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The silhouettes of 40 seeds of each of the species of Silene grouped according to subgenus (S. subg. Behenantha in red; S. subg. Silene in blue). The seed silhouettes have been scaled to fit a common proportional size without affecting shape.
Source publication
Seed description in morphology is often based on adjectives such as “spherical”, “globular”, or “reniform”, but this does not provide a quantitative method. A new morphological approach based on the comparison of seed images with geometric models provides a seed description in Silene species on a quantitative basis. The novelty of the proposed meth...
Contexts in source publication
Context 1
... images of Silene seeds resemble cardioids or modified cardioids: Figure 5 Table 5. Values of J index with the cardioid as a model in Silene species (subg. ...
Context 2
... comparisons of the seed images with the cardioid gave good results (J index superior to 90) with many species in both subgenera, but our interest is to obtain models specific for particular species, i.e., that give high values with one species and low in the others. The observation of the composed images of the seed silhouettes ( Figure 5) suggested that other cardioid-derived models could fit better the shape of some species. Models 2, 3 and 4 were specifically designed to increase values of J index in particular species. ...
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Citations
... The genus Silene L. (Family Caryophyllaceae) consists of ca. 850-900 species distributed in the Mediterranean region and Asia (Oxelman et al., 2000;Jafari et al., 2020;Martıń-Goḿez et al., 2020). In the flora of Egypt, Silene is represented by 29 species, three of which (Silene leucophylla Boiss., S. schimperiana Boiss., and S. oreosinaica Chowdhuri) are exclusive endemics to the St. Catherine Protectorate (Boulos, 2009). ...
One of the most crucial steps in the practical conservation of endangered endemic mountain plants is to address their population size status and habitat requirements concurrently with understanding their response to future global warming. Three endangered Silene species-Silene leucophylla Boiss., S. schimperiana Boiss., and S. oreosinaica Chowdhuri-in Egypt were the focus of the current study. These species were examined for population status change, habitat quality variables (topography, soil features, and threats), and predictive current and future distributions. To find population size changes, recent field surveys and historical records were compared. Using Random Forest (RF) and Canonical Correspondence Analysis (CCA), habitat preferences were assessed. To forecast present-day distribution and climate change response, an ensemble model was used. The results reported a continuous decline in the population size of the three species. Both RF and CCA addressed that elevation, soil texture (silt, sand, and clay fractions), soil moisture, habitat-type, chlorides, electric conductivity, and slope were among the important variables associated with habitat quality. The central northern sector of the Saint Catherine area is the hotspot location for the predictive current distribution of three species with suitable areas of 291.40, 293.10, and 58.29 km 2 for S. leucophylla, S. schimperiana, and S. oreosinaica, respectively. Precipitation-related variables and elevation were the key predictors for the current distribution of three Silene species. In response to climate change scenarios, the three Silene species exhibited a gradual contraction in the predictive suitable areas with upward shifts by 2050 and 2070. The protection of these species and Frontiers in Plant Science
... The species of the same genus or even the same family may have great differences in staining conditions, so it is necessary to adjust the method of each specific species when performing TZ-staining test on seeds (Lamarca and Barbedo, 2014). The closely related species have similar staining characteristics due to the similarity in morphology (Adams et al., 2005;Martín-Gómez et al., 2020), composition and so on. T. miqueliana and T. henryana belong to the genus Tilia, except for different seed treatment methods, the staining conditions are completely the same, so that other species of the same genus may also have similar TZ-staining conditions. ...
The assessment of seed quality and physiological potential is essential in seed production and crop breeding. In the process of rapid detection of seed viability using tetrazolium (TZ) staining, it is necessary to spend a lot of labour and material resources to explore the pretreatment and staining methods of hard and solid seeds with physical barriers. This study explores the TZ staining methods of six hard seeds ( Tilia miqueliana , Tilia henryana, Sassafras tzumu , Prunus subhirtella , Prunus sibirica , and Juglans mandshurica ) and summarizes the TZ staining conditions required for hard seeds by combining the difference in fat content between seeds and the kinship between species, thus providing a rapid viability test method for the protection of germplasm resources of endangered plants and the optimization of seed bank construction. The TZ staining of six species of hard seeds requires a staining temperature above 35 °C and a TZ solution concentration higher than 1%. Endospermic seeds require shorter staining times than exalbuminous seeds. The higher the fat content of the seeds, the lower the required incubation temperature and TZ concentration for staining, and the longer the staining time. And the closer the relationship between the two species, the more similar their staining conditions become. The TZ staining method of similar species can be predicted according to the genetic distance between the phylogenetic trees, and the viability of new species can be detected quickly.
