Seed Coat Surface Research Articles

Seed pretreatment using design of engineering approach for regulating <em>Humulus lupulus</em> seed germination in different media

Humulus lupulus, a plant of commercial benefit, has been widely explored for its therapeutic applications. Plant propagation via seeds is one of the major challenges due to seed dormancy and low germination. The physical dormancy of the seed caused by a hard seed coat makes seeds impervious to water. Different types of methods have been reported to break the seed dormancy. The present study emphasizes the optimized chemical method of seed pretreatment for regulating the germination efficiency in three different media namely, Murashige and Skoog (MS), Hoagland’s media and Leafy 200®. The study explores the interaction between two variables viz., acid treatment time and concentration of sulphuric acid, on germination of Humulus lupulus seeds using the Design of Experiment (DOE) approach. The results showed a higher germination rate in MS media and Leafy200® media (100%) seed germination percentage with respect to Hoagland’s media. The result demonstrates the synergistic role of seed pretreatment and media on the seed germination efficiency. The scanning electron microscopy (SEM) analysis of the seeds pretreated with acid revealed small perforations on the seed coat ranging between 5-15 µm. Furthermore, the elemental analysis of the seed coat surface by Energy Dispersive X-ray (EDX) revealed a substantial decrease in carbon and oxygen (%) and the presence of calcium, magnesium, and sulfur. The results indicate the acid hydrolysis of organic constituents on the seed surface enabling changes in seed porosity. Additionally, factors such as pretreatment and media play a pivotal role in regulating seed germination.

Study of the Effects of Plasma Pretreatment on the Microstructure of Peanuts

In this study, cold plasma treatments are employed to modify peanuts. This study systematically investigates the effects of various plasma treatment conditions, including power, duration, and gas type, on the microstructure of peanut seed coats and embryos. Observations under a scanning electron microscope (SEM) reveal that as plasma treatment power increases from 100 W to 500 W, the etching level of peanut seed coats significantly intensifies, surface roughness deepens, and concavities become more pronounced. Additionally, micro-pores on the seed coat gradually enlarge and form cracks. Specifically, when the plasma treatment is set at 200 W for 60 s, the oxygen (O2) treatment group shows interconnected cracks on the peanut seed coat surface, with lipid particles exuding and protein particles and polymers decomposing. In contrast, the helium (He) treatment group displays clear cell structures and deep grooves, with no noticeable lipid particles exuding around surface cracks. The argon (Ar) treatment group exhibits a distinct rectangular cell structure with clear boundaries, and although surface cracks form, only a few protein particles escape from the cracks. The embryo surface structure becomes looser after plasma treatment, leading to the disintegration of lipid particles, protein particles, and polymers, affecting the fusion and migration of large and small lipid bodies within the peanut’s internal structure. Increasing treatment duration intensifies the etching phenomenon, resulting in more lipid particles exuding, which indicates a positive correlation between lipid particles exuding and treatment duration. This study sheds light on the mechanisms underlying changes in peanut microstructure due to cold plasma treatment, providing scientific evidence for improving peanut quality, enhancing oil extraction efficiency, and optimizing food processing techniques.

Assessing the influence of non-thermal plasma treatment on sprouting of mosaic yard long beans (Vigna unguiculata)

This study examined the impact of non-thermal plasma (NTP) treatment on the germination of mosaic yard long beans (MYLB) (Vigna unguiculata). The NTP discharge utilized 5.01 W of power and had an estimated electron density of 2.5 × 1011 cm−3. Optical emission spectra analysis confirmed the generation of nitrogen ions using the dielectric barrier discharge system. Seeds exposed to NTP for varying durations exhibited enhanced germination rates and higher vigor, with the highest percentage observed for 120 s of treatment. Seeds treated for 60 and 120 s displayed faster and more synchronized germination based on the Mean Germination Time and Coefficient of Velocity of Germination values. The NTP treatment resulted in mass loss in the seeds, with the greatest loss occurring after 120 s of treatment. NTP-treated seeds demonstrated improved water uptake capacity compared to untreated seeds. Water contact angle measurements indicated a shift from hydrophobic to hydrophilic behavior in NTP-treated seeds, indicating enhanced surface wettability. Scanning electron microscopy analysis revealed erosion and roughening of the seed coat following NTP treatment. These findings suggest that NTP treatment enhances the germination performance of MYLB by promoting faster and more uniform germination, improving water uptake capacity, and modifying the seed coat surface.

