ABSTRACT
For the Caatinga vegetation, it has not yet been definitively established which adaptive strategies best define the functional groups of woody plants and which syndromes emerge from the relationships between functional traits to achieve success in a semi-arid tropical region. To fill some of these gaps, we analyzed a specific set of characteristics that make up the LHS scheme of the plant ecological strategy (leaf-heigh-seed). The LHS scheme captures the functional niche of plants regarding the functional traits specific leaf area (SLA), plant height (HE), and seed mass (SM). We associate wood density (WD) to this scheme because this trait is a key feature for the identification of functional strategies in seasonally dry vegetation such as the Caatinga. We measured these characteristics in eight woody species and classified them according to their leaf phenology into deciduous and evergreen. The experiment was carried out between December 2017 and November 2018 in Caatinga areas located in the municipality of Barra de Santana, PB, a semiarid region of Brazil. Using cluster analysis, principal component analysis (PCA) and Pearson correlation analyses, we found significant relations between SLA and SM, and HE and WD. The SLA was the main predictor of plant strategy in the Caatinga. According to this characteristic, we identified two functional groups: species with a low SLA and species with a high SLA. We also recognized differences between deciduous and evergreen species based on the same trait. The traits measured, which represent the axes of the plant ecological strategy scheme LHS and wood density, are efficient in the discrimination of functional groups in the Brazilian semiarid. These groups relate to leaf phenology of woody species in this vegetation.
Subject(s)
Wood , Brazil , Wood/classification , Seasons , Plant Leaves/anatomy & histology , Plant Leaves/classification , Plant Leaves/physiology , Trees/classification , Seeds/classification , Seeds/anatomy & histology , Seeds/growth & development , Ecosystem , Tropical ClimateABSTRACT
The dimensions of organs such as flowers, leaves, and seeds are governed by processes of cellular proliferation and expansion. In soybeans, the dimensions of these organs exhibit a strong correlation with crop yield, quality, and other phenotypic traits. Nevertheless, there exists a scarcity of research concerning the regulatory genes influencing flower size, particularly within the soybean species. In this study, 309 samples of 3 soybean types (123 cultivar, 90 landrace, and 96 wild) were re-sequenced. The microscopic phenotype of soybean flower organs was photographed using a three-eye microscope, and the phenotypic data were extracted by means of computer vision. Pearson correlation analysis was employed to assess the relationship between petal and seed phenotypes, revealing a strong correlation between the sizes of these two organs. Through GWASs, SNP loci significantly associated with flower organ size were identified. Subsequently, haplotype analysis was conducted to screen for upstream and downstream genes of these loci, thereby identifying potential candidate genes. In total, 77 significant SNPs associated with vexil petals, 562 significant SNPs associated with wing petals, and 34 significant SNPs associated with keel petals were found. Candidate genes were screened by candidate sites, and haplotype analysis was performed on the candidate genes. Finally, the present investigation yielded 25 and 10 genes of notable significance through haplotype analysis in the vexil and wing regions, respectively. Notably, Glyma.07G234200, previously documented for its high expression across various plant organs, including flowers, pods, leaves, roots, and seeds, was among these identified genes. The research contributes novel insights to soybean breeding endeavors, particularly in the exploration of genes governing organ development, the selection of field materials, and the enhancement of crop yield. It played a role in the process of material selection during the growth period and further accelerated the process of soybean breeding material selection.
