Authors:M. F. Vianna, S. Pelizza, M. L. Russo, S. Rodriguez, and A. C. Scorsetti
The diversity of fungal endophytes is poorly known and particularly in the case of Nicotiana tabacum, the literature is limited. The present study assessed and compared the diversity and distribution of endophytic fungi between different organs of tobacco plants. We calculated the relative frequency and rates of colonisation and of isolation of endophytic fungi in roots, stems and leaves, as well as the Shannon–Wiener and Simpson diversity indexes. Similarities between assemblages from the studied organs were also analysed. A total of 1588 endophytic fungal strains assigned to 31 morphospecies were isolated. The highest diversity of endophytes was found in leaves, being Fusarium graminearum and Alternaria botrytis the most common fungal species. This study provides information on the distribution of fungal endophytes inhabiting leaves, stems, and roots of N. tabacum and thus can serve as a starting point for increasing our comprehension on the interactions in which these fungi are involved.
Authors:Eszter Laczkó-Zöld, Péter Forgó, István Zupkó, Eşianu Sigrid, and Judit Hohmann
Physalin D was isolated from the methanol extract of Physalis alkekengi L. fruits by combination of different chromatographic methods (CPC, TLC, HPLC). The structure was elucidated based on 1H and 13C NMR spectral analysis with the aid of 2D-correlation spectroscopy (1H, 1H-COSY, HSQC and HMBC) and comparison with literature data. The quantity of physalin D in mature and immature fruits and calyces was determined by RP-HPLC-UV method. Among the studied samples, immature calyx showed the highest content of physalin D (0.7880 ± 0.0612%), while mature calyx contained 4 times less amount (0.2028 ± 0.016%). The physalin D content of the fruit was much lower; immature fruits contained 0.0992 ± 0.0083% physalin D and mature fruits 0.0259 ± 0.0021%. The antiproliferative activity of the CHCl3 extract and its fractions was tested on three cancer cell lines (HeLa, MCF-7 and A431). The antiproliferative activity of physalin D is discussed with regard the published data.
Authors:R. Okada, H. Ikeno, T. Kimura, Mizue Ohashi, H. Aonuma, and E. Ito
A honeybee informs her nestmates of the location of a flower by doing a waggle dance. The waggle dance encodes both the direction of and distance to the flower from the hive. To reveal how the waggle dance benefits the colony, we created a Markov model of bee foraging behavior and performed simulation experiments by incorporating the biological parameters that we obtained from our own observations of real bees as well as from the literature. When two feeders were each placed 400 m away from the hive in different directions, a virtual colony in which honeybees danced and correctly transferred information (a normal, real bee colony) made significantly greater numbers of successful visits to the feeders compared to a colony with inaccurate information transfer. Howerer, when five feeders were each located 400 m from the hive, the inaccurate information transfer colony performed better than the normal colony. These results suggest that dancing’s ability to communicate accurate information depends on the number of feeders. Furthermore, because non-dancing colonies always made significantly fewer visits than those two colonies, we concluded that dancing behavior is beneficial for hives’ ability to visit food sources.
This paper describes aspects of the leaf anatomy of two Salvia taxa, Salvia nemorosa L. subsp. tesquicola (Klokov et Pobed.) Soó and Salvia nutans L., as well as their hybrid, Salvia ×dobrogensis Negrean, aiming to highlight common anatomical characteristics and superiority of the hybrid, compared with its parental taxa, less subject to these plants raised in the literature. Differences were found both in the structure of petiole and blade. For the petiole, differences arise concerning the degree of development of the external (collenchyma and chlorenchyma) and inner cortex. The vascular system in all considered taxa, comprises a great number of vascular bundles, with different levels of development of the conductive tissues. The mesophyll is heterogeneous, bifacial in S. nemorosa subsp. tesquicola and the hybrid, and equifacial in S. nutans. The presence and anatomy of numerous glandular and non-glandular trichomes (hairs), different in structure, shape and size, were investigated and evaluated. Stomata are present on both upper and lower epidermis of the blade having diacytic type, impressing, as well, an amphistomatic character. The vascular system of the midrib of the studied Salvia taxa is well developed, in particular those of the hybrid species. The analysis of petiole and blade anatomy of two Salvia taxa and their hybrid reveals common and specific features from which we could conclude that although the hybrid leaf is more developed anatomically than its parental taxa, the petiole has many features similar to that of Salvia nutans and the blade is almost similar to that of Salvia nemorosa species.
The northern lagoon of Tunis is closed, except for a limited communication with the sea via a very narrow channel. It is subjected, as the majority of Mediterranean lagoons, to environmental/anthropogenic constraints related mainly to the slowness of circulation and renewal of its waters, and also to surrounding human activities. Fifteen stations distributed in the northern lagoon of Tunis were sampled seasonally. The main physicochemical parameters of the water and the sediment were measured and the macro-invertebrates were sampled and identified. Results show that the nitrogen and phosphorus nutrients are relatively low in the study site compared with other Tunisian and Mediterranean lagoons, and the dissolved oxygen content and the pH are relatively satisfactory. However, the temperature and salinity which are higher compared with other Tunisian lagoons show remarkable seasonal variations, and seem to play interesting role in shaping community structure. Thus, the macrofauna community is poorly diversified and impoverished during warm/dry seasons, but slightly improved with precipitation and flow of freshwater during cool/rainy seasons. According to our own results and those of the literature, it seems that the northern lagoon of Tunis has for several years been affected by some major factors, mainly high temperature and salinity, sediment silting and perhaps an excess of organic matter. This has led to deep changes in the macrofauna community before being in its current status.