... The J index was calculated by comparing the seed silhouette with lateral models LM1 and LM2 derived from a cardioid, and dorsal models DM2 and DM3 derived from a modified ellipse, according to Martıń-Goḿez et al. (2020); Juan et al. (2021), and Rodrıǵuez-Lorenzo et al. (2022). For the elliptic Fourier analysis, we started from a binary image with silhouettes, and using the package OutlineR, the outlines were extracted and loaded into the R environment according to Matzig (2021). ...
Introduction
Plants undergo various natural changes that dramatically modify their genomes. One is polyploidization and the second is hybridization. Both are regarded as key factors in plant evolution and result in phenotypic differences in different plant organs. In Silene, we can find both examples in nature, and this genus has a seed shape diversity that has long been recognized as a valuable source of information for infrageneric classification.
Methods
Morphometric analysis is a statistical study of shape and size and their covariations with other variables. Traditionally, seed shape description was limited to an approximate comparison with geometric figures (rounded, globular, reniform, or heart-shaped). Seed shape quantification has been based on direct measurements, such as area, perimeter, length, and width, narrowing statistical analysis. We used seed images and processed them to obtain silhouettes. We performed geometric morphometric analyses, such as similarity to geometric models and elliptic Fourier analysis, to study the hybrid offspring of S. latifolia and S. dioica.
Results
We generated synthetic tetraploids of Silene latifolia and performed controlled crosses between diploid S. latifolia and Silene dioica to analyze seed morphology. After imaging capture and post-processing, statistical analysis revealed differences in seed size, but not in shape, between S. latifolia diploids and tetraploids, as well as some differences in shape among the parentals and hybrids. A detailed inspection using fluorescence microscopy allowed for the identification of shape differences in the cells of the seed coat. In the case of hybrids, differences were found in circularity and solidity. Overal seed shape is maternally regulated for both species, whereas cell shape cannot be associated with any of the sexes.
Discussion
Our results provide additional tools useful for the combination of morphology with genetics, ecology or taxonomy. Seed shape is a robust indicator that can be used as a complementary tool for the genetic and phylogenetic analyses of Silene hybrid populations.
... A quantitative method based on the comparison with geometric models has been applied to describe, quantify and compare seed shape in diverse families and species [32][33][34][35]. The application of this method to the seeds of the Cucurbitaceae showed the similarity that many seeds have with ellipses and ovoids [35] and gave quantifications of shape for some species. ...
... Bilateral symmetry of a seed was calculated based on the protocol to obtain J index. J index is the percentage of similarity between a plane figure of a seed and the corresponding geometric model [32][33][34][35]. The model used to calculate bilateral symmetry is the specular image of the seed silhouette obtained with the command reflect horizontally in Corel PhotoPaint ( Figure 2). ...
Quantitative morphological methods have been applied here to seed morphology in species representative of the Cucurbitaceae: Curvature analysis, symmetry analysis and the comparison with geometric models. The three methods were applied to the comparison of three species and two varieties of Cucumis, and the results indicate that both symmetry analysis and the comparison with geometric models can be useful for the identification and classification of species and varieties in Cucumis. Curvature analysis reveals differences between species of the Cucurbitaceae, and, together with other quantitative morphological measurements, like circularity, aspect ratio and solidity, may provide valuable information and be an interesting tool for taxonomy in this family.
... Therefore, at this stage, an important direction in the study of biological diversity is the study of morphometric and weight indicators of individual taxa. Fortunately, more and more work can be seen using seed structure data based on diverse methods for various taxonomical groups of plants (Gabr 2018;Martín-Gómez et al. 2019;Martín-Gómez et al. 2020;Rewicz et al. 2020;Rashid et al. 2021;Rewicz et al. 2022;Bai et al. 2023). ...
Sumbembayev AA, Lagus OA, Nowak S. 2023. Seed morphometry of Rheum L. (Polygonaceae) species from Kazakhstan and its implications in taxonomy and species identification. Biodiversitas 24: 4677-4692. In the article, the evaluation of morphometric and weight parameters of seeds of 7 species of the genus Rheum L. from Kazakhstan is presented, as well as an analysis of their biometric parameters from different ecological and geographical habitats. The purpose of the study was to determine the variability of the seeds of the studied taxa and the importance of the results in determining the taxonomic relationships within the genus. The external structure was described for all species of the genus. Seeds of all studied species are illustrated with photos and scale drawings, and their features are summarized in a table. Stable and taxonomically significant features were identified for the species of the section Ribesiformia, represented by R. cordatum and R. maximowiczii, allowing their identification. The correlation between seed metric parameters and environmental conditions of the site and growth area was established and found a significant relationship between morphometric data and most of the environmental factors studied. The low adaptive potential of rhubarb species in Kazakhstan and the species' narrow ecological range were found. The comparison of the results obtained with the taxonomic relationships and phylogeny of representatives of the genus are briefly discussed.