Subject(s)
Flowers , Genome-Wide Association Study , Glycine max , Phenotype , Polymorphism, Single Nucleotide , Glycine max/genetics , Glycine max/anatomy & histology , Glycine max/growth & development , Flowers/genetics , Flowers/anatomy & histology , Flowers/growth & development , Haplotypes , Quantitative Trait Loci , Seeds/genetics , Seeds/growth & development , Seeds/anatomy & histologyABSTRACT
BACKGROUND: Avena fatua and A. sterilis are challenging to distinguish due to their strong similarities. However, Artificial Neural Networks (ANN) can effectively extract patterns and identify these species. We measured seed traits of Avena species from 122 locations across the Balkans and from some populations from southern, western, and central Europe (total over 22 000 seeds). The inputs for the ANN model included seed mass, size, color, hairiness, and placement of the awn attachment on the lemma. RESULTS: The ANN model achieved high classification accuracy for A. fatua and A. sterilis (R2 > 0.99, RASE < 0.0003) with no misclassification. Incorporating geographic coordinates as inputs also resulted in successful classification (R2 > 0.99, RASE < 0.000001) with no misclassification. This highlights the significant influence of geographic coordinates on the occurrence of Avena species. The models revealed hidden relationships between morphological traits that are not easily detectable through traditional statistical methods. For example, seed color can be partially predicted by other seed traits combined with geographic coordinates. When comparing the two species, A. fatua predominantly had the lemma attachment point in the upper half, while A. sterilis had it in the lower half. A. sterilis exhibited slightly longer seeds and hairs than A. fatua, while seed hairiness and mass were similar in both species. A. fatua populations primarily had brown, light brown, and black colors, while A. sterilis populations had black, brown, and yellow colors. CONCLUSIONS: Distinguishing A. fatua from A. sterilis based solely on individual characteristics is challenging due to their shared traits and considerable variability of traits within each species. However, it is possible to classify these species by combining multiple seed traits. This approach also has significant potential for exploring relationships among different traits that are typically difficult to assess using conventional methods.
Subject(s)
Neural Networks, Computer , Seeds , Seeds/anatomy & histology , Avena/genetics , Avena/anatomy & histology , Balkan Peninsula , EuropeABSTRACT
KEY MESSAGE: Hyperspectral features enable accurate classification of soybean seeds using linear discriminant analysis and GWAS for novel seed trait genes. Evaluating crop seed traits such as size, shape, and color is crucial for assessing seed quality and improving agricultural productivity. The introduction of the SUnSet toolbox, which employs hyperspectral sensor-derived image analysis, addresses this necessity. In a validation test involving 420 seed accessions from the Korean Soybean Core Collections, the pixel purity index algorithm identified seed- specific hyperspectral endmembers to facilitate segmentation. Various metrics extracted from ventral and lateral side images facilitated the categorization of seeds into three size groups and four shape groups. Additionally, quantitative RGB triplets representing seven seed coat colors, averaged reflectance spectra, and pigment indices were acquired. Machine learning models, trained on a dataset comprising 420 accession seeds and 199 predictors encompassing seed size, shape, and reflectance spectra, achieved accuracy rates of 95.8% for linear discriminant analysis model. Furthermore, a genome-wide association study utilizing hyperspectral features uncovered associations between seed traits and genes governing seed pigmentation and shapes. This comprehensive approach underscores the effectiveness of SUnSet in advancing precision agriculture through meticulous seed trait analysis.
Subject(s)
Glycine max , Phenotype , Seeds , Glycine max/genetics , Seeds/genetics , Seeds/anatomy & histology , Genome-Wide Association Study/methods , Hyperspectral Imaging/methods , Pigmentation/genetics , Image Processing, Computer-Assisted/methods , Algorithms , Machine LearningABSTRACT
BACKGROUND: Seed retention is the basic prerequisite for seed harvest. However, only little breeding progress has been achieved for this trait in the major forage grasses. The aim of this study was to evaluate the potential of plant genetic resources of the important fodder grasses Festuca pratensis Huds. and Lolium perenne L. as source for seed retention in the breeding process. Furthermore, the morphology of the abscission zone, where shattering occurs, was studied on the cell tissue level in different developmental stages of contrasting accessions. RESULTS: 150 and 286 accessions of Festuca pratensis and Lolium perenne were screened for seed retention, respectively. Contrasting accessions were selected to be tested in a second year. We found a great variation in seed retention in Festuca pratensis and Lolium perenne, ranging from 13 to 71% (average: 35%) and 12 to 94% (average: 49%), respectively, in the first year. Seed retention was generally lower in the second year. Cultivars were within the accessions with highest seed retention in Festuca pratensis, but had lower seed retention than ecotypes in Lolium perenne. Field-shattered seeds had a lower thousand grain weight than retained seeds. Cell layers of the abscission zone appeared already in early seed stages and were nested within each other in accessions with high seed retention, while there were two to three superimposed layers in accessions with low seed retention. CONCLUSIONS: Plant genetic resources of Lolium perenne might be a valuable source for breeding varieties with high seed retention. However, simultaneous selection for high seed weight is necessary for developing successful commercial cultivars.
