Layer Of Seed Coat Research Articles

Aportes a la morfología de semillas de Hibiscus cannabinus L. y ajuste de la prueba de tetrazolio para estimar viabilidad y vigor

Hibiscus cannabinus L. is an annual species cultivated for its fibers. The morphological description of the seeds of the cultivars ‘Endora’ and ‘Tainung' 1’ was broadened, a tetrazolium test procedure was adapted and adjusted, and the embryos were classified according to their viability and vigor. Cells from the seed coat layers participate in the seed coloration and ornamentation. The imbibition cap and the isthmus were identified, and their function wasanalyzed. Lipids and proteins were recognized in the mesophyll of cotyledons and the absence of areoles in the epidermis. Using the tetrazolium test, staining patterns were established to classify the seeds according to their viability. Both cultivars presented acceptable viability values. The germination test supported the proposed methodology for tetrazolium. Novel contributions are made to seed morphology, and structure-function relationships for water intake are proposed. The seeds of both cultivars share the morphological characteristics that are fundamental to the establishment of evaluation criteria in the tetrazolium biochemical test. The adapted tetrazolium viability test protocol allowed the seeds classification as either viable into three categories (high, medium, and low vigor) and non-viable seeds.

Tree Species Germination: A Comprehensive Meta-Analysis and its Implications for Pre-Sowing Treatment in Bangladesh

In Bangladesh, pre-sowing treatments significantly impact forestry species, employing water, temperature, and chemical methods to enhance seed germination. This meta-analysis, encompassing 17 research articles, emphasizes the prevalence of these treatments, with 11 studies dedicated to pre-sowing techniques and 6 as a comparison group without treatment. Findings reveal substantial heterogeneity attributed to low replications and ecological factors highlighted in articles. To address this, we recommend a balanced number of replications, considering ecological factors, to enhance research reliability in forest restoration and seed germination. Factors affecting seed germination, such as pressure, temperature, sunlight, and water stress, unfold in five stages: imbibition, respiration, light effect, mobilization of reserves, and embryo development. The seed coat layer impedes germination, and various pre-sowing treatments in Bangladesh, including mechanical, water soaking, heat, and chemical treatments, mitigate this hindrance. While this meta-analysis sheds light on ecological factors and seed performance, its limited scale underscores the need for broader studies assessing treatment effects using standardized measures.

Physical Seed Dormancy in Legumes: Molecular Advances and Perspectives.

Physical dormancy of seeds is a form of dormancy due to the presence of an impermeable seed coat layer, and it represents a feature for plants to adapt to environmental changes over an extended period of phylogenetic evolution. However, in agricultural practice, physical dormancy is problematic. because it prevents timely and uniform seed germination. Therefore, physical dormancy is an important agronomical trait to target in breeding and domestication, especially for many leguminous crops. Compared to the well-characterized physiological dormancy, research progress on physical dormancy at the molecular level has been limited until recent years, due to the lack of suitable research materials. This review focuses on the structure of seed coat, factors affecting physical dormancy, genes controlling physical dormancy, and plants suitable for studying physical dormancy at the molecular level. Our goal is to provide a plethora of information for further molecular research on physical dormancy.

Fitness and Hard Seededness of F2 and F3 Descendants of Hybridization between Herbicide-Resistant Glycine max and G. soja.

The commercial cultivation of herbicide-resistant (HR) transgenic soybeans (Glycine max L. Merr.) raises great concern that transgenes may introgress into wild soybeans (Glycine soja Sieb. et Zucc.) via pollen-mediated gene flow, which could increase the ecological risks of transgenic weed populations and threaten the genetic diversity of wild soybean. To assess the fitness of hybrids derived from transgenic HR soybean and wild soybean, the F2 and F3 descendants of crosses of the HR soybean line T14R1251-70 and two wild soybeans (LNTL and JLBC, which were collected from LiaoNing TieLing and JiLin BaiCheng, respectively), were planted along with their parents in wasteland or farmland soil, with or without weed competition. The fitness of F2 and F3 was significantly increased compared to the wild soybeans under all test conditions, and they also showed a greater competitive ability against weeds. Seeds produced by F2 and F3 were superficially similar to wild soybeans in having a hard seed coat; however, closer morphological examination revealed that the hard-seededness was lower due to the seed coat structure, specifically the presence of thicker hourglass cells in seed coat layers and lower Ca content in palisade epidermis. Hybrid descendants containing the cp4-epsps HR allele were able to complete their life cycle and produce a large number of seeds in the test conditions, which suggests that they would be able to survive in the soil beyond a single growing season, germinate, and grow under suitable conditions. Our findings indicate that the hybrid descendants of HR soybean and wild soybean may pose potential ecological risks in regions of soybean cultivation where wild soybean occurs.

