František Krahulec

Institute of Botany of the ASCR

Great progress in cytotaxonomic research during the last decades indicated an importance of relationships between morphological features, geographical distribution of plants, and chromosome counts. This study is aimed to fill the gaps in our knowledge on Bolboschoenus chromosome numbers related to morphological differentiation of plants and their d...

All plant populations fluctuate in time. Apart from the dynamics imposed by external forces such as climate, these fluctuations can be driven by endogenous processes taking place within the community. In this study, we aimed to identify potential role of soil‐borne microbial communities in driving endogenous fluctuations of plant populations. We co...

The occurrence of Papaver dubium L. under overhangs in the Veľká Fatra Mts., Slovakia, is evaluated with respect to its morphology, chromosome number and habitat conditions. We consider its occurrence under overhangs in high altitudes as a relic from the end of Last Glacial or early Holocene.

Floras and taxonomic papers covering the region of the Eastern Carpathians frequently include a taxon of the Valeriana tripteris and V. montana affinity, under various names, most frequently as Valeriana transsilvanica or V. tripteris subsp. heterophylla. After having collected and cultivated a new material from Slovakia and Poland, we discovered t...

Subalpine and alpine plant communities are considered highly sensitive and hence endangered by global changes. In central Europe, the highly sensitive habitats are also influenced by human activities: land use, industrial pollution, and tourism. That is especially true for subalpine plant communities formed on mid-latitude mountains during specific...

Ecological theory posits that temporal stability patterns in plant populations are associated with differences in species' ecological strategies. However, empirical evidence is lacking about which traits, or trade-offs, underlie species stability, especially across different biomes. We compiled a worldwide collection of long-term permanent vegetati...

Root densities in the field vary at the centimetre scale, but we have no information on whether this variation is linked to the variation in nutrient concentrations and availability. Roots of many species are able to proliferate in nutrient‐rich patches in controlled conditions in culture, but because data on nutrient concentrations and, in particu...

Lycopsis orientalis has been known from the Czech Republic as individual plants found three times. We report here on its occurrence in five new localities, from the north-western, central and eastern part of the country. This fact suggests that it is locally fully naturalised and its further spread is highly probable. We found chromosome numbers 2n...

Ecological theory posits that temporal stability patterns in plant populations are associated with differences in species’ ecological strategies. However, empirical evidence is lacking about which traits, or trade-offs, underlie species stability, specially across different ecosystems. To address this, we compiled a global collection of long-term p...

Aims Dynamics of plant communities are an outcome of species’ responses to the external environment influenced by species’ life history, growth patterns and their mutual interactions. We aimed to disentangle the long‐term directional trends, likely associated with decadal change in environmental conditions, from short‐term species fluctuations. Lo...

The efficient uptake of nutrients depends on the ability of roots to respond to gradients of these resources. Although pot experiments have shown that species differ in their ability to proliferate their roots in nutrient‐rich patches, the role of such differences in determining root shapes in the field is unclear. We used fine‐scale quantitative (...

This paper summarises the principal factors underlying the variation of Pilosella populations in the fi eld: 1. Variation of taxa (basic, and hybridogenous species, recent hybrids); 2. Variation in chromosome number; 3. Variation in breeding systems; 4. Hybridization; 5. Population structure. Suggestions on how to study Pilosella populations are gi...

Paper gives preliminary classification of plant communities of the dry part od Great Alvar, an island in Baltic Sea (Sweden).

Introduction and objectives: The members of the genus Pilosella are native in Europe and Asia, but they are successful invasive species on most continents. These species form an agamic complex with common apomixis. Apomictic species hybridize, they have different degree of residual sexuality. Main aim of this paper was to determine if the interspec...

Osevní směsi jako potenciální zdroj ohrožených a nepůvodních druhů Zvýšený zájem veřejnosti o osevní směsi prezentované pod zastřešujícím názvem "Květnatá louka" či "Květnice" v posledních letech přilákal celou řadu fi rem, které rozšířily dosavadní portfolio osevních smě-sí na trhu. Firmy buď produkují své vlastní osivo, nebo ho nakupují a směsi m...

Studies on plant viruses are concentrated mainly towards crop diseases and little is known about viruses in wild and ornamental species. We surveyed viruses infecting 65 vegetable, wild and ornamental Allium species cultivated or naturally occurring in the Czech Republic. Allium plants were collected from six habitat categories (botanical gardens;...

Urfus T., Vít P., Urfusová R. & Krahulec F. (2020) Morphology mirrors ploidy and reproductive modes in Pilosella officinarum.-Preslia 92: 391-402. Pilosella officinarum is represented predominantly by tetraploid (2n = 36), pentaploid (2n = 45) and hexaploid (2n = 54) cytotypes reproducing, to various degrees, both sexually and apomictically. Its cu...