Subject(s)
Festuca , Lolium , Phenotype , Seeds , Lolium/growth & development , Lolium/genetics , Lolium/anatomy & histology , Festuca/genetics , Festuca/growth & development , Festuca/anatomy & histology , Seeds/growth & development , Seeds/genetics , Seeds/anatomy & histologyABSTRACT
There is some evidence that seed traits can affect the long-term persistence of seeds in the soil. However, findings on this topic have differed between systems. Here, we brought together a worldwide database of seed persistence data for 1474 species to test the generality of seed mass-shape-persistence relationships. We found a significant trend for low seed persistence to be associated with larger and less spherical seeds. However, the relationship varied across different clades, growth forms and species ecological preferences. Specifically, relationships of seed mass-shape-persistence were more pronounced in Poales than in other order clades. Herbaceous species that tend to be found in sites with low soil sand content and precipitation have stronger relationships between seed shape and persistence than in sites with higher soil sand content and precipitation. For the woody plants, the relationship between persistence and seed morphology was stronger in sites with high soil sand content and low precipitation than in sites with low soil sand content and higher precipitation. Improving the ability to predict the soil seed bank formation process, including burial and persistence, could benefit the utilization of seed morphology-persistence relationships in management strategies for vegetation restoration and controlling species invasion across diverse vegetation types and environments.
Subject(s)
Seed Bank , Seeds , Soil , Seeds/anatomy & histologyABSTRACT
Crops generally have seeds larger than their wild progenitors´ and with reduced dormancy. In wild plants, seed mass and allocation to the seed coat (a proxy for physical dormancy) scale allometrically so that larger seeds tend to allocate less to the coats. Larger seeds and lightweight coats might thus have evolved as correlated traits in crops. We tested whether 34 crops and 22 of their wild progenitors fit the allometry described in the literature, which would indicate co-selection of both traits during crop evolution. Deviations from the allometry would suggest that other evolutionary processes contribute to explain the emergence of larger, lightweight-coated seeds in crops. Crops fitted the scaling slope but deviated from its intercept in a consistent way: Seed coats of crops were lighter than expected by their seed size. The wild progenitors of crops displayed the same trend, indicating that deviations cannot be solely attributed to artificial selection during or after domestication. The evolution of seeds with small coats in crops likely resulted from a combination of various pressures, including the selection of wild progenitors with coats smaller than other wild plants, further decreases during early evolution under cultivation, and indirect selection due to the seed coat-seed size allometry.
Subject(s)
Biological Evolution , Biomass , Crops, Agricultural , Seeds , Crops, Agricultural/growth & development , Crops, Agricultural/anatomy & histology , Crops, Agricultural/physiology , Seeds/growth & development , Seeds/anatomy & histology , Seeds/physiologyABSTRACT
Proper pericarp thickness protects the maize kernel against pests and diseases, moreover, thinner pericarp improves the eating quality in fresh corn. In this study, we aimed to investigate the dynamic changes in maize pericarp during kernel development and identified the major quantitative trait loci (QTLs) for maize pericarp thickness. It was observed that maize pericarp thickness first increased and then decreased. During the growth and formation stages, the pericarp thickness gradually increased and reached the maximum, after which it gradually decreased and reached the minimum during maturity. To identify the QTLs for pericarp thickness, a BC4F4 population was constructed using maize inbred lines B73 (recurrent parent with thick pericarp) and Baimaya (donor parent with thin pericarp). In addition, a high-density genetic map was constructed using maize 10 K SNP microarray. A total of 17 QTLs related to pericarp thickness were identified in combination with the phenotypic data. The results revealed that the heritability of the thickness of upper germinal side of pericarp (UG) was 0.63. The major QTL controlling UG was qPT1-1, which was located on chromosome 1 (212,215,145-212,948,882). The heritability of the thickness of upper abgerminal side of pericarp (UA) was 0.70. The major QTL controlling UA was qPT2-1, which was located on chromosome 2 (2,550,197-14,732,993). In addition, a combination of functional annotation, DNA sequencing analysis and quantitative real-time PCR (qPCR) screened two candidate genes, Zm00001d001964 and Zm00001d002283, that could potentially control maize pericarp thickness. This study provides valuable insights into the improvement of maize pericarp thickness during breeding.