Development of SNP Markers from GWAS for Selecting Seed Coat and Aleurone Layers in Brown Rice (Oryza sativa L.).

Ninety-five percent of the general nutrients in rice are concentrated in the rice bran and germ, and many nutrients such as vitamins, minerals, dietary fiber, and essential fatty acids, as well as antioxidants such as tocopherol, are lost during milling. In this study, we investigated the thickness of seed coat and aleurone layers using a 294 rice core collection, and found candidate genes related to thickness of seed coat and aleurone layers, by performing a genome wide association study (GWAS) analysis using whole genome resequencing data. Two primer pairs that can be used as high-resolution melting (HRM) markers were developed. As a result of genotyping BC2F2 individuals derived from a cross between “Samgwang” and “Seolgaeng”, and using corresponding HRM markers, it was possible to finally develop HRM markers for selecting seed coat and aleurone layer thickness. This is expected to be used as basic data for the application of gene editing using CRISPR/Cas9 technology and for establishing a breeding strategy for high eating quality rice using molecular genetic technology.

Identification of single major QTL and candidate gene(s) governing hull-less seed trait in pumpkin.

The hull-less pumpkin (Cucurbita pepo) seed does not require de-hulling before use for human consumption, as a result highly preferred by the oil, nut, and baking industries. In hull-less seeds, a single recessive gene is responsible for the absence of outer thick seed coat layers; however, the genomic region and gene(s) controlling the trait are unclear to date. In this study, four crosses attempted to derive F2 and backcross populations confirmed the single recessive gene inheritance of hull-less seed trait in populations adapted to the sub-tropical climate. The candidate genomic region for hull-less seed trait was identified through the BSA-QTLseq approach using bulks of F2:3 progenies from a cross of HP111 (hulled) and HLP36 (hull-less). A novel genomic region on chromosome 12 ranging from 1.80 to 3.86 Mb was associated with the hull-less seed trait. The re-sequencing data identified a total of 396 SNPs within this region and eight were successfully converted into polymorphic KASP assays. The genotyping of segregating F2 (n = 160) with polymorphic KASP assays resulted in a 40.3 cM partial linkage map and identified Cp_3430407 (10 cM) and Cp_3498687 (16.1 cM) as flanking markers for hull-less locus (Cphl-1). These flanking markers correspond to the 68.28 kb region in the reference genome, and the marker, Cp_3430407 successfully predicted the genotype in 93.33% of the C. pepo hull-less germplasm lines, thus can be used for marker-assisted selection in parents polymorphic for the hull-less seed trait. The Cphl-1-linked genomic region (2.06 Mb) encompasses a total of 182 genes, including secondary cell wall and lignin biosynthesis-related transcriptional factors viz., “NAC” (Cp4.1LG12g04350) and “MYB” (Cp4.1LG12g03120). These genes were differentially expressed in the seeds of hulled and hull-less genotypes, and therefore could be the potential candidate genes governing the hull-less seed trait in pumpkin.