... 800 species, is the largest genus in the Caryophyllaceae. Silene seeds have a characteristic shape in the lateral view that may be described and quantified by comparison with a cardioid and derived figures [16][17][18]. ...
In the Caryophyllaceae, seed surfaces contain cell protrusions, of varying sizes and shapes, called tubercles. Tubercles have long been described in many species, but quantitative analyses with measurements of size and shape are lacking in the literature. Based on optical photography, the seeds of Silene were classified into four types: smooth, rugose, echinate and papillose. Seeds in each of these groups have characteristic geometrical properties: smooth seeds lack tubercles and have the highest values of circularity and solidity in their lateral views, while papillose seeds have the largest tubercles and lowest values of circularity and solidity both in lateral and dorsal views. Here, tubercle width, height and slope, maximum and mean curvature values and maximum to mean curvature ratio were obtained for representative seeds of a total of 31 species, 12 belonging to Silene subg. Behenantha and 19 to S. subg. Silene. The seeds of the rugose type had lower values of curvature. Additionally, lower values of curvature were found in species of S. subg. Silene in comparison with S. subg. Behenantha. The seeds of S. subg. Behenantha had higher values of tubercle height and slope and higher values of maximum and average curvature and maximum to mean curvature ratio.
... The Caryophyllaceae Juss. comprises ca. 100 genera and 3000 species of herbs and small shrubs [1,2] of a cosmopolitan distribution and characterized by a peripheral position of the embryo in the developing seed [3], anatropous to campylotropous ovules [4], with an interesting diversity in seed shape [5][6][7][8][9][10][11][12][13][14]. ...
... Morphological analysis of seeds in the Caryophyllaceae focuses on two aspects: overall seed shape and detailed seed surface structure. Cardioid-derived models have been applied to the quantification of overall shape in lateral views of the seed [5][6][7], while ellipse-based models fit well to dorsal views of the seed in many species [8]. The application of models to seed shape quantification contributes to the identification of useful characters for taxonomy. ...
... Behenantha conform better to a cardioid than those of Silene subg. Silene [5]. Seed images of species of sect. ...
The application of seed morphology to descriptive systematics requires methods for shape analysis and quantification. The complexity of lateral and dorsal views of seeds of Silene species is investigated here by the application of the Elliptic Fourier Transform (EFT) to representative seeds of four morphological types: smooth, rugose, echinate and papillose. The silhouettes of seed images in the lateral and dorsal views are converted to trigonometric functions, whose graphical representations reproduce them with different levels of accuracy depending on the number of harmonics. A general definition of seed shape in Silene species is obtained by equations based on 40 points and 20 harmonics, while the detailed representation of individual tubercles in each seed image requires between 100 and 200 points and 60-80 harmonics depending on their number and complexity. Smooth-type seeds are accurately represented with a low number of harmonics, while rugose, echinate and papillose seeds require a higher number. Fourier equations provide information about tubercle number and distribution and allow the analysis of curvature. Further estimation of curvature values in individual tubercles reveals differences between seeds, with higher values of curvature in S. latifolia, representative of echinate seeds, and lower in S. chlorifolia with rugose seeds.
... Several species from S. subg. Behenantha showed classification problems in phylogenetic analysis and morphological studies [29,34]. According to [34], specific morphological analysis have been recommended to complement Silene taxonomic work. ...
... Similarly, the section dedicated to Silene for Flora Iberica [37], reports obtuse tubercles for S. latifolia ( [37], p. 396). We have worked so far with a total of 16 populations of S. latifolia from Central Europe and diverse locations in Southern Spain, France and Italy ( [29][30][31][32] and unpublished results) and finding differences in the length and acuteness of the protuberances, but these seeds were all classified as echinate seeds based on the silhouette morphology. Although some individual seeds for some populations may lack echinate protuberances, in most of them the protuberances are obvious (pers. ...
... The seed individual outlines and their corresponding average silhouettes for the lateral and dorsal views of the seeds in each species were obtained from 20 representative seed images by the method described [29,38]. A video describing the method used is available at: https://zenodo.org/record/4478344#.YzxbmExBxD8 (accessed on 1 December 2022). ...