Subject(s)
Chromosome Mapping , Quantitative Trait Loci , Zea mays , Quantitative Trait Loci/genetics , Zea mays/genetics , Zea mays/anatomy & histology , Zea mays/growth & development , Seeds/genetics , Seeds/growth & development , Seeds/anatomy & histology , Phenotype , Chromosomes, Plant/genetics , Polymorphism, Single NucleotideABSTRACT
Winged, autorotating seeds from the genus Acer, have been the subject of study for botanists and aerodynamicists for decades. Despite this attention and the relative simplicity of these winged seeds, there are still considerable gaps in our understanding of how samara dynamics are informed by morphological features. Additionally, questions remain regarding the robustness of their dynamics to morphological alterations such as mass change by moisture or area change by damage. We here challenge the conventional approach of using wing-loading correlations and instead demonstrate the superiority of a classical aerodynamic model. Using allometry, we determine why some species deviate from interspecific aerodynamic behavior. We alter samara mass and wing area and measure corresponding changes to descent velocity, rotation rate, and coning angle, thereby demonstrating their remarkable ability to autorotate despite significant morphological alteration. Samaras endure mass changes greater than 100% while maintaining descent velocity changes of less than 15%, and are thus robust to changes in mass by moisture or damage. Additionally, samaras withstand up to a 40% reduction in wing area before losing their ability to autorotate, with the largest wings more robust to ablation. Thus, samaras are also robust to wing damage in their environment, a fact children joyfully exploit.
Subject(s)
Acer , Animals , Child , Humans , Seeds/anatomy & histology , Wings, Animal/anatomy & histologyABSTRACT
Grain size is a crucial agronomic trait that affects stable yield, appearance, milling quality, and domestication in rice. However, the molecular and genetic relationships among QTL genes (QTGs) underlying natural variation for grain size remain elusive. Here, we identified a novel QTG SGW5 (suppressor of gw5) by map-based cloning using an F2 segregation population by fixing same genotype of the master QTG GW5. SGW5 positively regulates grain width by influencing cell division and cell size in spikelet hulls. Two nearly isogenic lines exhibited a significant differential expression of SGW5 and a 12.2% increase in grain yield. Introducing the higher expression allele into the genetic background containing the lower expression allele resulted in increased grain width, while its knockout resulted in shorter grain hulls and dwarf plants. Moreover, a cis-element variation in the SGW5 promoter influenced its differential binding affinity for the WRKY53 transcription factor, causing the differential SGW5 expression, which ultimately leads to grain size variation. GW5 physically and genetically interacts with WRKY53 to suppress the expression of SGW5. These findings elucidated a new pathway for grain size regulation by the GW5-WRKY53-SGW5 module and provided a novel case for generally uncovering QTG interactions underlying the genetic diversity of an important trait in crops.
Subject(s)
Edible Grain , Gene Expression Regulation, Plant , Oryza , Plant Proteins , Quantitative Trait Loci , Oryza/genetics , Oryza/anatomy & histology , Oryza/growth & development , Plant Proteins/genetics , Plant Proteins/metabolism , Quantitative Trait Loci/genetics , Edible Grain/genetics , Edible Grain/anatomy & histology , Edible Grain/growth & development , Genes, Plant , Promoter Regions, Genetic/genetics , Alleles , Phenotype , Transcription Factors/genetics , Transcription Factors/metabolism , Seeds/genetics , Seeds/growth & development , Seeds/anatomy & histology , Protein BindingABSTRACT
PREMISE: The representatives of the ANA-grade angiosperms demonstrate a diverse pattern of morphological characters, but their apocarpous gynoecium (except in Nymphaeaceae), composed of at least partly ascidiate carpels, the four-nucleate and four-celled female gametophyte, and the diploid endosperm (except in Amborella) are inferred to be plesiomorphies. Since the structure of fruits in Austrobaileyales is under-investigated, this research aims to fill this gap in these data, describing the carpological characters of ANA-grade taxa, and potentially illuminating the ancestral fruit and seed types of angiosperms. METHODS: The pericarp and seed coat anatomy was studied with light microscopy. The character optimization was carried out using WinClada software. RESULTS: The fruits of Austrobaileya, Trimenia, Kadsura, and Schisandra are determined to be apocarpous berries of the Schisandra type, with a parenchymatous pericarp and mesotestal (Austrobaileya) or exomesotestal seeds (other genera). Most inferred scenarios of fruit evolution indicate that the apocarpous berry is either the most probable plesiomorphic fruit type of all angiosperms, or that of all angiosperms except Amborellaceae. This inference suggests the early origin of the berry in fruit evolution. The plesiomorphic seed type of angiosperms according to reconstructed scenarios of seed type evolution was either a seed lacking a sclerenchymatous layer or an exotestal seed. CONCLUSIONS: The current research indicates that an apocarpous berry, and not a follicle, is a probable plesiomorphic character of the ANA-grade taxa and of angiosperms as a whole.