GoSAMTs are required for pectin methyl-esterification and mucilage release in seed coat epidermal cells.

GoSAMTs play a role in the methylation of polysaccharides synthesized by the Golgi. Pectin homogalacturonan (HG) methyl-esterification is essential for the proper function of this polysaccharide in cell walls. In order to better understand the role of GoSAMTs in HG biosynthesis, we analyzed mucilage methyl-esterification in gosamt mutants. To determine the function of GoSAMT1 and GoSAMT2 in HG methyl-esterification we utilized epidermal cells of seed coats, as these structures produce mucilage, which is a pectic matrix. We evaluated differences in seed surface morphology and quantified mucilage release. We measured methanol release, and used antibodies and confocal microscopy to analyze HG methyl-esterification in mucilage. We observed morphological differences on the seed surface and delayed, uneven mucilage release in gosamt1-1gosamt2-1 double mutants. We also found changes in the distal wall length indicating abnormal cell wall breakage in this double mutant. Using methanol release and immunolabeling, we confirmed that GoSAMT1 and GoSAMT2 are involved in HG methyl-esterification in mucilage. However, we did not find evidence of decreasing HG in the gosamt mutants. Confocal microscopy analyses detected different patterns in the adherent mucilage and a greater number of low-methyl-esterified domains near the seed coat surface, which correlates with a greater number of "egg-box" structures in this region. We also detected a shift in the partitioning between the Rhamnogalacturonan-I soluble and adherent layers of the double mutant, which correlated with increased amounts of arabinose and arabinogalactan-protein in the adherent mucilage. The results show that the HG synthesized in gosamt mutant plants is less methyl esterified, resulting in more egg-box structures, which stiffen the cell walls in epidermal cells and change the rheological properties of the seed surface. The increased amounts of arabinose and arabinogalactan-protein in adherent mucilage, also suggests that compensation mechanisms were triggered in the gosamt mutants.

Seed choice in ground beetles is driven by surface-derived hydrocarbons

Ground beetles (Coleoptera: Carabidae) are among the most prevalent biological agents in temperate agroecosystems. Numerous species function as omnivorous predators, feeding on both pests and weed seeds, yet the sensory ecology of seed perception in omnivorous carabids remains poorly understood. Here, we explore the sensory mechanisms of seed detection and discrimination in four species of omnivorous carabids: Poecilus corvus, Pterostichus melanarius, Harpalus amputatus, and Amara littoralis. Sensory manipulations and multiple-choice seed feeding bioassays showed olfactory perception of seed volatiles as the primary mechanism used by omnivorous carabids to detect and distinguish among seeds of Brassica napus, Sinapis arvensis, and Thlaspi arvense (Brassicaceae). Seed preferences differed among carabid species tested, but the choice of desirable seed species was generally guided by the olfactory perception of long chain hydrocarbons derived from the seed coat surface. These olfactory seed cues were essential for seed detection and discrimination processes to unfold. Disabling the olfactory appendages (antennae and palps) of carabid beetles by ablation left them unable to make accurate seed choices compared to intact beetles.

Re-establishment of Sileneneglecta Ten. (Caryophyllaceae) with taxonomic notes on some related taxa.

Sileneneglecta has been misunderstood and confused with S.nocturna, although several morphological characters (petal shape, calyx indumentum, hairiness of stamen filaments, seed size, seed-coat surface and shape) allow separation of these species. Moreover, S.mutabilis (which has been considered conspecific with S.neglecta) and S.martinolii (an alleged endemic species to south-western Sardinia) are considered here as taxonomic synonyms of S.nocturna and S.neglecta, respectively. These taxonomic conclusions are strongly supported by multivariate morphometric analyses of 21 characters.

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.

The Effect of Non-Thermal Atmospheric Pressure Plasma Treatment of Wheat Seeds on Germination Parameters and α-Amylase Enzyme Activity

This contribution presents the results of a study of the germination rate and growth parameters of wheat seeds after atmospheric pressure surface coplanar dielectric barrier discharge (DBD) plasma treatment. The germination rate and biometric parameters such as the root, shoot length, mass of the seedlings, and the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula> -amylase enzyme activity were studied at different plasma exposure time. The seed coat surface wettability and morphology were determined by apparent contact angle measurement and scanning electron microscope (SEM) analysis. Seed surface disinfection and the presence of filamentous fungi have also been investigated at different discharge parameters. It is shown that the optimal plasma treatment duration for increasing the growth parameters and enhancing the enzymatic activity is 5–15 s. It was found that the longer plasma exposure requires complete sterilization of the seed surface from pathogens, compared to the optimal treatment time for high germination. Based on the obtained results, the possible mechanisms of the positive effect of plasma treatment on the enhanced germination of wheat seeds are discussed.

