were identified: scaled, regulated, lophate with stellated testa cells, simple reticulate, rough, compound reticulate, and lophate with rounded testa cells. The seeds ranged from 1.27 to 2.57 mm in length and from 1.18 to 2.02 mm in width, and the length-to-width ratio ranged from 0.89 to 1.55 mm. The seed shape was constant within species and was useful for species delimitation within the genus Oxytropis when combined with other macroscopic traits. In contrast, the sculpturing patterns were highly variable at the species level and could not be used for species identification. Results of the cluster analysis and principal component analysis (PCA) indicated that the seed traits of Oxytropis species are useful for taxa identification at the species level, but have low taxonomic value at the section level.

Seed Morphology, Life Form and Distribution in Three Bromheadia Species (Epidendroideae, Orchidaceae)

The seed morphology of three species belonging to the genus Bromheadia was analyzed under light and scanning electron microscopy. The seeds of B. cecieliae and B. truncata were studied for the first time. Differences in the qualitative and quantitative characteristics between the terrestrial B. finlaysoniana and the epiphytes B. cecieliae and B. truncata were observed, which were in concordance with the life form. Due to the variability of the seed shapes, a new methodology is proposed to analyze the distance between the embryo and the testa cells, with the aim of demonstrating the presence of air space within the seed. The method is compared to previous formulae used to measure free air space. Furthermore, a new measurement, the angle in twisted testa cells of epiphytic orchids, is proposed, to evaluate the degree of torsion in medial cells. Although the wide distribution of B. finlaysoniana could be related to the great buoyancy of their seeds in contrast to the limited distribution of B. cecieliae, we consider that environmental factors are more influential than the buoyancy of seeds when understanding the distribution of these taxa. Future studies on seeds morphology in orchid genera with terrestrial and epiphytic taxa will provide new insights into this research.

Differences in seed morphometrics of representative orchids native to North America and Hawaii using scanning electron microscopy

Ultrastructure and dimensions of whole seed, embryo, and testa cells of 10 orchid species native to North America and Hawaii are reported. Seeds of seven terrestrials (Cleistes bifaria, Isotria medeoloides, Liparis elata, L. hawaiensis, Platanthera holochila, P. integrilabia, and P. leucophaea), two epiphytes (Encyclia tampensis, Epidendrum nocturnum), and one semi-aquatic (Habenaria repens) orchid were studied by light and scanning electron microscopy. In contrast to the epiphytes and the semi-aquatic orchid, seeds of terrestrial species were larger in size evidenced by a small length/width ratio, had greater seed volume, a larger number of testa cells, and embryos with the highest mean area, supporting the existing literature. Interestingly, seeds of both Hawaiian species differed noticeably from their mainland counterparts (L. hawaiensis vs. L. elata; P. holochila vs. P. integrilabia and P. leucophaea). Our study lends support for differences between genera, but also within at least two genera (Liparis, Platanthera), for orchids occupying different habitats separated by thousands of km (Hawaii, Florida). For orchids threatened with immediate extinction in North America and worldwide, a better understanding of seed morphometrics, and especially the structure and function of the testa, may be useful in developing more effective protocols aimed at in vitro seed germination.

Seed morphology of some Plantago (Plantaginaceae) species in Iran and its systematic and phylogenetic implications

Plantago is a cosmopolitan genus with approximately 200 species and various infrageneric classifications have been reported. In this study, the seed morphologies of 19 species of Plantago from Iran were studied and documented in detail using scanning electron microscopy and light microscopy. The studied species were grouped by using statistical analyses such as a minimum spherical cluster method based on Euclidean distance, principal coordinate analysis, and multidimentional scaling. We have described four types based on the seed shape and states of the inner side of the studied seeds: convex- angular type, convex-elliptic type, flat-elliptic type, and concave-elliptic type. In this study, three types of seed coat patterns were recognized: reticulate, scalariform to reticulate, and papillate. Regardless of the limited range taxa considered, our data convincingly support a close relationship between subgenera Plantago and Coronopus, and between Albicans and Psyllium. Consequently, we would suggest that the species of subgenus Coronopus should be placed within subgenus Plantago as Pilger's taxonomy, and the species of subgenus Albicans should be merged within subgenus Psyllium as Rønsted et al.'s taxonomy. The seed morphology revealed that subgenus Plantago and subgenus Albicans are paraphyletic. Moreover, the deformation of testa cells can be an indicator for finding different lineages at series to the subgenus level. The features of the arrangement of testa cells and anticlinal walls can be used at the species level, especially when the morphological diversity between species is low. We conclude that seed morphology provides useful and important information on phylogenetic relationships of Plantago species, and thus they have systematic significance.