This paper summarises data on altogether 25 localities of Cardamine occulta, an Eastern Asian alien, recognized for the first time in the Czech Republic in 2016. After a targeted search in herbaria, the date of the first occurrence of this species on the Czech territory had to be shifted to 2006. However, the first finds come from garden shops wher...

Spontaneous hybrids of two Doronicum species, D. hungaricum and D. orientale, were found in a garden after the first year of their common cultivation. This hybrid has already been found in South Hungary and has been described as D. ×sopianae. The morphological characters of the hybrid with their parents were compared. Because both parental species...

2020): Ploidy level and breeding system in some populations of Pilosella (Asteraceae) in eastern and southern Slovakia.-Thaiszia-J. Bot. 30 (1): 037-058. Abstract: The ploidy level/breeding system was determined in following species and hybrids originating from populations of the agamic polyploid complex of Pilosella in Slovakia: P. bauhini (either...

Roots are capable of strong plastic responses to environmental signals, but the extent of such responses in the field is essentially unknown. Here, we aimed to identify interspecific root aggregations and segregations as indicators of plastic responses to the presence of other species. Furthermore, we asked whether aggregations change with heteroge...

Aim The outcome of interaction between plant individuals is often expected to be determined by differences in their sizes with other traits playing minor roles. However, such findings typically come from manipulative experiments in experimental gardens. Consequently, little is known about the relative roles of size vs. other traits in the field, pa...

Invasive plant species reduce biodiversity, alter ecosystem processes, and cause economic losses. Control of invasive plants is therefore highly desired by land managers and policy makers. However, invasive plant control strategies frequently fail, partly because management often concentrates only on the eradication of invasive plants and not on re...

Hybridization, polyploidization and crop‐to‐wild gene transfer within the agriculturally important tribe Triticeae are well explored experimentally, but the true consequences of both phenomena under natural conditions remain understudied. The present paper reports on an investigation of three species of couch grasses (Elymus hispidus, E. repens and...

Populations of Pilosella species in ruderal habitats in the city of Prague: consequences of the spread of P. aurantiaca and P. rothiana Populace druhů rodu Pilosella na ruderálních stanovištích v Praze: následky expanze P. aurantiaca a P. rothiana Populations of Pilosella species in ruderal habitats in the city of Prague: consequences of the spread...

Residual sexuality of the apomict Pilosella rubra under natural conditions in the Krkonoše Mts.-Preslia 92: 403-428. Because of residual sexuality, a maternal facultatively apomictic plant is able to produce more than just apomictic progeny. The production of such non-apomictic progeny has been studied in open-pollinated Pilosella rubra, a hexaploi...

Invasive plant species reduce biodiversity, alter ecosystem processes and cause economic losses. Control of invasive plants is therefore in high demand by land managers and policymakers. However, invasive plant control frequently fails, partly because management often concentrates only on the eradication of the invasive plants, but not on revegetat...

We studied degree of residual sexuality at Pilosella rubra, an endemic of the Krkonoše Mts., by two different methods: 1. Experimental hybridization of hexaploid P. rubra (mother plant) and tetraploid P. officinarum (pollen donator) followed by analysis of ploidy of progeny (Krahulcová et al. 2004). 2. Collection of achenes from P. rubra in the fi...

Key to the all native, non-native and frequently cultivated Allium species occuring at the area of the Czech Republic.

There is remarkable variation in life histories of coexisting plant species. These “alternative designs” for the given set of environmental conditions are likely to play a role in species niche differences and thus may underlie species coexistence, although there is no clear demonstration of it. Currently available data on within‐community differen...

While plant roots respond consistently to nutrient availability under experimental conditions, our understanding of the role of such response in the field is hindered by poor knowledge of size and duration of nutrient patches there. In particular, knowledge of patch duration is critically important for understanding types of root response. We deter...

The species-mixed Pilosella populations comprising diploid sexual and polyploid facultatively apomictic biotypes were studied in Bulgaria. Parentage of co-occurring recent hybrids was inferred from a combination of morphology and ploidy level that corresponded to simple/multiple crosses of basic species via either reduced or unreduced gametes. The...

Gametophytic apomixis (asexual seed formation without syngamy of female and male gametes) is a highly interesting mechanism for researchers in plant biotechnology, genetics, evolutionary biology, and taxonomy. Apomixis evolved repeatedly and independently in the evolution of multiple genera. It is an effective reproduction barrier and, consequently...

Vertical differentiation in root placement is one of the potential mechanisms of plant niche differentiation. It can be due to the remarkable plasticity of roots in response to nutrients and neighbours, but most data on it come from pot or garden experiments. The roles of vertical differentiation and of plasticity in it in the field are thus not we...

Several dynamic models have shown that dynamics of legumes and grasses can result in periodic behaviour. These oscillations arise due to delays in nitrogen flows coupled with differences in ability to compete for light. However, long‐term time series on legume dynamics that could be used to test predictions of these models are almost non‐existent....