Effect of seed coat microstructure and lipid composition on the hydration behavior and kinetics of two red bean (Phaseolus vulgaris L.) varieties.

Bean hydration is a crucial, yet complex process affected both by inherent bean properties (intrinsic) and properties of the soak medium (extrinsic) whose relationship with hydration kinetics are not clear. This work investigated the effect of temperature (30-80°C) on the hydration behavior and kinetics of two commonly consumed Phaseolus vulgaris L. beans-red kidney and small red beans. Both beans have similar morphology (except size), chemical composition and seed coat surface structure but, surprisingly, their hydration behaviors differed markedly. Small red hydration followed a sigmoidal shape (to 70°C) with a prominent lag phase at 30-40°C, while fast hydrating red kidney beans followed a downward concave shape, suggesting different mechanisms of water uptake. The hydration behaviors for red kidney and small red beans were modeled using Peleg (R2 ≥0.97) and sigmoidal (R2 ≥0.99) models, respectively. Water uptake rate increased, while equilibrium moisture content decreased for both bean varieties with increasing temperature. A simplified model was developed for small red beans which can predict hydration as a function of temperature and time with good accuracy ( , R2 =0.99, RMSE=4.5). Microscopic examination of cross sections of seed coats showed nearly double parenchyma layer thickness in small red bean and seed coat lipid analysis showed significantly higher proportion of saturated fatty acids which, together, may be responsible for slower water uptake observed in small red beans. PRACTICAL APPLICATION: Hydration is the crucial stage in dry bean processing, which precedes other processes like cooking, extraction, fermentation, sprouting, and consumption. Industrial bean processing is still slow and batch process and needs improvement. This work shows the effect of various bean properties and soaking medium temperature on the hydration behavior of two commonly consumed red beans. The work also modeled the hydration kinetics of two Phaseolus vulgaris L. beans which can be adopted by bean processors for process design and optimization.

A conserved cellular mechanism for cotton fibre diameter and length control

Abstract Highly polarized cotton fibre cells that develop from the seed coat surface are the foundation of a multi-billion-dollar international textile industry. The unicellular trichoblast emerges as a hemispherical bulge that is efficiently converted to a narrower and elongated shape that extends for about 2 weeks before transitioning into a cellulose-generating machine. The polarized elongation phase employs an evolutionarily conserved microtubule-cellulose synthase control module that patterns the cell wall and enables highly anisotropic diffuse growth. As the multi-scale interactions and feedback controls among cytoskeletal systems, morphologically potent cell wall properties, and a changing cell geometry are uncovered, opportunities emerge to engineer architectural traits. However, in cotton, such efforts are hampered by insufficient knowledge about the underlying control mechanisms. For example, fibre diameter is an important trait that is determined during the earliest stages of development, but the basic growth mode and the mechanisms by which cytoskeletal and cell wall systems mediate fibre tapering are not known. This paper combines multiparametric and multiscale fibre phenotyping and finite element computational modelling of a growing cell to discover an evolutionarily conserved tapering mechanism. The actin network interconverts between two distinct longitudinal organizations that broadly distributes organelles and likely enables matrix secretion patterns that maintain cell wall thickness during growth. Based on plausible finite element models and quantitative analyses of the microtubule cytoskeleton, tapering and anisotropic growth is programmed by a constricting apical microtubule depletion zone and highly aligned microtubules along the fibre shaft. The finite element model points to a central role for tensile forces in the cell wall to dictate the densities and orientations of morphologically potent microtubules that pattern the cell wall.

Taxonomic Significance of Seed Morphology in Veronica L. (Plantaginaceae) Species from Central Europe.

