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Seed and fruit mucilage is composed of three types of polysaccharides—pectins, cellulose, and hemicelluloses—and demonstrates adhesive properties after hydration. One of the important functions of the mucilage is to enable seeds to attach to diverse natural surfaces. Due to its adhesive properties, which increase during dehydration, the diaspore can be anchored to the substrate (soil) or attached to an animal’s body and dispersed over varied distances. After complete desiccation, the mucilage envelope forms a thin transparent layer around the diaspore creating a strong bond to the substrate. In the present study, we examined the mucilaginous seeds of six different plant taxa (from genera Linum, Lepidium, Ocimum, Salvia and Plantago) and addressed two main questions: (1) How strong is the adhesive bond of the dried mucilage envelope? and (2) What are the differences in adhesion between different mucilage types? Generally, the dried mucilage envelope revealed strong adhesive properties. Some differences between mucilage types were observed, particularly in relation to adhesive force (Fad) whose maximal values varied from 0.58 to 6.22 N. The highest adhesion force was revealed in the cellulose mucilage of Ocimum basilicum. However, mucilage lacking cellulose fibrils, such as that of Plantago ovata, also demonstrated high values of adhesion force with a maximum close to 5.74 N. The adhesion strength, calculated as force per unit contact area (Fad/A0), was comparable between studied taxa. Obtained results demonstrated (1) that the strength of mucilage adhesive bonds strongly surpasses the requirements necessary for epizoochory and (2) that seed mucilage has a high potential as a nontoxic, natural substance that can be used in water-based glues.

Myxodiaspory (formation of mucilage envelope around seeds and fruits) is a common adaptation to dry habitats known in many families of Angiosperms. The mucilage envelope of some seeds seems to be also a unique morphological adaptation which protects myxospermatic diaspores while passing through the bird’s digestive system. To evaluate the protective potential of mucilage, we fed the diaspores of seven plant species (representing three different mucilage types and three species of non-mucilaginous plants) to pigeons, Columba livia domestica. Twenty-four hours later, we collected the droppings of pigeons and examined a total of 18,900 non-destroyed diaspores to check for mucilage presence and germination ability. Out of all the examined diaspores, 4.5% were mucilaginous seeds. Among them, the highest number (12.2–13.5%) of viable diaspores belonged to the hemicellulosic type of mucilage (from Plantago species). Only 3.7% of germinating diaspores with pectic mucilage (Linum usitatissimum) were collected, and no seeds representing cellulosic mucilage (e.g., Ocimum basilicum). For non-mucilaginous plants, we collected only a few individual seeds (0.1% out of 8100 seeds used). We noted that the mucilaginous seeds found in the droppings were able to germinate; however, the germination ability was generally smaller in comparison to the control (i.e., not digested) seeds. Our results revealed that the presence of mucilage envelope has an impact on diaspore dispersal and survivability. With our experiments, we demonstrated for the first time that the mucilage envelope, especially of the non-cellulosic type, supports endozoochory. We also showed that non-mucilaginous seeds can be occasionally dispersed via endozoochory and are able to germinate. The results of our studies can explain the ways of plants distribution at a small, local scale as well as in long-distance dispersal, e.g., between islands or even continents.

The mucilage envelope of seeds has various functions including the provision of different ways for the dispersal of diaspores. Chemical composition and water content of the mucilage yield particular adhesive and frictional properties in the envelope that also influence the dispersal of seeds. To determine the physical properties ofPlantago lanceolataseed mucilage we studied (1) composition, (2) desiccation, (3) adhesion, and (4) friction properties of the mucilage under different hydration conditions. We revealed the presence of cellulose fibrils in the mucilage, which are responsible for a continuous and even distribution of the mucilaginous layer on the seed surface. The measured values of adhesive and frictional properties differed significantly in comparison to the previously studied pectic mucilage ofLinum usitatissimum. Also, the water loss from the cellulose mucilage was more rapid. The obtained different values can result from the presence of cellulose fibrils and their interaction with pectins in the mucilage. Because of this feature the mucilage ofP. lanceolatamay represent a more regularly ordered and stabile system than the pectic mucilage of flax, which lacks cellulose. In spite of the fact thatP. lanceolatamucilage revealed different adhesive and frictional properties than the pectic mucilage, it still demonstrates an effective system promoting zoochoric seed dispersal. Cellulose may additionally prevent the mucilage against loss from the seed surface.