Background and aims: Aesculus L. (horse chestnut, buckeye) is a genus of 12-19 extant woody species native to the temperate Northern Hemisphere. This genus is known for unusually large seeds among angiosperms. While chromosome counts are available for many Aesculus species, only one has had its genome size measured. The aim of this study is to pro...

This paper presents an analysis of the disjunctive distribution patterns of vascular plants in the central part of the Sudetes, a mountain range in central Europe. These disjunctions concern mainly species occurring in the highest massifs located over 100 km apart. We studied (1) distribution patterns of 55 taxa in the Sudetes defined on the basis...

Chromosome numbers and breeding systems are given for a set of Pilosella species occurring in Bulgaria and SW Romania (Banat). All diploids and tetraploid accessions of P. bauhini and P. cymosa subsp. sabina were found sexual, and tetraploid P. pavichii both sexual and apomictic. One hexaploid accession of P. bauhini was found sexual, but semisteri...

We studied the significance of sexual reproduction as a source of ploidy level variation in a model system consisting of hexaploid, facultatively apomictic Pilosella bauhini and tetraploid, sexual P. officinarum. As the maternal parent, apomictic P. bauhini generated higher ploidy level variation than sexual P. officinarum. Ploidy levels of its pro...

We studied a small, spatially limited population of Pilosella plants, rich inmorphological types, in the southwestern part of central Bohemia, Czech Republic. The following tetraploid parental Pilosella species putatively gave rise to the hybrid swarm analysed: sexual P. officinarum and apomictic P. polymastix (P. bauhini-P. caespitosa). In additio...

The effect of maternal, facultatively apomictic plants on population diversity was evaluated in seven hybridizing polyploid Pilosella populations, where apomictic (P. bauhini or P. aurantiaca) and sexual (P. officinarum) biotypes coexist. The ploidy level, reproductive system, morphology, clonal structure and chloroplast DNA haplotypes were used to...

We traced hybridization processes taking place within a mixed population of Pilosella piloselloides subsp. bauhini and P. officinarum by means of a morphometric analysis of plants sampled in the field. Our results show that hybridization is frequent between the two taxa as well as between their two stabilized hybrids (P. brachiata and P. leptophyto...

Chromosome counts/DNA ploidy level (DNA-PL) and modes of reproduction of the following species, hybridogenous species and hybrids of Pilosella from the Krkonoše Mts (Czech Republic) are reported: P. aurantiaca (2n = 36,2n = 45, DNA-PL tetraploid, pentaploid, all apomictic); P. bauhini subsp. bauhini (2n = 45, with a long hemizygous marker chromosom...

Tragopogon ×mirabilis Rouy is described as a diploid hybrid between T. porrifolius and T. pratensis. A population of T. ×mirabilis from Central Bohemia, Czech Republic, was recently investigated and, unlike previous reports of T. ×mirabilis, was found to be highly fertile. This fertile diploid hybrid population was considered to represent an altern...

Many plant communities show strong fine‐scale spatiotemporal dynamics due to frequent natality and mortality events. This process is often non‐random, implying that the community can be broken into groups within which species mutually replace each other in time and are distinct from the other such groups. We examined whether such groups fill separa...

A brief history of the botanical research on the flora and vegetation in the Czech Republic is presented. This is done in the context of the progress in botany in neighbouring countries as well as the development of the society, especially the establishment of scientific institutions in the different countries. Important botanists who worked in oth...

A complete list of all alien taxa ever recorded in the flora of the Czech Republic is presented as an update of the original checklist published in 2002. New data accumulated in the last decade are incorporated and the listing and status of some taxa are reassessed based on improved knowledge. Alien flora of the Czech Republic consists of 1454 taxa...

Neither the genetic basis nor the inheritance of apomixis is fully understood in plants. The present study is focused on the inheritance of parthenogenesis, one of the basic elements of apomixis, in Pilosella (Asteraceae). A complex pattern of inheritance was recorded in the segregating F(1) progeny recovered from reciprocal crosses between the fac...

The present paper reviews mechanisms producing complicated patterns of variation withinHieracium subgen.Pilosella. The taxonomic complexity of this subgenus is due to highly variable basic species and intermediate (hybridogenous) species. The most important sources of variation are polyploidy, hybridization and (mostly) facultative apomixis of the...

Pilosella aurantiaca – tetraploid, fakultativ apomiktisch und eingebürgert – und P. officinarum – tetraploid, sexuell und einheimisch – bilden bei Hagen, Nordrhein-Westfalen, einen Hybridschwarm aus tetra- und hexaploiden Pflanzen. Der Hybridschwarm wurde 1990 auf einer inzwischen brach gefallenen Wiese gefunden. Seit 20 Jahren kommt hier fast unve...