In this study, 1159 seeds of 29 Central European species of the genus Veronica were analyzed based on scanning electron microscopy images. The species belonged to nine subgenera: Beccabunga, Chamaedrys, Cochlidiosperma, Pellidosperma, Pentasepalae, Pocilla, Pseudolysimachium, Stenocarpon and Veronica, following the newest phylogenetic classification of the genus. Nine measured characteristics of seeds and nine ratios were analyzed statistically using ANOVA followed by post hoc testing, cluster analysis and discriminant analysis. In most cases, the results were not congruent with the contemporary classification of the genus. Examinations of qualitative seed features by scanning electron microscopy included the cochlidiospermous or discoid seed type, the seed shape, the general sculpture of the seed coat surface, the sculpture of anticlinal and periclinal walls and some species-specific traits such as the presence of the epidermal appendix. All these features, apart from seed shape, were useful to distinguish all subgenera and some species within subgenera: Beccabunga, Chamaedrys, Pellidosperma, Pocilla (only V. filiformis) and Veronica. The identification key based on the seed micromorphological features was prepared.

Application of multivariate analysis to identify relationships among useful agronomic characters of cowpea and differentiation of cultivars for vegetable and grain uses

Background. Сowpea (Vigna unguiculata (L.) Walp.) is a thermophilic crop; in most countries it is grown for grain and vegetable uses. Positive results of open-field cowpea production in the southern regions of Russia and the possibility of its cultivation on infertile soils in hot and dry climate imply the need to develop new cultivars suitable for wider introduction into Russian agriculture. It is of paramount importance for cowpea breeders to know the patterns of variability in the relationships among agronomic traits and their characteristics in cultivars grown for different uses (grain and vegetable). Besides, acceleration of the breeding process to a large extent depends on the knowledge of the traits that make it possible to differentiate the source material according to its intended purpose.Materials and methods. For three years, 315 cowpea accessions of various origin from the VIR collection were studied in Astrakhan Province, Russia. Eight useful agronomic characters were examined. The variability and relationships of these characters were assessed in cultivars grown for grain and vegetable purposes using multivariate statistical analyses.Results and discussion. The characters that differentiate grain and vegetable cowpea accessions were identified: the type of seed coat surface, the presence of fiber in ventral and dorsal pod sutures and a sclerenchyma layer in pods valves, and pod length. Discriminant functions were calculated for identification and classification of accessions according to their grain and forage uses. The character (presence of depressions or longitudinal striae on the seed coat surface) diagnosing vegetable cowpea cultivars was pinpointed. Characters associated with high seed yield were identified. For grain cultivars such character is the weight of 1000 seeds, while for vegetable cultivars it is a large-seeded and long-fruit pod.

Seed morphology, anatomy and histochemistry in two Mexican species of Mimosa (Leguminosae, mimosoid clade)

Mimosa species have biological and ecological importance, they exhibit advantages that make them competitive candidates for ecological restoration; considering that the seed is essential for the establishment of the species, it is required to characterize the seeds morphologically and anatomically, especially those that come from multipurpose plants like the mimosas are. The objective was to study the morphology, anatomy and histochemistry of the seeds of Mimosa aculeaticarpa and M. luisana, with the aim of better contextualising and understanding their ecological implications of the fact that the seed is the fundamental stage for the propagation and perpetuation of the species. The morpho-anatomical study was performed by light microscopy (LM) and scanning electron microscopy (SEM), histochemistry was used for detection of cuticle, lignified cell walls and starches. The seeds of M. aculeaticarpa are ovoid and those of M. luisana are spheroid to ellipsoid. In both species the seed coat shows fracture lines, in M. aculeaticarpa var. aculeaticarpa they are limited to the pleurogram, lens, hilum and micropyle regions, while in M. luisana they occupy the entire surface of the seed. Seed coat surface in M. aculeaticarpa var. aculeaticarpa is simple reticulate and each space that is enclosed by the reticulation is densely rugose, while in M. luisana it only has an irregularly rugose pattern. The micropyle is ellipsoid and protruding (M. aculeaticarpa) or punctiform and sunken (M. luisana). Anatomically, there is a cuticle; the seed coat of M. aculeaticarpa has only macrosclereids, while that of M. luisana also has a layer of osteosclereids. The anatomical characters make it possible to distinguish between the two species. The morpho-anatomical characters prevent initial germination, increase the longevity of the seeds and are the probable cause of impermeability.