Subject(s)
Fruit , Magnoliopsida , Fruit/genetics , Fruit/anatomy & histology , Magnoliopsida/anatomy & histology , Seeds/genetics , Seeds/anatomy & histology , EndospermABSTRACT
Ontogenetic shape change has long been recognized to be important in generating patterns of morphological diversity and may be especially important in plant reproductive structures. We explore how seed cone disparity in Cupressaceae changes over ontogeny by comparing pollination-stage and mature cones. We sampled cones at pollen and seed release and measured cone scales using basic morphometric shape variables. We used multivariate statistical methods, particularly hypervolume overlap calculations, to measure morphospace occupation and disparity. Cone scales at both pollination and maturity exhibit substantial variability, although the disparity is greater at maturity. Mature cone scales are also more clustered in trait space, showing less overlap with other taxa than at pollination. These patterns reflect two growth strategies that generate closed cones over maturation, either through thin laminar scales or relatively thick, peltate scales, resulting in two distinct regions of morphospace occupation. Disparity patterns in Cupressaceae seed cones change over ontogeny, reflecting shifting functional demands that require specific patterns of cone scale growth. The evolution of Cupressaceae reproductive disparity therefore represents selection for trajectories of ontogenetic shape change, a phenomenon that should be widespread across seed plants.
Subject(s)
Cupressaceae , Seeds , Seeds/growth & development , Seeds/anatomy & histology , Cupressaceae/growth & development , Cupressaceae/physiology , Cupressaceae/anatomy & histology , Pollination , Pollen/growth & development , Pollen/physiologyABSTRACT
BACKGROUND: Capparis spinosa L. is a typical desert plant that is resistant to high temperatures and drought, and at the same time is rich in medicinal and food values. The objective of this study is to explore the variations in nutrient composition, morphological characteristics, and SDS-PAGE patterns of caper seeds from different provenances, aiming to provide insights for the selection of superior seed provenances. RESULTS: In this experiment, there were significant differences in the morphological characteristics and major nutritional components of caper seeds from different provenances. Seeds from the YKL (Karayagaqi Township, Yining County) and YKG (G218, KashiTown, Yining County) regions were larger in size compared to seeds from other regions. Among the four measured nutritional components, crude fat had the highest content, especially in the YKL and YKG region. The results of correlation analysis showed that crude fat was negatively correlated with soluble sugar and soluble protein but significantly positively correlated with starch content. As longitude increased from east to west, the morphological characteristics gradually increased. Based on the principal component analysis of all the parameters of the seeds, the eight provenances could be classified into three groups. HM (Hami), TGS (S202, Gaochang District, Turpan), HYW (Wubao Town, Yizhou District, Hami), TQQ (Qiquanhu Town, Turpan), and TLF (Turpan) were a group with higher soluble protein, soluble sugar, and water content. YKL and YKG were in one group, which had larger seed grains with high crude fat and starch content. AKS (Aksu) was in a separate group. The protein fractions from seeds of eight regions were extracted using Osborne fractionation method, it was found that glutelin content was the highest, while albumin content was the lowest. After these proteins were analyzed by SDS-PAGE, the electrophoretic patterns showed that the protein molecular weights were relatively small, and there were differences in protein bands among different provenances. CONCLUSION: According to the PCA results, the eight seed provenances could be divided into three groups. There were both geographically distant ones clustered into one group, and those close to each other were also divided into one group. There were differences in seed morphology, nutrient content and SDS-PAGE profiles among the different seed sources. This difference might be caused by a combination of geographic and climatic factors. In addition, YKL and YKG were roughly selected as good seed provenances, which provided a theoretical basis for the development of C. spinosa L. germplasm resources.