The distribution and habitat conditions of two taxa of the genus Allium sect. Allium (Allium sphaerocephalon, Allium vineale) were studied on the territory of the Czech Republic. Allium sphaerocephalon is a rare species which inhabits two types of habitat: thermophilous, perennial vegetation of rock outcrops (Alysso-Festucion pallentis alliance) an...

Within a population of invasive Hieracium pilosella in Chilean Patagonia we found two ploidy levels, pentaploid and hexaploid. Each ploidy level was represented by one clone. Their reproductive system was apomictic (and thus replicating the maternal genome), with a low degree of residual sexuality. It is neces-sary to prevent the evolution of new b...

The spatial distribution of cytotypes can provide valuable insights into the evolution of polyploid complexes. Previously, only tetraploid Allium oleraceum was reported from Slovakia. Analysing 863 individuals from 93 populations from Slovakia revealed an extensive variation in theDNAploidy levels of Allium oleraceum (3x, 4x, 5x and 6x). Of the mai...

Haploid parthenogenesis in facultatively apomictic Pilosella generated polyhaploid progeny (with half the maternal chromosome set) both in natural populations and garden experiments. Production of polyhaploids varied considerably among different species, hybridogenous species and hybrids. In the field (14 localities), the highest frequency of polyh...

Populations of Pilosella (Hieracium subgenus Pilosella) at ruderal localities were investigated in an urban area (Prague City) with respect to their distribution, variation in DNA ploidy level/chromosome number and mode of reproduction. The following species, hybridogenous species or hybrids (with ploidy level/chromosome number and mode of reproduc...

Reproductive variation was studied in the tetraploid Pilosella aurantiaca, hexaploid P. rubra (both species with facultative autonomous apospory) and in their 2n + n hybrids, which were obtained by crossing with a sexual pollen parent (tetraploid P. officinarum). The different DNA content in P. aurantiaca and P. officinarum demonstrated the actual...

Despite extensive study of polyploidy, its origin, and ecogeographical differences between polyploids and their diploid progenitors, few studies have addressed ploidy-level structure and patterns of ecogeographical differentiation at various spatial scales using detailed sampling procedures. The pattern of coexistence of polyploids in the geophyte...

Mowing and management to reduce nutrient levels have often been successfully used to restore species‐rich grasslands in various parts of Europe. However, such treatments have failed to restore the species‐rich Central European mountain grasslands dominated by Polygonum bistorta . P. bistorta builds an extensive underground rhizome system that monop...

This is the chapter from the book "Flora of the Czech Republic" dealing with the taxa of the genus Allium occurring on the territory of the Czech Republic.

The capacity to generate variation in ploidy and reproductive mode was compared in facultatively apomictic versus sexual maternal plants that coexist in two model populations. The population structure was studied in polyploid hybrid swarms comprised of Hieracium pilosella (usually sexual, less commonly apomictic), H. bauhini (apomictic), and their...

Sheep grazing was investigated as an alternative to traditional management of meadows in the Krkonoše Mts. Until the second World War these meadows were mown in mid-summer and grazed by cattle for the rest of the season. Subsequent abandonment of the meadows has resulted in decreasing species richness. Degradation phases of the former communities h...

The distribution and habitat conditions of two taxa of the genus Allium sect. Allium (Allium scorodoprasum, A. rotundum) were studied on the territory of the Czech Republic. Allium scorodoprasum is sparsely distributed in two large but isolated areas (East Bohemia, northern part of Central Bohemia, and North andWest Bohemia; South, Central and East...

We studied the agamic complex of Hieracium subgen. Pilosella in the Šumava/Böhmerwald, the borderland between the Czech Republic and Germany. Their DNA ploidy levels/chromosome numbers, breeding systems, chloroplast haplotypes as well as the clonal structure of apomicts were determined. The complex consists of the following basic and intermediate s...

Pilosella officinarum (syn. Hieracium pilosella) is a highly structured species with respect to the ploidy level, with obvious cytogeographic trends. Previous non-collated data indicated a possible differentiation in the frequency of particular ploidy levels in the Czech Republic and Slovakia. Therefore, detailed sampling and ploidy level analyses...

Hieracium sub-genus Pilosella (hawkweeds) is a taxonomically complicated group of vascular plants, the structure of which is substantially influenced by frequent interspecific hybridization and polyploidization. Two kinds of species, 'basic' and 'intermediate' (i.e. hybridogenous), are usually recognized. In this study, genome size variation was in...

Natural hybridization was investigated between two predominantly allohexaploid wheatgrasses, weedy Elytrigia repens and steppic E. intermedia, with respect to habitats characterized by different degrees of anthropogenic disturbance. Using flow cytometry (relative DNA content), 269 plants from three localities were analysed. Hybrids were further ana...