Changes in Microstructure, Germination, Sprout Growth, Phytochemical and Microbial Quality of Ultrasonication Treated Adzuki Bean Seeds

Sprout is a nutritious ready-to-eat vegetable. In this study, we examined the effects of ultrasonication treatments (treated with 28, 40 or 80 kHz frequency for 10 min at 25 °C) on the changes in microstructure, seed hydration and germination, sprout growth, sprout quality, and microbial load of two adzuki bean (Vigna angularis) varieties (Kaohsiung 8 and Kaohsiung 10). The results indicated that the ultrasonication at 40 kHz or 80 kHz improved seed hydration and enhanced germination; this is linked to the ultrasound-induced microstructure changes in the hilum and seed coat surface of treated seeds. The ultrasonication-increased sprout growth and yield were possibly attributable to the increased α-amylase activity during germination. Ultrasonication also improved total polyphenols, total flavonoids, and total saponins contents and further enhanced the anti-oxidative activities (FRAP and DPPH) of produce sprouts. The results further indicated that the 40 kHz or 80 kHz treatment decreased microbial loads of treated sprouts to an acceptable level; therefore, these two treatments can be used for germination improvement and an effective microbial control treatment for adzuki bean sprout production.

&lt;strong&gt;Taxonomic application of macro and micro morphological characters of seeds in &lt;em&gt;Astragalus&lt;/em&gt; L. (Galegeae, Fabaceae) in India&lt;/strong&gt;

Due to large size and enormous morphological plasticity, the taxonomy of the genus Astragalus is very complex and challenging. The identification and grouping of species chiefly based on macromorphological characters become sometimes difficult in the genus. In the present study, the micromorphology of the seeds of 30 species belonging to 14 sections of Astragalus from India has been examined applying scanning electron microscopy (SEM) along with light microscopy (LM) to evaluate their role in identification and classification. Attention was paid to colour, shape, size and surface of seeds. The overall size of the seeds ranges from 1.5–3.2 × 0.8–2.2 mm. The shape of the seeds is cordiform, deltoid, mitiform, orbicular, ovoid and reniform. The colour of seeds varies from brown to blackish-brown to black. Papillose, reticulate, ribbed, rugulate and stellate patterns were observed on the seed coat surface (spermoderm) among different species. The study reveals that the seed coat ornamentations have evolved differently among species and do not support the subgeneric and sectional divisions of the genus. However, they add an additional feature to the individual species, which may help in identification in combination with other macro-morphological features.

Seed morphology in the genus Iris (Iridaceae) from Russia

The genus Iris in Russia is represented by 41 species. Four species are endemic, 11 are included in the Red Data Book of the Russian Federation and 30 have different regional conservation status. The presented results of the study of the morphology of seeds and of seed coat surface morphology in 40 species from the genus Iris growing in Russia were obtained mainly using light and scanning electron microscopy. Seed shape is round, ovate, oblong or pear‑shaped, with the exception for I. psammocola, in which it is club‑shaped. The smallest seeds in the studied species belong to I. ruthenicaand I. uniflora. Morphometric data lead to interesting conclusions regarding the taxonomic relations between some species. For example, the species currently considered as synonyms, e.g., I. biglumisand I. pallasii in I. lactea, and I. maackii in I. pseudacorus, are found different concerning seed morphology. On the other hand, the taxonomically well distinct species such as I. halophila and I. pseudonotha share similar seed morphology. A study of the morphological characteristics of the seed coat surface in 40 species of the genus Iris made it possible to compile an atlas for determining species in the genus Iris in Russia.

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

Background: This paper investigates whether the fruit and seed micromorphology of eight Turkish Iberis (Brassicaceae) species can be used as a further aid in their taxonomic delimitation.&#x0D; Questions: Are the micro-morphological characters of the fruits and seeds of Iberis useful to support the taxonomic delimitation of its species?&#x0D; Studied species / data description /Mathematical model: The eight species of Iberis present in Turkey were examined. The fruit and seed characteristics were obtained and statistical analysis was performed using UPGMA.&#x0D; Study site and dates: Fifteen localities in Turkey, from 2015 to 2019.&#x0D; Methods: Samples of fruit and seed of eight species of Iberis were collected, stored, and later measured and described with aid of light and scanning electron microscopies.&#x0D; Results: All eight species had different fruit and seed characters; particularly differing from each other with respect to fruit and seed size, seed shape and seed ornamentation. Two fruit ornamentation types were evident, smooth and striated. The seed coat surface were separated into three types: reticulate, reticulate-rugose and reticulate-papillate, being reticulate the most common. Further differences were noted for the seed surface epidermal structures, notably species had rectangular, tetragonal, or pentagonal patterning. An identification key was constructed based on a similarity analysis.&#x0D; Conclusions: Fruit morphology, seed dimensions, colour, and epidermal cell patterning are useful microcharacters that enabled species-level determinations in the Iberis species sampled.

