For many years, research has been carried out to understand the mechanism of auxin action, its biosynthesis, catabolism, perception, and transport. One central interest is understanding the ...auxin-dependent gene expression regulation mechanism involving AUXIN RESPONSE FACTOR (ARF) transcription factors and their repressors, the AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) proteins. Numerous studies have been focused on the MONOPTEROS (MP)/ARF5, an activator of auxin-dependent gene expression with a crucial impact on plant development. This review paper summarizes over thirty years of research on MP/ARF5. We indicate the available analytical tools to study MP/ARF5 and point out the known mechanism of MP/ARF5-dependent regulation of gene expression during various developmental processes, i.e., embryogenesis, leaf formation, vascularization, and shoot and root meristem formation. However, many questions remain about the auxin-dose-dependent regulation of gene transcription by MP/ARF5 and its isoforms in plant cells, the composition of the MP/ARF5 protein complex, and finally, the list of genes under its direct control. In addition, the information on post-translational modifications of MP/ARF5 protein is marginal, and knowledge about their consequences on MP/ARF5 function is limited. Moreover, the epigenetic factors and other regulators that act upstream of MP/ARF5 are poorly understood. Their identification will be a challenge in the coming years.
The fragmentation and isolation of preserved habitat patches within intensive agricultural landscape threaten species survival in steppes. In Ukraine, <5 % of the original steppe area has survived, ...mostly in nature reserves, loess ravines and kurgans (burial mounds). The latter are small, but relatively numerous objects. The aim of this study was to investigate whether plant species density (= the number of species per plot) within small steppe patches on kurgans differs from that within large steppe enclaves in southern Ukraine. Another aim was to determine the influence of patch area, isolation and heat load index on species density on kurgans. Presence-absence data for vascular plant species were collected on plots of a size of 100 and 1 m
2
. Thirty kurgans and ten sites within large steppe enclaves were sampled. Every noted species was classified as specialist or generalist. For kurgans data on area and degree of isolation were collected. Additionally the heat load index for plots on kurgans was calculated. The density of habitat specialists was higher in larger steppe enclaves than on kurgans at both spatial scales. On kurgans the most important predictors of specialist density were isolation (negative) and kurgan area (positive). The density of generalists was positively affected by the heat load index. Kurgans can provide refuges for steppe plant species. However, our results show that over a longer time period, proximity to larger steppe refuges is important to maintain species diversity within these small patches.
Heavy metal (As, Mn, Ni, Sn, Ti) concentrations were determined in soil and plant samples collected in different areas of the railway junction Iława Główna, Poland. Soil and plant samples were ...collected in four functional parts of the junction, i.e. the loading ramp, main track within the platform area, rolling stock cleaning bay and the railway siding. Four plant species occurring in relatively higher abundance were selected for heavy metals analysis, although in the loading ramp and platform areas only one species could be collected in the amount which makes chemical analysis possible. The selected species included three perennials (Daucus carota, Pastinaca sativa and Taraxacum officinale) and one annual plant (Sonchus oleraceus).
The entire area of the railway junction showed elevated concentrations of heavy metals when compared to the control level. It was most pronounced for the platform area and railway siding. The concentration of arsenic, manganese and nickel in plants growing in these parts of the junction exceeded the toxic level. The highest contamination of soil and plants found in the platform area suggested advanced emission process of the analyzed metals from wheel and track abrasion. Literature review showed that the concentration of the investigated metals in soil was generally higher than that found in centers of cities and along traffic roads proving that the railway is an important linear source of soil contamination
W pracy przedstawiono wyniki badań dotyczące zawartości wybranych metali ciężkich (As, Mn, Ni, Sn, Ti) w glebie i roślinach na obszarze węzła kolejowego Iława Główna. Próby gleby i roślin pobierano w czterech częściach węzła, a mianowicie na rampie załadowczej, torowisku głównym, myjni i bocznicy kolejowej. Na całym obszarze węzła kolejowego stwierdzono podwyższone stężenia metali ciężkich w porównaniu z terenem kontrolnym. Najwyższe stężenia stwierdzano na torowisku głównym i bocznicy kolejowej. Stężenie arsenu, manganu i niklu w roślinach występujących na tym obszarze przekracza poziom toksyczny. Najwyższe zanieczyszczenie gleby i roślin stwierdzane na torowisku wskazuje na występowanie procesów emisji metali spowodowanych ścieraniem kół i szyn. Porównanie z danymi literaturowymi wskazuje, że stężenie badanych metali w glebie jest większe niż w glebach centów miast i wzdłuż drogowych szlaków komunikacyjnych, co dowodzi, że linie kolejowe stanowią istotne liniowe źródło zanieczyszczenia gleby
The aim of the work was to estimate the specific role that Central European botanic gardens play in the dispersal of alien plants, which results from the wide variety of plants cultivated in the ...gardens and regular international exchange of plant material between these institutions. We compared the results of recent field studies (in eight Polish botanic gardens) and a review of older literature data and herbarium collections (from Central European botanic gardens). We found that in Poland the proportion of botanic garden escapes was lower (3%) than would be expected from the "tens rule". Botanic gardens have played a considerable role in the development of the synanthropic flora of Central Europe in the last 200 years. We determined a group of species introduced through a network of botanic gardens and propose 5 theoretical patterns to describe the mode and pathways of the early stages of introduction of these species.