Authors:G. Kemény, K. Penksza, Nagy Z., and et al.
A neighbourding -quadrate transect study was conducted in order to examine the possibile relationship between small scale topography and coenotaxa occurrence and cover in subassociations of Festucetum vaginataeRapaics ex Soó 1929 sandy grassland plant community near Fülöpháza. These investigations served as a starting point in later soil seed bank studies. Cover of species was recorded in three transects of different exposition starting on the top of different dunes and ending in the depressions. Subassociations and facies forming species of the community occurred in all investigated transects. Parts of the transects could not have been classified unambiguously into any of the coenotaxa mentioned in the literature. In these zones the charactersitic species of the different subbasociations and facies were occurding together. These patches are propbably also the ones where changes in dominance relations and simultaneous spread of a species can relatively easily happen, as it is the case with Cleistogenes serotina. Annual vegetation of the open sandy grassland, ond the other hand, has occured only in the transition zones, between the subassociations or facies. In these transects moss-lichen synusia were peresent usually in the subassociation Festucetum vaginatae pennatae Kerner 1863.
In the present study, morphological and anatomical structures of cypsela – 12 Cirsium Miller (Carduoideae, Asteraceae) taxa belonging to two sections (sect. Cirsium and sect. Cephalonoplos) were investigated in detail with using stereomicroscope and light microscope. The taxa were evaluated comparatively in the aspect of carpological variations and their anatomies were presented in here for the first time. Morphological features including size, shape and colour of cypselae were examined. From anatomical observations, anatomical structures of pericarp, as well as the structure of testa were described. Cypselae colours differ from light brown to stramineous, sometimes with blackish striations. Their shapes change from oblong to oblanceolate, rarely obovate. The largest cypselae are present in C. echinus (1.59±0.03 mm × 4.68±0.07 mm) and the smallest ones are found in C. subinerme (1.20±0.02 mm × 2.97±0.05 mm). The pericarp is characterised by almost parenchymatous cells, while the testa is composed of lignified sclerenchymatous cell lines and crushed cells group. Secretory structure in testa bundle was evaluated. Results obtained from this study were compared with the present data in literature. Overall, morphological and anatomical characteristics of cypselae provide useful taxonomic markers in their classifications of the studied taxa of Cirsium but not distinctive for their sectional levels.
Environmental stress can lead to a reduction in developmental homeostasis, which could be reflected in increased variability of morphological traits. Fluctuating asymmetry (FA) is one possible manifestation of such a stress, and is often taken as a proxy for individual fitness. To test the usefulness of FA in morphological traits as an indicator of environmental quality, we studied the effect of urbanisation on FA in ground beetles (Carabidae) near a Danish city. First, we performed a critical examination whether morphological character traits suggested in the literature displayed true fluctuating asymmetry in three common predatory ground beetles, Carabus nemoralis, Nebria brevicollis and Pterostichus melanarius. Eight metrical (length of the second and third antennal segments, elytral length, length of the first tarsus segment, length of the first and second tibiae, length of the proximal and distal spines on the first femurs) and one meristic (the number of spines on the second tibiae) traits were examined. Most of them showed FA but not consistently. Females generally displayed a higher level of FA than males. Finally, we examined the changes in the level of FA in bilateral morphological traits along an urbanisation gradient (forest - suburban forest - forest fragments in urban park) to test whether environmental stress created by urbanisation is reflected in FA. Ground beetles common along a Danish urbanisation gradient did not seem to indicate differences in habitat quality by their level of FA.
An intense debate is underway on the different approaches to measuring the importance of neighbour interaction. Both the ecological meaning and the statistical suitability of one of the most popular indices have been seriously questioned, but no simpler and practical alternative tools have been proposed up to now. This paper proposes a novel approach based on the use of new normalized indices which scale the effects of neighbours and environment to the maximum target-plant potential. Two indices related to environmental suitability and size-asymmetry are suggested as tools to stratify data in homogeneous subsets before analysis, and an index of normalized neighbour effect (Nn) is proposed to integrate the measuring of neighbour importance and intensity. When tested on literature data, Nn index proves to be very highly correlated to the most currently used importance index. At the same time, it is moderately but significantly correlated to the intensity index. Yet, an accurate reanalysis of three published datasets proves that several detected trends are predictable on the basis of the inherent properties of the used indices. This is inextricably linked to the use of the same phytometers at different productivity levels. Thus, a glimpse is proposed towards the opportunity to use groups of equivalent competitors, each one working at a different point of the gradient, but all in a comparable range of environmental suitability and potential size-asymmetry relative to neighbours. Once defined these equivalence conditions, the normalized Nn metric is suited to measure how the relative weight of neighbour impact changes along the productivity gradient.