Seed morphology is an important source of information for plant taxonomy. Nevertheless, the characters under study are diverse, and a simple, unified method is lacking in the literature. A new method for the classification of seeds of the genus Silene based on optical images and image analysis has recently been described on the basis of morphological measurements of the lateral seed views. According to the outline of their silhouettes, seeds from 52 species (49 of Silene and three related species) were classified in three groups: smooth, rugose and echinate, revealing remarkable differences between these groups. This methodology has been applied here to 51 new species, making a total of 100 species of Silene analyzed so far. According to our data, a new group was described, termed papillose. The results showed morphological differences between the four mentioned seed groups, with reduced values of circularity for dorsal and lateral seed views in the papillose and echinate groups and reduced values of solidity in the papillose seeds. The method was applied to the analysis of individual as well as to average seed silhouettes and some of the differences between groups were maintained in both cases.
... The seeds of the Silene species resemble in their lateral views the cardioid and related figures, which can be used as models for the quantification of seed shape. The models used in the quantification of lateral and dorsal views of Silene can be obtained by the representation of diverse algebraic equations [5][6][7][8][9], thus switching the morphological description of seeds from purely descriptive to a quantitative, analytical method. ...
... Seeds of the Caryophyllaceae present interesting features, with ovules hemianatropous to campylotropous [18][19][20], and the embryo corresponds to a peripheral type [21]. The genus Silene L. has an interesting diversity of seed shapes and is proposed here as a model for studying variations in seed morphology [5][6][7][8][9]. ...
... In both cases, the process requires a manual seed image-model adjustment, which does not impede achieving objective and reproducible values. Seed shape quantification by comparing seed images with canonical models has been applied to various plant species [5][6][7][8][9][11][12][13][14][15][16][17][25][26][27][28][29][30][31][32][33][34]. ...
Historically, little attention has been paid to the resemblance between seed silhouettes to geometric figures. Cardioid and derivatives, ellipses, heart curves, lemniscates, lenses, lunes, ovals, superellipses, waterdrops, and other figures can be used to describe seed shape, as well as models for quantification. Algebraic expressions representing the average silhouettes for a group of seeds are available, and their shape can be described and quantified by comparison with geometric models. Bidimensional closed-plane figures resulting from the representation of Fourier equations can be used as models for shape analysis. Elliptic Fourier Transform equations reproduce the seed silhouettes for any closed-plane curve corresponding to the contour of the image of a seed. We review the geometric properties of the silhouettes from seed images and discuss them in the context of seed development, plant taxonomy, and environmental adaptation. Silene is proposed as a model for the study of seed morphology. Three groups have been recently defined among Silene species based on the structure of their seed silhouettes, and their geometric properties are discussed. Using models based on Fourier Transform equations is useful in Silene species where the seeds are homogenous in shape but don’t adjust to described figures.
... In addition to dealing with different species according to the flora of each country, the characteristics that are the object of study are diverse and defined differently for each group. The availability of methods for the description of seed morphology based on simple morphological techniques may be a tool for the taxonomy of this genus [20][21][22]. ...
... In previous work, we described and quantified seed shape by comparison with geometric models because Silene species present an interesting diversity of seed shapes. In their lateral views, they resemble cardioid or cardioid-derived figures [20,21], while a range of geometric figures may serve as models for the dorsal views [22]. For both the lateral and dorsal views of seeds, species were classified by their similarity to different geometric models defined by algebraic equations (LM and DM stand, respectively, for lateral and dorsal models). ...
... The J index for the model LM1 (the cardioid) had values above 90 in 12 species of Silene subg. Behenantha [20,21]. These species were: S. acutifolia Link ex Rohrb., S. conica L., S. diclinis (Lag.) ...
Silene taxonomy, traditionally based on morphological characteristics, is now driven by DNA sequence analysis. While the usefulness of both morphological and molecular methods remains undisputed, there is an interest in the identification of the morphological characteristics useful in taxonomy. A quantitative morphological analysis of seeds belonging to Silene species is presented here and is based on seed image samples for 95 populations belonging to 52 species (49 species of Silene and 3 related species). According to the silhouette of lateral views of their seed images, Silene species are classified into three groups: smooth, rugose and echinate. The measurements taken for the lateral and dorsal views of the seeds include area, circularity, roundness, aspect ratio and solidity; differences between groups are found for all characteristics. Solidity is the ratio between the area of the seed silhouette and the corresponding convex hull. It is related to seed convexity and is the measurement with the lowest coefficient of variation. In the lateral views, solidity values are conserved, while in the dorsal views, differences are found between the three groups. The group of echinate seeds has the highest values of solidity in the dorsal views, and their species belong to S. subg. Behenantha and S. subg. Lychnis. The group of smooth seeds contains mainly species corresponding to S. subg. Silene, while species of S. subg. Lychnis are absent.