Subject(s)
Capparis , Capparis/anatomy & histology , Seeds/anatomy & histology , Electrophoresis, Polyacrylamide Gel , Sugars , StarchABSTRACT
PREMISE: Variation in fruit and seed traits could originate from selection pressures exerted by frugivores or other ecological factors (adaptive hypotheses) and developmental constraints (by-product hypotheses) or chance. METHODS: We evaluated fruit and leaf traits for nearly 850 plant species from a rainforest in Tinigua Park, Colombia. Through a series of linear regressions controlling for the phylogenetic signal of the traits (minimum N = 542), we tested (1) whether the allometry between seed width and length depends on seed dispersal system (Mazer and Wheelwright's adaptive hypothesis of allometry for species dispersed in the guts of animals = endozoochory) and (2) whether fruit length is associated with leaf length (i.e., Herrera's by-product hypothesis derived from the assumption that both organs develop from homologous structures). RESULTS: We found a strong negative allometric association between seed width and length for seeds of endozoochorous species, as expected; but also, for anemochorous species. We found a positive relationship between fruit and leaf length, but this relationship was not evident for zoochorous species. Fruit size was highly correlated with seed size. CONCLUSIONS: The allometry between seed length and width varied among dispersal systems, supporting that fruit and seed morphology has been modified by interactions with frugivores and by the possibility to rotate for some wind dispersed species. We found some support for the hypothesis on developmental constraints because fruit and leaf size were positively correlated, but the predictive power of the relationship was low (10-15%).
PREMISA: La variación en los rasgos de frutos y semillas de las plantas podría tener su origen en las presiones de selección ejercidas por los frugívoros u otros factores ecológicos (hipótesis adaptativas), así como en limitaciones del desarrollo (hipótesis de subproductos) o en el azar. MÉTODOS: Nosotros evaluamos rasgos de frutos y hojas en cerca de 850 especies de plantas de un bosque húmedo tropical en el Parque Nacional Natural Tinigua, Colombia. Usando una serie de regresiones lineales que controlan por la señal filogenética de dichos rasgos (mínimo N = 542), nosotros probamos (1) si la alometría entre el ancho y largo de la semilla depende del sistema de dispersión de la semilla (i.e., hipótesis adaptativa de Mazer y Wheelwright; en la que se espera una alometría negativa para especies dispersadas por endozoocoria) y (2) si el largo del fruto está asociado con el largo de la hoja (i.e., la hipótesis del subproducto de Herrera derivada de la suposición de que ambos órganos se desarrollan a partir de estructuras homólogas). RESULTADOS: Nosotros encontramos una fuerte asociación alométrica negativa entre el ancho y el largo de las semillas para las semillas de las especies endozoócoras, como era de esperar; pero también, para las especies anemócoras. Nosotros también hallamos una relación positiva entre el largo del fruto y de la hoja, pero esta relación no fue evidente para las especies endozoócoras. Detectamos que el tamaño del fruto esta altamente correlacionado con el tamaño de la semilla. CONCLUSIONES: La alometría entre el largo y el ancho de la semilla varió entre sistemas de dispersión, lo que sugiere que la morfología de frutos y semillas ha sido moldeada por interacciones con frugívoros en el caso de las semillas endozoócoras y por la posibilidad de rotar para algunas especies dispersadas por el viento. Aunque el poder predictivo de la relación entre el tamaño del fruto y de la hoja fue bajo (10-15%), nosotros encontramos un apoyo moderado a la hipótesis sobre las limitaciones del desarrollo, ya que el tamaño del fruto y de la hoja estaban correlacionados positivamente.