Correlations between the morphology and cytology of invasive species and the effectiveness of invasion are among the most interesting questions in invasion ecology. Amongst exceptionally successful worldwide plant invaders, species of goldenrod (Solidago and Euthamia) are considered. The main aim of the study was to compare the morphology (concerning life traits) and cytology of the selected goldenrods occurring in south-western Poland with the effectiveness of their invasion. The results of the study, conducted in south-western Poland, showed that life traits of invasive Solidago and Euthamia taxa were clearly not connected with the effectiveness of invasion. The most widespread species, S. gigantea and S. altissima, had the highest ramets and uncommon species such as Euthamia graminifolia and S. virgaurea had short ramets. However, S. canadensis, which is tall, is also uncommon. The most frequent species (S. gigantea) produced smaller inflorescence than less frequent species (S. altissima, S. canadensis and Euthamia graminifolia). The spread of particular taxa was also not connected with the ploidy level and DNA content.

The seed mucilage envelope of myxospermatic diaspores is considered as a modified cell wall. Its chemical constitutes are mainly polysaccharide groups typical of the cell wall, however, pectins are very often the main component. A detailed analysis of the mucilaginous cell wall spatial architecture was demonstrated for the first time using a less-invasive CPD + SEM technique, which allowed the preservation of the mucilaginous cell wall structure. The examined pectic (Linum usitatissimum) and cellulose (Neopallasia pectinata) seed mucilage showed the fibrillary character of the components. The second type of mucilage indicated a much more arranged structure than that of the pectic one due to the presence of cellulose microfibrils. We showed cellulose organization in a net-like scaffold on which other mucilage components were spread and shoved how the mucilage was anchored to the seed surface through the cellulose skeleton, preventing it from being lost. Our detailed analysis gave an insight into how the mucilage is spatially arranged and also provided direct microstructural evidence of cell wall polysaccharides structure, distribution and interactions especially for widely-postulated xylan-cellulose linking. We demonstrated that xylan might be represented by long chains covering the surface of cellulose fibrils. The main advantage of the applied technique is its less-invasive character which retains the 3D structure of the components within the intact mucilaginous cell wall. As utilized in our studies, preparation and visualization methods with seed mucilage as a model system can give us new possibilities in structural studies of the (mucilaginous) cell wall.

Pilularia globulifera is a subatlantic European fern threatened with extinction. In Poland, it reaches the eastern border of its continuous range. Up to the end of the 20th century, it was observed here in 21 stands; only 2 of them existed by the second half of the century, so the species was categorized as critically endangered. Five new locations have been found in western and northwestern Poland during the last 10 years. Abundant and permanent populations grow in 3 locations, while 2 stands were ephemeral. All the current stands are situated in anthropogenic habitats with spontaneous vegetation, in oligotrophic to eutrophic waters. One of the new localities is about 280 km distant from the eastern range of the limit known previously. Pilularia forms its own plant community Pilularietum globuliferae, enters plots of Ranunculo-Juncetum bulbosi and occurs in mesotrophic to eutrophic rushes of Eleocharis palustris, Phragmites australis, Typha angustifolia and Equisetum fluviatile. Specimens are vigorous and regularly produce sporocarps.

Arnica, a genus including the medicinal species A. montana, in its Arbo variety, and A. chamissonis, is among the plants richest in essential oils used as pharmaceutical materials. Despite its extensive use, the role of anatomy and histochemistry in the internal secretory system producing the essential oil is poorly understood. Anatomical sections allowed differentiation between two forms of secretory structures which differ according to their distribution in plants. The first axial type is connected to the vascular system of all vegetative organs and forms canals lined with epithelial cells. The second cortical type is represented by elongated intercellular spaces filled with oil formed only between the cortex cells of roots and rhizomes at maturity, with canals lacking an epithelial layer.Only in A. montana rhizomes do secretory structures form huge characteristic reservoirs. Computed tomography illustrates their spatial distribution and fusiform shape. The axial type of root secretory canals is formed at the interface between the endodermis and cortex parenchyma, while, in the stem, they are located in direct contact with veinal parenchyma. The peripheral phloem parenchyma cells are arranged in strands around sieve tube elements which possess a unique ability to accumulate large amounts of oil bodies. The cells of phloem parenchyma give rise to the aforementioned secretory structures while the lipid components (triacylglycerols) stored there support the biosynthesis of essential oils by later becoming a medium in which these oils are dissolved. The results indicate the integrity of axial secretory structures forming a continuous system in vegetative plant organs.