Taxonomic significance of seed and leaf micromorphology in Saponaria (Caryophyllaceae)

The seed and leaf structures of some species belonging to the genus Saponaria (Caryophyllaceae) were examined using SEM. These species were: S. calabrica, S. dalmasii (endemic), S. glutinosa, S. halophila (endemic), S. karapinarensis (endemic), S. kotschyi (endemic), S. mesogitana, S. officinalis, S. orientalis, S. pamphylica (endemic), S. picta (endemic), S. pinetorum var. elatior (endemic), S. prostrata subsp. anatolica (endemic), S. prostrata subsp. calvertii, S. prostrata subsp. prostrata (endemic), S. pumilio, and S. tridentata. The results obtained show that the micromorphology of the seed are useful to distinguish the studied species. Four groups can be distinguished using the number of seed per capsule. In addition, the shape of the seed, microsculpture, shape and margin of testa cells were found as important characteristics to identify the various species. Leaf anatomy reveals that trichome type and mesophyll symmetry define significant differences between the studied species.

Structure of the seed coat of the species of Asteraceae. II (tribe Heliantheae)

We present the study of the structure of the seed coat of 52 species from 31 genera (Acmella, Ambrosia, Aspilia, Balsamorhiza, Blainvillea, Borrichia, Chrysogonum, Clibadium, Delilia, Echinacea, Eclipta, Engelmannia, Helianthella, Helianthus, Heliomeris, Heliopsis, Iva, Lindheimera, Parthenium, Ratibida, Rudbeckia, Sanvitalia, Silphium, Sphagneticola, Synedrella, Synedrellopsis, Tithonia, Verbesina, Xanthium, Zaluzania, Zinnia) of ten subtribes of the tribe Heliantheae of the Asteraceae family. The study of the seed coat structure was carried out by scanning electron microscopy. It has been established that the species of the tribe have a distinctly sculptured or smooth, well-developed testa, which remains until the full maturity of the achenes. The sculpture of the seed surface in most species is determined by the exotesta cells. The several types and subtypes of the structure of exotesta cells due to the degree and type thickening of cell walls were revealed. The sculpture of the surface of the seeds of the species that make up the tribe is diverse. The shape and specifications of the thickening of the walls of the exotesta cells within the genus and subtribe are diverse, as a result, it is not possible to identify the characters inherent in the entire Heliantheae tribe, as well as its subtribes and genera. The division of the Heliantheae tribe into subtribes is not supported by the results of our study. The conservative nature of the characters of the testa cells structure allows to use them in solving problems of taxonomy of genera, phylogenetics, to establish the degree of homogeneity of taxa united in genera and subtribes of the Heliantheae tribe.

Seed macro- and micromorphology in Allium (Amaryllidaceae) and its phylogenetic significance.

Macro- and micromorphology of seeds are diagnostic characteristics of importance in delimiting taxa in Allium (Amaryllidaceae). However, there is no consensus on the phylogenetic significance of testa cell characteristics and whether they reflect the different evolutionary levels recognized in Allium. Seeds of 95 species (98 samples) representing 14 subgenera and 58 sections of Allium were examined using scanning electron microscopy (SEM) for such traits as periclinal wall surface area of ten testa cells, distance between testa cells (macromorphology), testa cell shapes, and arrangement and structure of anticlinal and periclinal walls (micromorphology). The data matrix was subjected to cladistic analysis. The produced phylogenetic tree was examined against the molecular tree obtained from publically available ITS sequences. The periclinal wall surface area of ten testa cells and the distance between them, examined for the first time, were found useful for delimitation of species in Allium. Based on seed macro- and micromorphology, we present a taxonomic key and a hypothetical reconstruction of the migration routes during the early stages of evolution of Allium. The ancestors of Allium originated in an area bounded by the Caucasus, Central Asia and Iran. The seed testa morphology-based evolutionary state of a species is determined by two parameters: the shape of the periclinal walls and curvature of the anticlinal walls.

Phylogenetic relationships in Coryphantha and implications on Pelecyphora and Escobaria (Cacteae, Cactoideae, Cactaceae).