Flora parku Pole Mokotowskie w Warszawie Sudnik-Wójcikowswska, Barbara; Jędrzejewska-Szmek, Krystyna; Sikorski, Piotr
Prace i studia geograficzne,
2020, Letnik:
65, Številka:
1
Journal Article
Odprti dostop
The history of the Pole Mokotowskie – city park in Warsaw, has strongly influenced its flora. Its fertile habitats of oak-lime-hornbeam forests, two hundred years ago were occupied by farmlands, ...later converted into Russian military areas, a horse racing track, and even an airport. As a result, today’s Pole Mokotowskie has a rich flora (over 350 species) and is covered by forests planted no more than 70 years ago (native and alien tree species, most occurring due to natural regeneration). Forest undergrowth has slightly recovered. Nearly half of the flora are species typical for meadows, grasslands and lawns. The most interesting and richest in plant species area is the moderately moist meadow located in the southern part of the park, usually mown once a year. Also introduction of so-called “flower meadow” was perform in part of the area but appeared to be little successful experiment, which only temporarily enriched the flora of the park in colourfully blooming annual species. The share of alien species, mainly ruderals, occupying the margins, roadsides, abandoned sports facilities and the immediate vicinity of buildings, is slightly lower in the park’s flora than in the flora of Warsaw.
Floristic studies were carried out in NE Poland in 2007-2008 in three types of railway areas: operating tracks, tracks abandoned less than 10 years ago, and tracks abandoned more than 10 years ago. ...In the 41 sections of railway tracks surveyed, 338 species were recorded, including 22 species that occurred at > 50% frequency, 27 species strongly associated with operating railway areas, and 4 species typical of railway areas in Poland. Comparative analysis of the flora of the 3 types of railway areas investigated showed significant differences in the richness and structure of their floras.
In 2007-2008, floristic studies were carried out in active railway areas in NE Poland, as well as on railway tracks, which had been abandoned at different times. Only homogeneous habitats were ...surveyed (the area between the tracks and a narrow transect running parallel to the tracks). Trends in the transformation of the flora in abandoned railway areas were discussed: the retreat of alien species with a short life cycle, the encroachment of native perennial plants and an increase in the number of trees.
To understand the molecular mechanism controlling in vitro plant morphogenesis, a culture system enabling induction of alternative morphogenic pathways (somatic embryogenesis, SE; shoot ...organogenesis, ORG) in a well defined population of somatic cells is needed. Arabidopsis is the most useful model plant for genomic studies, but a system in which SE or ORG can be induced alternatively in the same type of explant has not been proposed. Immature zygotic embryos (IZEs) of Arabidopsis provide the only explants with embryogenic potential, and have been recommended for studying mechanisms of SE induced in vitro. This study was aimed at defining culture conditions promoting induction of alternative morphogenic pathways: shoot ORG in IZE explants. The established protocol involves pretreatment of IZE explants with liquid auxin-rich callus induction (CIM) medium, followed by subculture on solid cytokinin-rich shoot induction medium (SIM). The method enables efficient shoot induction in Columbia (Col-0) and Wassilewskija (Ws), genotypes commonly used in molecular studies. During 3 weeks of culture up to 90% of Col-0 and 70% of Ws explants regenerated shoots via an indirect morphogenic pathway. We analyzed the qRT-PCR expression patterns of the LEC (LEC1, LEC2 and FUS3) genes, the key regulators of Arabidopsis embryogenesis, in the IZE explants induced to promote shoot ORG. The sharp decline of LEC expression on SIM medium confirmed that culture of Arabidopsis IZE explants enables experimental manipulation of the morphogenic response of somatic cells. A scheme illustrating various in vitro morphogenic responses of IZEs in relation to hormonal treatment is presented.
Results of the studies on the floristic biodiversity of the kurgans in the Pontic desert steppe of the Black Sea Lowland (Kherson Region) are presented. Twenty-six of about 130 kurgans higher than 3 ...m, distributed over an area of approx. 1500 km2, were surveyed and the flora of 5 microhabitats within every kurgan (top, southern and northern slope, southern and northern foot) was examined. The richness of the kurgan flora is estimated at 305 species. Species of alien origin constituted 23% of the total flora, which indicates limited anthropogenic influence. Species of two classes, Festuco-Brometea and Stellarietea mediae were predominant, which also confirmed the semi-natural character of the kurgan flora. The lowest number of species was recorded on top, which was relatively rich in synanthropes, particularly therophytes (Stellarietea mediae). The north side was richer in species than the south side of the kurgans. Steppe species were the most stable and important component of the flora of the slopes (45-47% of the species represented the class Festuco-Brometea). The total flora of the foot contained more species and was more diversified than the flora of the slopes (although the mean number of species was similar in both habitats), but each species occurred at low frequency. There was a higher proportion of species which were introduced from the area surrounding the kurgans, e.g. weeds, halophytes, meadow species, as well as trees which are rarely found in the desert steppe zone. In spite of the small size of the kurgans, significant differences between the floristic composition of the various microhabitats were detected.
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