Subject(s)
Fruit , Seed Dispersal , Animals , Fruit/anatomy & histology , Rainforest , Phylogeny , Seeds/anatomy & histology , Plant LeavesABSTRACT
The seed morphology of 40 taxa within the genus Hypericum (Hypericaceae) from China, representing 9 sections of the genus, was examined using both Light and Scanning Electron Microscopy to evaluate the taxonomic relevance of macro- and micro-morphological features. Details articulating variation in seed size, color, shape, appendages, and seed coat ornamentation are described, illustrated, and compared, and their taxonomic importance is discussed. Seeds were generally brown in color and cylindric-ellipsoid to prolonged cylindric in shape. Seed size displayed wide variation, ranging from 0.37-1.91 mm in length and 0.12-0.75 mm in width. Seed appendages were observed as a characteristic morphological feature. Seed surface ornamentation has high phenotypic plasticity, and four types (reticulate, foveolate, papillose, and ribbed) can be recognized. In general, seed color and shape have limited taxonomic significance. However, some other features represent informative characters that can be used efficiently in distinguishing the studied taxa at the section and/or species levels. The findings illustrate that considerable taxonomic knowledge can be obtained by investigating the seed features of Hypericum, and the use of Scanning Electron Microscopy can reveal inconspicuous morphological affinities among species and play a role in taxonomic and systematic studies of the genus Hypericum. RESEARCH HIGHLIGHTS: Macro- and micro-morphological features of seeds of 40 Hypericum taxa from China were examined using Light and Scanning Electron Microscopy, providing the first broad study regarding seed morphology for Hypericum from China. Details and variations of seed size, shape, color, surface ornamentation, and appendages are fully presented. Seed features and their variation have important taxonomic significance at the section and/or species levels within Hypericum.
Subject(s)
Clusiaceae , Hypericum , Microscopy, Electron, Scanning , Seeds/anatomy & histology , ChinaABSTRACT
PREMISE: In recent years, Doyleales have played an important role in the discussion and exploration of seed plant relationships and the origin of angiosperms. This order comprises a diversity of recently described genera with cupule-bearing compound ovulate cones recovered from Early Cretaceous deposits in North America and Asia. Their relatively late appearance in the fossil record, stratigraphically near the appearance of angiosperms in the Early Cretaceous, has been noteworthy. Here, we report a new genus of Doyleales, Zirabia gen. nov. from the Early Jurassic of Iran, that was originally described as the ginkgophyte Karkenia. METHODS: We reinvestigated material previously assigned to Karkenia cylindrica from the Lower Jurassic of the Zirab locality, Alborz Mountains, northern Iran. RESULTS: The studied specimen features a main axis bearing helically to irregularly arranged bract-cupule complexes, each composed by a long laminar bract subtending and sheathing a cupule stalk that bears a single-seeded cupule with a dorsal protrusion. The morphological features of this taxon do not conform with those of Karkenia, and suggest affinities with Doyleales rather than Ginkgoales. Within Doyleales, this fossil has a unique combination of characters indicating that it is a new genus within the order; thus, a new combination is erected, Zirabia cylindrica. CONCLUSIONS: Our results indicate that Doyleales is significantly older than previously thought, with their stratigraphic range now extending from the Lower Jurassic to the Cretaceous. The Early Jurassic occurrence of Doyleales provides important data on the emergence of seed-enclosing structures seen in seed plants throughout the Mesozoic.