The genus Coryphantha includes plants with globose to cylindrical stems bearing furrowed tubercles, flowers arising at the apex, and seeds with flattened testa cells. Coryphantha is the second richest genus in the tribe Cacteae. Nevertheless, the genus lacks a phylogenetic framework. The limits of Coryphantha with its sister genus Escobaria and the infrageneric classification of Coryphantha have not been evaluated in a phylogenetic study. In this study we analyzed five chloroplast regions (matK, rbcL, psbA-trnH, rpl16, and trnL-F) using Bayesian phylogenetic analysis. We included 44 species of Coryphantha and 43 additional species of the tribe Cacteae. Our results support the monophyly of Coryphantha by excluding C.macromeris. Escobaria + Pelecyphora + C.macromeris are corroborated as the sister group of Coryphantha. Within Coryphantha our phylogenetic analyses recovered two main clades containing seven subclades, and we propose to recognize those as two subgenera and seven sections, respectively. Also, a new delimitation of Pelecyphora including C.macromeris and all species previously included in Escobaria is proposed. To accommodate this new delimitation 25 new combinations are proposed. The seven subclades recovered within Coryphantha are morphologically and geographically congruent, and partially agree with the traditional classification of this genus.

A seed morphometry study of selected species of Bulbophyllum and Dendrobium (Orchidaceae) in relation to their dispersals

Abstract. Aprilianti P, Handini E, Puspitaningtyas DM. 2021. A seed morphometry study of selected species of Bulbophyllum and Dendrobium (Orchidaceae) in relation to their dispersals. Biodiversitas 22: 5564-5571. Bulbophyllum and Dendrobium are the two largest genera of Orchidaceae. The seed morphometry studies of Bulbophyllum and Dendrobium, mainly from Southeast Asia are still poorly reported. The research aimed to characterize seeds micromorphometry of selected species of Bulbophyllum and Dendrobium, namely Bulbophyllum graveolens, B. macranthum, B. phalaenopsis, Dendrobium bicaudatum, and D. bifalce in relation to their dispersal mechanisms. Twenty seeds of each species were studied using light and scanning electron microscope (SEM). Qualitative characters, such as seed shape, testa cell shape, wall structure, and its orientation and quantitative data, such as seed and embryo were analyzed. The results showed that the shape of the seeds of all the species was fusiform. The testa cell walls were smooth and covered by waxes. The anticlinal walls were raised and thickened. Bulbophyllum and Dendrobium can be differentiated in the orientation of testa cells, which is spirally oriented in Bulbophyllum and parallel to the long axis in the Dendrobium. There are no large variations in seed and embryo volume as well as seed air space (SAS) in different taxa. The SAS value can be used to predict the dispersal mechanism and distribution area of the orchid species. Unfortunately, the SAS values are not always positively correlated with the distribution area and other factors inhibit the spread of the species.

Seed morphology: An addition to the taxonomy of Astragaleae and Trifolieae (Leguminosae: Papilionoidae) from Pakistan.

Seed morphology was described in detail for 12 species belonging to 5 genera of tribes Astragaleae and Trifolieae (Leguminosae; Papilionoideae) using scanning electron microscopy (SEM) to evaluate the taxonomic relevance of macromorphological and micromorphological seed characters. The study aims to search for diagnostic seed ultrastructural features that may help to elucidate species identification. For SEM analysis, seed morphological characters including seed form and shape, color and size, ornamentation, epidermal cell shape, and anticlinal wall pattern were investigated. As a result of the study, species-specific characters have been determined. Based on seed exomorphology, three characteristic cell patterns; irregular, round, and flat were observed. In majority of studied taxa, species may be further differentiated based on seed shape, size, and surface ornamentation. The inconsistency in testa cell pattern, shape, and distribution of papillae or protuberances may probably give further insight and significant morphological features at specific and generic level within the tribe. This study illustrated that considerable taxonomic knowledge can be obtained by examining the seed characters of Astragaleae and Trifolieae, particularly at the species level. The results demonstrated that the use of SEM in seed morphology could play a role in the identification of taxa particularly at genus and species level. Twelve species of Astragaleae and Trifolieae were studied in order to describe and investigate the seed morphology and to evaluate the diagnostic value of this character using a SEM. A broader taxon sampling is required for classification at generic and tribal level, besides molecular and phylogenetic studies.