Understanding of histological and physiological alterations in hull-less seeded pumpkin

Pumpkin seeds have great therapeutic value but remain underutilized due to its hulled character. However, a hull-less mutation revolutionized the fate of pumpkin seeds in the oil industry by omitting the decortication process. Therefore, the present research was conducted to understand the histological and physiological changes caused by this mutation in the developing seeds of pumpkin that produces the desired hull-less phenotype. In scanning electronic microscopy, a distinct five cell layered structure was observed in the seed coat of hulled (PCK-1) genotype, which was collapsed in the partially hulled (WT-2046) and the hull-less (PMK-1) genotypes. Also the seed coat layers increased continuously in hulled genotype until maturity; however, these declined after 20 DPA in the other two genotypes. Physiological studies revealed that protein, amino acid, starch and lipid content followed the same trend, but the wall components (pectin, hemicelulose, cellulose and lignin) differed significantly amongst the genotypes. The wall components increased continuously until maturity in the hulled genotype, but decreased after 20 DPA in the partially hulled and hull-less genotypes. Further, the correlation, PCA and cluster analysis also reinforced that the wall components especially the lignin was responsible in maintaining the seed coat structure in the hulled genotype and its reduction poses as a reason for the collapsed seed coat in other two genotypes. Lignin reduction was noticed at 20 DPA in the hull-less genotype and therefore, this stage can be used to identify the gene responsible for lignin synthesis in the seed coats.

Combination of electronically driven micromanipulation with laser desorption ionization mass spectrometry - The unique tool for analysis of seed coat layers and revealing the mystery of seed dormancy.

Electronically driven micromanipulation (EDM) with microscopic control was used as a novel tool for sample preparation prior to direct (matrix assisted) laser desorption/ionization mass spectrometric ((MA)LDI-MS) analysis of mature pea seed coat composition in defined layers. Microscissors were used for seed coat fragment shape adjustment, microtweezers for sample holding and "microjackhammer" Milling Pro for precise mechanical removing of cell layers in defined depths (2, 5 or 10μm). These procedures circumvent the application of embedding media or enzymatic digestion of seed coat that would complicate mass spectra interpretation (presence of matrix signals, analyte signals enhancement or attenuation) and represent alternative for 3D metabolites profiling. In addition, microinjector was used to apply a solution on intact or micropeeled seed coat surface in nano-volumes, i.e. MALDI matrix and/or lithium salt, that provide improvement of signal of sugars. Utilization of EDM enabled optimization of matrix composition on a single small fragment of seed coat overcoming thus problems with biological (seed to seed) variability. LDI-MS data were studied by multivariate statistical analysis and significant metabolites in particular layers of seed coats were identified. Normalized intensities of signals (NS) of long-chain hydroxylated fatty acids (HLFA) on intact dormant pea genotype (JI64) seed coats were significantly higher than in their counterparts treated by micropeeling confirming HLFA accumulation in outermost layers (cutin). Fatty acids distribution differences between dormant and non-dormant genotypes were explored in detail. On the other hand, NS of sugar chains and particular polyphenols were significantly higher in micropeeled seed coats of studied dormant and non-dormant genotypes than in intact seed coats. Furthermore, combination of EDM with mass spectrometry imaging (MSI) allowed vertical profiling of metabolites in hilum (a place of former attachment of seed to maternal plant) and comparison of its composition with surrounding tissues. The obtained results contribute to the understanding of relations between seed coat chemical composition and physical seed dormancy.

Incidence and Histopathological Study of Xanthomonas axonopodis pv. vesicatoria (Doidge) Dye in Chilli (Capsicum spp.) Seeds in Western Rajasthan

Bacterial leaf spot is a destructive disease in Rajasthan caused by Xanthomonas axonopodis pv. vesicatoria (Doidge) Dye. A field and market survey was conducted for the study of incidence and location. Dry seed examination of 103 seed samples of chilli (Capsicum spp.) belonging to 16 districts of Rajasthan that revealed a 10–100% incidence of Xanthomonas axonopodis pv. vesicatoria (XAV) on Tween-80 medium. Two naturally infected seed samples of chilli carrying a 100% incidence of XAV were selected and categorized into asymptomatic (06.25–94.25%), moderately discolored (01.75–42%), and heavily discolored (01.25–27.75%) seeds. The heavily discolored seeds showed shriveled, water-soaked symptoms on their surface, and on bisecting such types of infected seeds, the embryo and endosperm showed necrosis and browning. The pathogen was found confined to the outer seed coat layer, particularly at the ramnent of funiculus in a few asymptomatic seeds. In moderately discolored seeds, the pathogen was found in the seed coat and the space in between the seed coat and the endosperm. It colonized all the seed components, including embryo and endosperm, in heavily discolored seeds. The pathogen caused necrosis, the formation of lytic cavities, a reduction in cell contents, and aggregation of the bacterial cells. The pathogen was found to be extra-as well as intra-embryonic.