Subject(s)
Biological Evolution , Magnoliopsida , Seeds/anatomy & histology , Ginkgo biloba , FossilsABSTRACT
Domesticated opium poppy Papaver somniferum L. subsp. somniferum probably originated in the Western Mediterranean from its possible wild progenitor, Papaver somniferum L. subsp. setigerum and spread to other European regions. Seeds of opium poppy have been identified in different European regions since the Early Neolithic (from the 6th millennium cal. BC onwards) period. However, until recently, the absence of morphological identification criteria has prevented the discrimination between wild and domestic morphotypes. New morphometric approaches to distinguish modern subspecies have been proven to be applicable to waterlogged archaeological remains, opening the possibility of understanding the process of domestication of the plant in both time and space. This paper applies seed outline analyses, namely elliptic Fourier transforms, combined with size and number of cells to archaeological waterlogged Papaver seeds throughout the Neolithic period in the NW Mediterranean and the surroundings of the Alps. Furthermore, one example from the Late Bronze Age (LBA) was added to see what kind of differences appeared during the >1000 years between the end of the Neolithic and the LBA. The aim of the study is to classify the archaeological seeds as domestic or wild morphotypes and observe morphometric changes in connection to geographical and chronological patterns that can explain the spread and domestication process(es) of this important crop. A total of 295 archaeological seeds coming from 10 waterlogged sites dating between 5300-2300 cal. BC (Neolithic), and one LBA site dating to 1070 cal. BC were analysed. The results indicate the presence of seeds, similar to the wild morphotype, in the Mediterranean sites and larger seeds, similar to the domestic morphotype, in the regions surrounding the Alps. The number of cells mainly increased during the Late Neolithic (3300 to 2300 cal. BC) and, finally, in the Late Bronze Age (ca. 1050-800 cal. BC), larger, morphologically domesticated seeds are clearly predominant. A change in the shape of the seeds is only clearly visible in the LBA material. Altogether our results suggest that opium poppy seeds show no sign of domestication in the early periods of the Neolithic, despite the fact that the plant was very probably already cultivated at that time in the western Mediterranean region.
Subject(s)
Papaver , Domestication , Europe , Seeds/anatomy & histology , OpiumABSTRACT
BACKGROUND: The great species diversity of Lithocarpus is associated with interspecific fruit morphological variation, represented by acorn (AC) and enclosed receptacle (ER) fruit types. Species representing both fruit types co-occur in the same forests and share two distribution centers in southern China and southeastern Asia. The predation selection hypothesis suggests that the fruit morphological mechanical trade-off between two fruit types could represent divergent dispersal strategies under varied predation pressures. By integrating phylogenetic construction with fruit morphometric study, we tried to verify the predation selection hypothesis and elucidate the fruit type evolution of Lithocarpus, which is critical in interpreting the distribution and diversification of the genus. RESULTS: We identified the functional trade-off between the two fruit types: ER species have bigger seeds which are enclosed mainly by receptacle representing stronger physical defense; whereas the seeds of AC species are smaller and enclosed mainly by thin pericarp representing lower mechanical protection. Despite some reversals from ER back to AC, the ancestral state reconstruction in combination with thermal analysis supports the hypothesis that ER is the derived fruit type from AC-like ancestors independently across all clades. CONCLUSION: Our results support the predation selection hypothesis by verifying the mechanical trade-off between the two fruit types. We propose a divergent selection theory for the two fruit types: the seed size and mechanical defense of AC species become smaller, whereas those of ER species become larger and require more morphological modifications in the receptacle. This signified the importance of the receptacle in differentiating the two fruit types and in the fruit morphological modification through evolutionary time. We found that the ER-type species evolved independently in all clades and across varied climates from tropical to warm temperate regions. As ER fruits are products of convergent evolution, we propose to examine the predation and dispersal variation between two fruit types in the future to verify whether predation selection is the reason behind fruit type evolution of the stone oaks.
Subject(s)
Quercus , Fruit/genetics , Fruit/anatomy & histology , Phylogeny , Seeds/genetics , Seeds/anatomy & histology , ForestsABSTRACT
Copernicia alba (Arecaceae) is a palm tree regionally known as carandá that forms large populations and produces abundant fruits, an important food source for the local fauna in Brazilian wetlands. The fruits present morphological variations regarding color, shape and dimensions. In this study fruits of different shapes were collected and processed following routine techniques in plant morphology, and biochemistry analysis of endosperm. (hemicellulose) The fruits isdark, of the berry type, with partially fibrous pericarp, rich in phenolic compounds; the ruminated seed coat also contains phenols; the endosperm, formed of cells with highly thickened, not lignified hemicellulosic walls, stores xyloses, proteins and lipids. The embryo is short and straight. Xylose is the leading sugar of xylan, which can be liberated by hydrolysis with specific enzymes, such as xylanases. This sugar is of interest in several industrial sectors, such as the production of biofuels and xylitol for foods. Excepting depth of seed rumination, C. alba fruits do not have relevant differences in anatomy and classes of substances detected. The fruit yield showed differences associated with its shape, indicating the best utilization. Considering fruit anatomical features and tissue composition, we highlight that the seeds of C. alba have the potential as a new functional food source.