Seeds quality of the domestic millet (Panicum virgatum L.) depending on the scarification mode

The aim of the research is determination of millet seed scarification efficiency depending on the modes – the amount of seeds surface removal. Scarification implies mechanical damage to the solid seed coat surface and its partial removal is applied to increase the intensity of seed germination. Studies oo implying this method on the millet seeds of the rod-shaped millet have shown that the seeds germination energy and sprouting significantly increase. On average for 15 experiments, these indicators increased by 7 % compared to the control – without scarification. A comprehensive study of the effect of scarification and vegetation years on germination energy and seed germination revealed that both the vegetation years and scarification influence these parameters. The share of factors influence on the seeds germination showed that the "vegetation year" factor was the dominant and made 70.9 %, the impact of scarification factor made only 6.9 %. The seeds quality in both control and scarification variants varied significantly depending on the vegetation years of the millet. The highest germination energy and sprouting were in the seeds of the seventh year, the lowest – the fourth year of the crop vegetation. To investigate the impact of scarification on the seeds quality, a series of one-factor experiments were conducted in which the seeds of one batch were used. It is found that scarification with removing 2.8–8.8 % of the seed coat, provided a significant increase in seed germination compared to the control (without scarification). Removal of 8.8 % of the seed coat surface provided 9 % increase in germination energy and 6 % in sprouting increase; removal of 2.8 % of the surface provided germination energy increased by 11 % and sprouting increase by 8 %. The impact of the scarification factor on the germination energy and sprouting was significant and amounted to 50.0 and 84.0 %, respectively. The application of scarification of the millet seed provides a reliable increase in its germination energy and sprouting, but this method does not solve the problem of reducing the seeds biological dormancy, so it is advisable to continue the study on the nature of the seed dormancy in order to clarify tme possibility of managing this phenomenon and improve the technology of obtaining sufficient amount of high germination seeds. Key words: sprouting, germination energy, scarification, seed coat, seed mass.

Significance of seed trichome micro-morphology in systematic treatment of Abelmoschus-Hibiscus complex

Indian sub-continent is rich in genetic diversity of various species of genus Abelmoschus and Hibiscus. Several of these species exist in wild, semi-wild and cultivated forms due to favorable eco-geographical conditions. Seed morphology (especially trichome structure) of Malvaceae members is known to be diverse, but variation patterns have never been critically studied in these complex genera. In the present paper usefulness of this important character for the generic differentiation between Abelmoschus (13 species) and Hibiscus (10 species) using scanning electron microscopy of seed has been described. Primary generic differentiation has been derived using basic seed trichome morphology i.e. unicellular (un-fused) and multi-cellular (fused) which was spiral or non–spiral, spread evenly or localized in all the studied taxa. The presence of unicellular and un-fused trichomes on seed coat surface in the Abelmoschus species provides an additional and significant micro-morphological differentiation to delineate the boundaries between genus Abelmoschus and Hibiscus.

Effect of Physical Treatments on the Promotion of Seed Germination in Green and Giant Foxtails

The difficulty of breaking seed dormancy in Setaria (foxtail) species presents a problem in using them as model plants. In the present study, we observed the structure of the seed coat surface of two Setaria species, the green foxtail (Setaria viridis) and the giant foxtail (Setaria faberi), using an electron microscope. In addition, we tested the effects of physical treatment on Setaria seeds using four treatments: (1) Removing the outer seed coat, (2) removing the outer seed coat + mechanical scarification of the inner seed coat (the seeds were scarified using sand-paper with grit 350-2000), (3) removing the outer and inner seed coat and (4) No treatment (control). During the observation using electron microscope, we found a structure that was supposed to repel water (which is called the ‘lotus effect’). We found that seed germination in Setaria species can be induced by removing the outer seed coat along with mechanical scarification of the inner seed coat (second treatment) as well as by removing the outer and inner seed coat (third treatment), whereas seed germination was not observed after removing only the outer seed coat and no treatment.