Brewer’s spent grains as biofuels in combustion-based energy recovery processes: Evaluation of thermo-oxidative decomposition

The high global generation of wastes and side streams from agri-food production has led to environmental impact and causes nature degradation due to their uncontrolled management. These wastes are profitable materials with significant economic value that could otherwise be exploited as new sources in the feed industry or the production of bioenergy. Among them, brewer’s spent grain (BSG) is a solid by-product generated in the beer-brewing process that consists of the barley grain husks together with parts of the pericarp and seed coat layer. Although it is rich in fibres and proteins, its main use is currently limited to animal feed or simply deposition to landfills. This study pursues the evaluation of BSGs as biofuels in energy recovery processes. For this purpose, the elemental composition, the higher heating value, the content of volatiles, fixed carbon, moisture, and ash yield along with the kinetic analysis of its decomposition during thermo-oxidative combustion were assessed. The thermo-oxidative decomposition of hemicellulose, cellulose, lignin, and char occurred in two main stages. The average apparent activation energy for Stage I was 190–200 kJ·mol−1, significantly higher than that of Stage II (100–150 kJ·mol−1). Stage I revealed a random nucleation kinetic model (Fn) and involved the volatilisation of hemicellulose and cellulose and partially lignin. Stage II, described by a three-dimensional diffusion kinetic model (D4), comprised the completion of lignin and the decomposition of char. The environmental advantage of using such residues was demonstrated with the low ash yield (in the range of 1.7–5.4%) and high calorific value between 17.8 and 19.1 MJ·kg−1. The obtained results serve as the baseline for describing the energy recovery process in a reactor that uses BSG residues as feedstock under oxidative conditions. Altogether it is pointed out the feasibility of using pelletised BSGs regardless of the malt type or mixture as a renewable source of energy in incineration plants above 500 °C.

Genetic variability of cooking time in dry beans (Phaseolus vulgaris L.) related to seed coat thickness and the cotyledon cell wall

Dry beans are an affordable, nutritious food that often require long cooking times. Storage time and conditions, growing environment, and genotype influence cooking times. Little is known about factors underlying genetic variation for cooking time. Using fast and slow cooking genotypes from four different seed types (brown, cranberry, red mottled, yellow), the objectives of this study were to (1) characterize genetic variability for cooking time across multiple soaking time points; (2) determine the roles of seed coat and cotyledon cell wall physical traits in genetic variability for cooking time; and (3) identify seed coat and cotyledon cell wall compositional differences associated with genetic variability for cooking time. Genotypes were evaluated for cooking time on unsoaked beans and beans soaked for 3, 6, 12, 18, and 24 h. Cooking times were sharply reduced after 3 h of soaking and plateaued after 6 h of soaking. Interestingly, the genotypes in each pair that cooked faster when soaked did not necessarily cook faster when unsoaked. Greater seed coat percentage, cotyledon cell wall thickness, total and insoluble whole seed dietary fiber, and insoluble cotyledon cell wall isolate were genotypic factors associated with longer cooking times of soaked beans. Thicker seed coat macrosclereid- and osteosclereid-layers were genotypic factors associated with longer cooking times of unsoaked beans. These findings suggest that cotyledon cell wall thickness and composition have a significant role in genetic variability for cooking time of soaked beans and seed coat layer thickness relates to the genetic variability for cooking time of unsoaked beans.