Seed morphology and testa ultrastructure in Alliumstipitatum complex (Amaryllidaceae; Allioideae) and their systematic significance

Characteristic features of seed and testa cells in 13 species of Allium, representing its five recognized sections, Compactoprason, Megaloprason, Procerallium, Decipientia and Pseudoprason were studied using both stereomicroscope and scanning electron microscope. The identified characters, such as seed shape, alignment and shape of testa cells, features of outer cell walls, verruca type, density of verrucae and granules, seed size as well as cell wall undulations were evaluated statistically. The our findings indicated the significance level of P ? 0.01 for examined characters using the Kruskal-Wallis and ANOVA analyses.Two principal components of factor analysis revealed the following traits to be most important in distinguishing taxa at various taxonomic ranks within the complex (sections, subsections and species), based on 50.94% of total variance and a correlation coefficient of 0.93: shape and sculpturing of periclinal walls, undulation details of anticlinal walls, verruca type, testa cell alignment, and size of seed and testa cells. The general pattern of testa shared by all taxa of studied complex included convex periclinal walls with verrucate surface and undulated anticlinal walls from S- to U-like, but some taxa differed from each other in the details of testa sculpturing. Exceptionally, the monotypic section, Decipientia revealed adifferent pattern, showing smooth seed surface composed of polygonal testa cells with tightarrangement, flat periclinal surfacebearingsulcate verrucae, and straight anticlinal walls.

Seed Morphology of Allium L. (Amaryllidaceae) from Central Asian Countries and Its Taxonomic Implications.

We studied seed macro- and micro-morphological characteristics of 48 Allium species (51 accessions) belonging to 24 sections and 7 subgenera. Our taxonomic sampling focused on the central Asian regions of Uzbekistan, Kyrgyzstan, and Mongolia. The seed length ranged between 1.74 ± 0.16–4.47 ± 0.43 mm and width ranged between 1.06 ± 0.08–3.44 ± 0.23 mm, showing various shapes. The irregular and elongated polygonal testa cells occurred in all investigated species. Seed testa sculptures showed high variation in their anticlinal walls associated with different shapes: straight to with U-, S- or Omega-type undulations among the species. The moderately flat to convex periclinal walls with various sized verrucae or granules were found in all investigated taxa. Based on our research, we conclude that seed characteristics such as size, shape, and the seed testa features show their significant variability, revealing key characteristics to support taxonomic relationships and major clades recovered in the molecular phylogeny of the genus Allium. Especially, the anticlinal wall characteristics were highly variable and decisive at the both section and species levels. In addition, widely varied shapes and sizes of the seeds were remarkably effective to distinguish Allium species.

Seed Morphometry of Native Indonesian Orchids in the Genus Dendrobium.

In this study, seeds of 10 species of epiphytic orchids were examined using light and scanning electron microscope. Quantitative and qualitative characters were analyzed. All the presently investigated seeds showed are transparent with visible embryo and remarkable embryo color variations (such as pale yellow, light yellow, shiny yellow to yellow, orange, and white). The species showed two groups in seed shape (fusiform and filiform), prolate and oval-shaped embryo, positioned at the center of the long axis and near apical pole. Embryo in prolate shaped and near apical pole position was only in D. antennatum. Based on our investigation, there are variations in seed and embryo volume as well as percentage air space in different taxa of orchids. The highest air space percentages were found in D. leporinum. According to the ornamentation of testa cells, 3 types of seeds were discovered in this genus. Additionally, the clear variation in the testa ornamentation pattern includes the species of D. leporinum, where the testa cells were in the medial regular rectangles, but in the apical and basal pole they are polygonal and irregularly oriented; the testa cells of D. antennatum are polygonal and irregularly oriented and those of D. purpureum are longitudinally oriented with regular rectangles.

Fruit and seed micromorphology and its systematic significance in tribe Sorbarieae (Rosaceae)