The corticostriatal circuits are important information processing networks. There is evidence that these circuits may be dysfunctional in a variety of neuropsychiatric conditions ranging from Parkinson's disease to bipolar disorder. Cross-sectional fMRI studies may clarify normal circuit function, and longitudinal studies may provide information on changes related to age in control subjects, as well as illness progression and treatment response in patient groups. In this paper, we report a comprehensive analysis of the utility of several motor tasks as cross-sectional and longitudinal probes of corticostriatal function in terms of their activation strength and reliability. Our findings suggest that the motor tasks studied can be useful probes of corticostriatal function for studies utilizing group comparisons. However, longitudinal clinical studies in which individual results are important will need to take into account wide variation in individual activation and reliability. For example, measures of activation strength and reliability based on percent signal change display a dichotomy between simple motor tasks, which have high reliability and low activation, and complex tasks, which have lower reliability and higher activation. Size and overlap ratios calculated from activation maps produced a different view of reliability than intraclass correlation coefficients (ICC) based on percent signal change. Finally, these results suggest that the corticostriatal circuitry exhibit individualized responses to motor adaptation.

Chromosome counts in 16 populations of fiveArtemisia species from Poland are presented in this paper. Those ofA. annua (2n=18) andA. dracunculus (2n=90) are reported for the first time in Polish populations. The decaploid level (2n=90) is described for the first time in non-cultivated populations ofA. dracunculus, and several cases of aneusomaty (intraindividual aneuploid variations in chromosome number: 2n=87, 88 and 89) have been detected in this species. In addition to the already known diploid number (2n=18), the tetraploid level (2n=36) has been detected inA. absinthium. The same two numbers have been recorded inA. abrotanum, which represents the first tetraploid count in populations of this taxon occurring outside botanical gardens. Finally, the chromosome number ofArtemisia campestris subsp.sericea (tetraploid, 2n=36) is reported for the first time. The relevance of polyploidy for the evolution of the genus and other cytotaxonomic or cytobiogeographical aspects are briefly discussed.

Flax seeds produce mucilage after wetting. The mucilage due to its ability to absorb and maintain water is responsible for specific surface properties which are essential for seed dispersal in different ways. In the present paper, we asked how the hydration level affects the adhesive and frictional properties of the mucilage and which role does the mucilage play in seed dispersal? We have experimentally quantified: (1) desiccation dynamics of seeds with a mucilage envelope, (2) desiccation-time dependence of their friction coefficient, and (3) desiccation-time dependence of their pull-off forces on a smooth glass substrate. Freshly-hydrated seeds had an extremely low friction coefficient, which rapidly increased with an increasing desiccation time. Pull-off force just after hydration was rather low, then increased with an increasing water loss. Adhesion and friction experiments show that there is a clear maximum in the force values at certain hydration states of the mucilage. Different hydration levels of the mucilage can be employed in various dispersal mechanisms. Fully hydrated mucilage with its low viscosity gives optimal sliding conditions for endozoochory, whereas water loss provides conditions for the epizoochory. We suggest that the hydration level of the mucilage envelope can determine the potential mode of flax seed dispersal.

Eragrostisis a cosmopolitan genus of the familyPoaceae. Several wild species, includingE. pilosa(L.) Beauv., are harvested for food, but the only cultivated crop-species is tef [E. tef(Zucc.) Trotter]. Despite its importance as a staple food and its plasticity to diverse environmental conditions, little is known about the structural and physiological strategies that adapt tef seeds to endure diverse and variable moisture regimes. Here, we report the presence of slime cells, a type of modified epidermal cell, covering the fruit of tef and its wild relative,E. pilosa. The slime produced byEragrostisbelongs to the ‘true’ slime type, since it is exclusively composed of pectins. Pectin forms uniform layers on the cell wall inner surface, which are confined by a thin cellulose layer to prevent release into the cell lumen. In the presence of water, pectins quickly hydrate, causing swelling of the slime cells. This is followed by their detachment, which may be controlled by a thin cuticle layer on the fruit surface. The ability of slime to absorb and maintain moisture around the grain is thought to be an adaptive feature forEragrostisgrowing in dry habitats. This retention of water by slime may create conditions that are suitable for rapid germination.