Diversity of metabolite accumulation patterns in inner and outer seed coats of pomegranate: exploring their relationship with genetic mechanisms of seed coat development

The expanded outer seed coat and the rigid inner seed coat of pomegranate seeds, both affect the sensory qualities of the fruit and its acceptability to consumers. Pomegranate seeds are also an appealing model for the study of seed coat differentiation and development. We conducted nontarget metabolic profiling to detect metabolites that contribute to the morphological differentiation of the seed coats along with transcriptomic profiling to unravel the genetic mechanisms underlying this process. Comparisons of metabolites in the lignin biosynthetic pathway accumulating in seed coat layers at different developmental stages revealed that monolignols, including coniferyl alcohol and sinapyl alcohol, greatly accumulated in inner seed coats and monolignol glucosides greatly accumulated in outer seed coats. Strong expression of genes involved in monolignol biosynthesis and transport might explain the spatial patterns of biosynthesis and accumulation of these metabolites. Hemicellulose constituents and flavonoids in particular accumulated in the inner seed coat, and candidate genes that might be involved in their accumulation were also identified. Genes encoding transcription factors regulating monolignol, cellulose, and hemicellulose metabolism were chosen by coexpression analysis. These results provide insights into metabolic factors influencing seed coat differentiation and a reference for studying seed coat developmental biology and pomegranate genetic improvement.

Seed coat development in explosively dispersed seeds of Cardamine hirsuta.

Seeds are dispersed by explosive coiling of the fruit valves in Cardamine hirsuta. This rapid coiling launches the small seeds on ballistic trajectories to spread over a 2 m radius around the parent plant. The seed surface interacts with both the coiling fruit valve during launch and subsequently with the air during flight. We aim to identify features of the seed surface that may contribute to these interactions by characterizing seed coat differentiation. Differentiation of the outermost seed coat layers from the outer integuments of the ovule involves dramatic cellular changes that we characterize in detail at the light and electron microscopical level including immunofluorescence and immunogold labelling. We found that the two outer integument (oi) layers of the seed coat contributed differently to the topography of the seed surface in the explosively dispersed seeds of C. hirsuta vs. the related species Arabidopsis thaliana where seed dispersal is non-explosive. The surface of A. thaliana seeds is shaped by the columella and the anticlinal cell walls of the epidermal oi2 layer. In contrast, the surface of C. hirsuta seeds is shaped by a network of prominent ridges formed by the anticlinal walls of asymmetrically thickened cells of the sub-epidermal oi1 layer, especially at the seed margin. Both the oi2 and oi1 cell layers in C. hirsuta seeds are characterized by specialized, pectin-rich cell walls that are deposited asymmetrically in the cell. The two outermost seed coat layers in C. hirsuta have distinct properties: the sub-epidermal oi1 layer determines the topography of the seed surface, while the epidermal oi2 layer accumulates mucilage. These properties are influenced by polar deposition of distinct pectin polysaccharides in the cell wall. Although the ridged seed surface formed by oi1 cell walls is associated with ballistic dispersal in C. hirsuta, it is not restricted to explosively dispersed seeds in the Brassicaceae.

Morphology and anatomy of the fruit and seed of Cananga odorata (Lam.) Hook.f. & Thomson

Abstract. Nurhayani FO, Wulandari AS, Suharsi TK. 2019. Morphology and anatomy of the fruit and seed of Cananga odorata (Lam.) Hook.f. & Thomson. Biodiversitas 20: 3199-3206. Cananga odorata (Lam.) Hook.f. & Thomson is one of the Annonaceae family which has high benefits for humans such as constructions, furniture, cosmetics, perfumes, and traditional medicines. The planting efforts were needed to support the existence of these plants. These plants have low regeneration and germination. The morphology and anatomy of fruit and seed could enhance the understanding of the reproductive biology in the species. There is little information about the morphology and anatomy of fruit and seed of C. odorata var. odorata forma genuina. The aim of this study is to understand the morphology and anatomy of fruit and seed of C. odorata. The morphologic description was made from the analysis of the fresh fruits and seeds. The anatomical description was made from the analysis of permanent slides with longitudinal sections of the fruits and seeds. The samples were fixed, dehydrated, alcoholized, embedding in paraffin, and stained with safranin-fast green. Data analysis consists of the morphological observation (shape, color, size and the number of seeds per fruits) and the anatomical observation (the pericarp layers of fruit, the seed coat layers, and the structure in the seed). The fruit of C. odorata var. odorata forma genuina was fleshy, ovoid or obovoid, 0.98-2.75 cm long, 0.42-1.63 cm in diameter, and contain 1-12 seeds. The seeds were pale brown, flattened, ovoid, and hard. The fruit anatomy showed that the pericarp layers derived from parenchymatous cells and differentiated into three zones, i.e. exocarp, mesocarp, and endocarp. The seed has ruminated endosperm with irregular folds. The seed coat was divided into three integuments, i.e. outer, middle, and inner integument. The information about the fruit and seed anatomy of C. odorata var. odorata forma genuina might enhance the understanding of future studies regarding natural reproduction and conservation programs with generative propagation.