We investigated fruit and seed morphology in tribe Sorbarieae and one traditionally included genus (Lyonothamnus), which revealed that these characteristics are taxonomically significant for generic delimitation in the tribe Sorbarieae, and two distinct groups in the genus Sorbaria were identified. The following fruit and seed micromorphological characteristics were described: size, shape, texture, the presence/absence of epicuticular wax and, trichomes, testa cell size, and surface ornamentation. Multicellular capitate glands with stalks were only observed on the follicle surfaces of Lyonothamnus. Simple unbranched unicellular non-glandular trichomes were found on the follicles of Chamaebatiaria millefolium, Sorbaria grandiflora, S. sorbifolia complex, and Spiraeanthus schrenkianus. However, Sorbaria arborea complex, S. kirilowii, and S. tomentosa complex had platelet epicuticular wax on their glabrous follicles. Moreover, four types of testa ornamentation were identified: type I, colliculate (Lyonothamnus); type II, reticulate, with straight anticlinal walls and smooth to micro-papillate periclinal walls (Chamaebatiaria); type III, reticulate, with undulate anticlinal walls and smooth periclinal walls (Spiraeanthus); and type IV, reticulate testa ornamentation and divided into two subtypes based on anticlinal and periclinal cell wall patterns (Sorbaria). These studied characteristics identified using principal component analysis may have diagnostic importance among the taxa in the tribe. Our fruit and seed micromorphological results provide strong evidence that genus Lyonothamnus could be positioned in the tribe Lyonothamneae, not Sorbarieae. Moreover, these data supported the preliminary phylogenetic hypothesis that Sorbaria could be divided into two groups.

Seed micromorphological study on endemic and subendemic species of <i>Veronica</i> L. (Plantaginaceae Juss.) in Iran

Seed morphology of 12 Iranian endemic and subendemic species of Veronica was studied using scanning electron microscope (SEM). Seven qualitative and quantitative characters were measured using SEM micrographs and stereomicroscopy. The seed shape of most species is ovate and plano-convex. The size of seeds ranges from 1.25 x 0.75 mm in V. khorassanica to 2.5 x 1.75 mm in V. viscosa Boiss. The ornamentation of seed coat is reticulate-verrucate in V. khorassanica, V. czerniakowskiana, V. mazanderanae and V. rubrifolia, reticulate-rugate in V. acrotheca, V. aucheri, V. viscosa and V. intercedens, rugose in V. microcarpa, V. chionantha and V. rechingeri, and reticulate-porate in V. gaubae. The testa cells are polygonal in ten species and irregular in two species. Micromorphological characters of seeds are useful in specific and subspecific delimitations of Iranian Veronica.

Variations in seed micromorphology and morphometry of native Indonesian Phalaenopsis and Paphiopedilum orchids

Abstract. Hariyanto S. 2019. Variations in seed micromorphology and morphometry of native Indonesian Phalaenopsis and Paphiopedilum orchid. Biodiversitas 20: 3559-3567. Seeds of ten taxa of the genera Phalaenopsis and Paphiopedilum orchids were studied using light and scanning electron microscopy (SEM). Qualitative characters (seed and embryo shape, seed and embryo colour, ornamentation of testa cell, testa cell wall shape) as well as quantitative data (seed and embryo length, seed and embryo width, seed and embryo volume, seed length/seed width, embryo length/embryo width, seed volume/embryo volume and air space) were analysed. Seeds of all studied taxa were fusiform in shape and had smooth testa surfaces. Phalaenopsis testa cells were elongated with cylindrical cell walls, while Paphiopedilum testa cells were polygonal with thin and flat rectangular cell walls. The shape of the embryos was generally ovoid in Phalaenopsis and prolate in Paphiopedilum. Seed colors ranged from brown to dark brown. Embryo colors varied from light yellow, yellowish-brown, dark brown, black and white. Based on our investigation, there are variations in seed and embryo length, seed and embryo width, seed and embryo volume as well as the percentage of the air space, both in Phalaenopsis and Paphiopedilum. In general, the values of seed volume, embryo volume and air space in Paphiopedilum are higher than in Phalaenopsis. Together, the results of the study indicate that morphological and morphometric features can serve to identify live forms and distinguish between species.

Seed coat polymorphism in Vigna section Aconitifoliae in India

The seed coat polymorphism of 50 accessions representing five species of Vigna section Aconitifoliae (subgenus Ceratotropis) was investigated using scanning electron microscopy (SEM) in order to evaluate the interspecific and intraspecific variations of various morphoanatomical seed traits. Seed shape, hilum structure aril and testa pattern were examined. The seed coat pattern was found to be a significant character for species delimitation. The testa cell size and ornamentation showed distinctive intra- and interspecific variations across the examined species. The results revealed that the wild accessions of V. aconitifolia (I-aco and II-aco), V. indica (I-ind and II-ind), V. stipulacea (I-sti, I-sti, II-sti, III-sti and VI-sti) and V. trilobata (I-tri, II-tri) have different seed coat types. In the present study, only a single seed coat pattern was recorded for the endemic, threatened species V. khandalensis. Finally, the congruency of seed coat patterns optimized onto an rDNA-ITS phylogeny was discussed.