11 páginas, 4 tablas., [EN] Genome size has been estimated by flow cytometry in 47 populations of 40 species of the tribe Anthemideae (Asteraceae), mainly from Artemisia and other genera of the subtribe Artemisiinae and related taxa. A range of 2C values from 3.54 to 21.22 pg was found. DNA amount per basic chromosome set ranged from 1.77 to 7.70 pg. First genome size estimates are provided for one subtribe, 10 genera, 32 species, and two subspecies. Nuclear DNA amount correlated well with some karyological, physiological and environmental characters, and has been demonstrated as a useful tool in the interpretation of evolutionary relationships within Artemisia and its close relatives., [FR]La taille du génome de 47 populations de 40 espèces de la tribu Anthemideae (Asteraceae), principalement du genre Artemisia et d’autres représentants de la sous-tribu Artemisiinae ou de groupes proches à celle-ci, a été estimée par cytométrie en flux. Les valeurs 2C sont comprises entre 3,54 et 21,22 pg. La quantité d’ADN par dotation chromosomique de base est comprise entre 1,77 et 7,70 pg. La taille du génome a été déterminée pour la première fois dans une sous-tribu, 10 genres, 32 espèces et deux sous-espèces. La quantité d’ADN nucléaire est en très bonne corrélation avec des caractères caryologiques, physiologiques et écologiques ; elle s’est avérée aussi utile pour l’interprétation des relations évolutives chez Artemisia et ses taxons apparentés., This work was supported by project BOS2001-3041-C02-01 of the Spanish government. Two of the authors (S.G. and M.S.) received predoctoral grants from the Spanish government and one of the authors (A.K.) received a grant from the Polish government (KBN 2396/W/IB/01).

The presented studies are focused on the comparative morphological and anatomical analyses of two wormwood varieties, i.e. the typical variety Artemisia absinthium var. absinthium and var. calcigena, endemic to the Pieniny Mountains (Western Carpathians). The studies comprise descriptions of the characteristics of pollen grains and the achene surface, analyses of seed germination rate and slime formation, stem anatomy, and leaf morphology and anatomy. The pollen grain surface is typical for the whole Artemisia genus. The seed coat consists of proper epidermal cells and slime cells, whose presence is related to the ability to form slime in both taxa. The obtained results show some typical xeromorphic features in the stem and leaf structure, which are more strongly pronounced in A. absinthium var. calcigena than in var. absinthium. These features include a continuous periderm layer and lignified pith cells developed in the early stages of growth. Although some differences between the studied taxa exist (e.g., better germination power, number of flower heads, length of pedicels and anatomy), they are rather a manifestation of phenotypic plasticity and habitat influence than the taxonomic identity. Based on the results we can state that A. absinthium var. calcigena presents a low position as an independent taxonomic unit and may exemplify a local phenotypic form.

This paper presents a karyological and cytogenetic characterisation of Artemisia absinthium var. absinthium and A. absinthium var. calcigena (Asteraceae, Anthemideae). Genome size (assessed as nuclear DNA amount), chromosome number, karyotype parameters, fluorochrome banding and fluorescent in situ hybridisation (FISH) of 18S–5.8S–26S and 5S rDNA were studied in Polish specimens of both varieties whose phylogenetic relationships were also established based on their molecular structure. The present study is the first with a focus on A. absinthium var. calcigena. The results basically agree with those previously reported from other A. absinthium populations and show no essential genome organization differences between the varieties., K. K. received a master student grant of the European Union’s LLP-Socrates programme to work at the University of Barcelona, J. P. a predoctoral grant from the Spanish Government (FPI program), S. G. a postdoctoral JAE Doc contract from the CSIC, and J. V. a grant from the Universitat de Barcelona in the frame of the Erasmus programme. This work was subsidized by DGICYT — Spanish Government (projects CGL2007-64839-C02-01 and CGL2007-64839-C02-02) and by the Uniwersytet Wrocławski (grant 2600/W/IBR/06).

The seed coat mucilage envelope is formed just after hydration and surrounds the seed as a gel-like, transparent capsule. The mucilage envelope represents a special type of modified cell wall with all of the typical polysaccharides i.e. cellulose, pectins and hemicelluloses. The chemical composition of the mucilage is well-recognized but its structural organization remains unclear. In the presented study, we visualized the spatial architecture of the seed mucilage envelope of selected taxa which produce cellulose mucilage. Using critical point drying (CPD) and scanning electron microscopy (SEM) imaging, we demonstrated the structural details of the mucilage from the micro- down to the nanoscale. The mucilage, after CPD, had a visibly spatial structure which differed between the studied taxa; for example, a tangled organization in Arabidopsis thaliana and a more ordered arrangement in Ocimum basilicum were revealed. In general, the mucilaginous fibrillary components formed network made of long, unbranched, thicker cellulose fibrils together with shorter, thinner and, often branched other polysaccharides. Cellulose fibrils built a kind of scaffold for the rest of the components which were spread between them and/or covered their surface. The cellulose fibrils were attached to the seed surface, and therefore prevent the loss of the mucilage envelope during mechanical impacts. The loose architecture and special chemical composition of the mucilaginous cell wall is important for water binding and storage, which are crucial for the proper functioning of the seed mucilage envelope.