Programmed cell death in soybean seed coats

Seed coat is the tissue which establishes an interface between the seed inner tissues and external environment. Our group has shown that cowpea seed coat undergoes coordinated events of programmed cell death (PCD) during development. In relation to germinating seed coats, little is known on PCD events. The goal here was to investigate the biochemical aspects of germinating soybean seed coat, focusing on proteolytic activities related to PCD. In gel and in solution activity profiles of quiescent and germinating seed coat extracts revealed a complex pattern of caspase- and metacaspase-like cysteine protease activities. Trypsin inhibitor and reserve proteins were revealed as potential substrates for these proteases. A pancaspase inhibitor (z-VAD-CHO) affected the radicle length of seeds germinated under its presence. Ultrastructural analysis showed the absence of cell organelles in all seed coat layers after imbibition, while oligonucleosome fragments peaked at 72 h after imbibition (HAI). Altogether, the data suggest the presence of biochemical PCD hallmarks in germinating soybean seed coat and point to the involvement of the detected protease activities in processes such as reserve protein mobilization and weakening of seed coat.

ERECTA receptor-kinases play a key role in the appropriate timing of seed germination under changing salinity.

Appropriate timing of seed germination is crucial for the survival and propagation of plants, and for crop yield, especially in environments prone to salinity or drought. However, the exact mechanisms by which seeds perceive changes in soil conditions and integrate them to trigger germination remain elusive, especially once the seeds are non-dormant. In this study, we determined that the Arabidopsis ERECTA (ER), ERECTA-LIKE1 (ERL1), and ERECTA-LIKE2 (ERL2) leucine-rich-repeat receptor-like kinases regulate seed germination and its sensitivity to changes in salt and osmotic stress levels. Loss of ER alone, or in combination with ERL1 and/or ERL2, slows down the initiation of germination and its progression to completion, or arrests it altogether under saline conditions, until better conditions return. This function is maternally controlled via the tissues surrounding the embryo, with a primary role being played by the properties of the seed coat and its mucilage. These relate to both seed-coat expansion and subsequent differentiation and to salinity-dependent interactions between the mucilage, subtending seed coat layers and seed interior in the germinating seed. Salt-hypersensitive er105, er105 erl1.2, er105 erl2.1 and triple-mutant seeds also exhibit increased sensitivity to exogenous ABA during germination, and under salinity show an enhanced up-regulation of the germination repressors and inducers of dormancy ABA-insensitive-3, ABA-insensitive-5, DELLA-encoding RGL2, and Delay-Of-Germination-1. These findings reveal a novel role of the ERECTA receptor-kinases in the sensing of conditions at the seed surface and the integration of developmental, dormancy and stress signalling pathways in seeds. They also open novel avenues for the genetic improvement of plant adaptation to changing drought and salinity patterns.

Refining of the egusi locus in watermelon using KASP assays

Egusi watermelon (Citrullus mucosospermus), a close relative of sweet watermelon, is an economically important crop grown in many West African countries for its protein and lipid rich edible seeds. Egusi watermelon seeds have a thick, fleshy mucilaginous seed coat layer surrounding the seed coat which is unique to egusi watermelon. The egusi seed trait is controlled by a single recessive Mendelian locus, eg, located on chromosome 6 from 6.75 Mb to 11.03 Mb. This region is 4.28 Mb wide and contains 241 candidate genes. The region lacks adequate markers for fine mapping and for marker-assisted selection (MAS) of the egusi trait. In this study, we used QTL-seq to validate the position of the eg locus and to identify SNP markers to refine the locus. A genomic region associated with the egusi trait was confirmed on chromosome 6 from 5.25 Mb to 7.85 Mb partially overlapping the previously mapped eg locus. SNPs identified from QTL-seq were used to design Kompetitive Allele Specific PCR (KASP™) assays for refining the eg locus. The eg locus was remapped at 86.3 cM on the genetic map, co-segregating with marker UGA6_7026576. The refined eg locus is 398.25 Kb long, extending from 6.95 Mb to 7.35 Mb, containing 30 candidate genes. Additional validation of the markers in a diversity panel and the validation population identified marker UGA6_7026576 as associated with the egusi phenotype and useful for MAS.

Scarification of Altaic Flax Seeds With High-Power UV Radiation Generated by Plasma of Nanosecond Electric Discharges

This paper describes an investigation of effect of high-power UV-radiation plasma, generated by electric discharges, on germination rate of Altaic flax seeds (Linum altaicum) . It was found that UV-radiation scarifies flax seeds by means of cracks formation in the seeds’ coat. The cracks shorten moisture penetration time to a seed bud thus twice increasing the germination rate. It is found that the germination rate function has the three-stage character; the velocity-growth function has the view of three pulses, which separates the seeds into three subgroups. Division of the group into subgroups is stipulated by the probabilistic nature of the cracks formation. The number of subgroups is equal to the number of layers +1. We calculated average times of natural moisture penetration through the flax seed coat layers: $T_{s} =11.8$ h through the spermoderm and $T_{e} =17.7$ h through the endosperm. It is possible that scarification of the flax seed coats can shorten the germination time for these times. We also noted that some seeds could die due to the effect of high-power UV radiation. So, it is necessary to find more sparing regimes of the seeds UV irradiation.

Phenolics levels in different parts of common buckwheat (Fagopyrum esculentum) achenes

Common buckwheat achenes have high antioxidant activity due to their high phenol and especially flavonoid content. In general, the highest phenol contents in seeds is related to the seed coat layers. However, there is insufficient information about the composition of the individual parts of the buckwheat achene.The aim of this study was to determine the distribution and content of selected phenols within the individual parts of buckwheat achenes as well as the influence of soaking before hulling had on the phenol content.The seed coat was the part with the widest range of detected compounds, and also with the highest total content of phenolics from all groat parts. The seed coat was especially rich in epicatechin (257.60 mg/kg), procyanidin B2 (118.6 mg/kg), and epicatechin gallate (61.27 mg/kg). The embryo axis with the cotyledons is rich in rutin (283.37 mg/kg) and catechin (161.41 mg/kg). Contrary to groats, vanillic acid, vanillin, vitexin, quercitrin, and protocatechuic acid were detected in the buckwheat hulls. One-hour soaking of the achenes in tap water before dehulling caused a significant decrease (37%) in the content of phenolic compounds. The variety Špačinská had the highest level of identified phenolic compounds in the buckwheat hulls.

Flower vascularization and fruit developmental anatomy of quinoa (Chenpodium quinoa Willd) Amaranthaceae

The floral anatomical structural and developmental features of seeds and fruits of quinoa (Chenpodium quinoa Willd) cv. Hualhuas were studied using light microscope with the purpose to elucidate their structure and to contribute ecological studies of the species. The plants produce panicle inflorescences having hermaphrodite and pistillate flowers. The hermaphrodite flower possesses: 5 imbricate sepals; 5 antisepalous stamens; its filaments extend laterally forming a ring of nectariferous tissue surrounding the ovary having modified stomata. The gynoecium is bicarpellate with unilocular ovary having a single campylotropus ovule. The basal part of the ovary contains two dorsal carpellary bundles one is small towards the posterior side the other is large towards the anterior side. Whereas the ventral carpellary bundles of the two carpels occurring in the center of the ovary base and consist the vascular supply of the ovule. The dorsal posterior bundle terminates with the appearance of the locule. The ovule attach with the basal placenta on the anterior side of the ovary. The posterior carpel is sterile and reduced whereas the anterior one is fertile. The nutrients movement into the seed takes place through the high selectivity phloem elements embedded in the vascular strand of the funiculus. The collapsed outer layer of the pericarp in mature fruit could reshaped and regain turgor pressure after soaking in water, this may help for rapid germination. Although quinoa has thin seed coat layers however it have thick cell walls could maintain the moisture of embryo and perisperm and increase seed hardness as response to the arid habitats.