Parenchyma represents a critically important living tissue in the sapwood of the secondary xylem of woody angiosperms. Considering various interactions between parenchyma and water transporting vessels, we hypothesize a structure-function relationship between both cell types. Through a generalized additive mixed model approach based on 2,332 woody angiosperm species derived from the literature, we explored the relationship between the proportion and spatial distribution of ray and axial parenchyma and vessel size, while controlling for maximum plant height and a range of climatic factors. When factoring in maximum plant height, we found that with increasing mean annual temperatures, mean vessel diameter showed a positive correlation with axial parenchyma proportion and arrangement, but not for ray parenchyma. Species with a high axial parenchyma tissue fraction tend to have wide vessels, with most of the parenchyma packed around vessels, whereas species with small diameter vessels show a reduced amount of axial parenchyma that is not directly connected to vessels. This finding provides evidence for independent functions of axial parenchyma and ray parenchyma in large vesselled species and further supports a strong role for axial parenchyma in long-distance xylem water transport.

• Klíčová slova
• angiosperms, climate, maximum plant height, parenchyma, precipitation, temperature, vessel diameter, water transport, wood anatomy, xylem,
• MeSH
• déšť MeSH
• dřevo anatomie a histologie   MeSH
• Magnoliopsida anatomie a histologie   MeSH
• podnebí MeSH
• teoretické modely MeSH
• teplota MeSH
• xylém anatomie a histologie   MeSH
• Publikační typ
• časopisecké články MeSH

Overview of pollen development. Male gametophyte development of angiosperms is a complex process that requires coordinated activity of different cell types and tissues of both gametophytic and sporophytic origin and the appropriate specific gene expression. Pollen ontogeny is also an excellent model for the dissection of cellular networks that control cell growth, polarity, cellular differentiation and cell signaling. This article describes two sequential phases of angiosperm pollen ontogenesis-developmental phase leading to the formation of mature pollen grains, and a functional or progamic phase, beginning with the impact of the grains on the stigma surface and ending at double fertilization. Here we present an overview of important cellular processes in pollen development and explosive pollen tube growth stressing the importance of reserves accumulation and mobilization and also the mutual activation of pollen tube and pistil tissues, pollen tube guidance and the communication between male and female gametophytes. We further describe the recent advances in regulatory mechanisms involved such as posttranscriptional regulation (including mass transcript storage) and posttranslational modifications to modulate protein function, intracellular metabolic signaling, ionic gradients such as Ca(2+) and H(+) ions, cell wall synthesis, protein secretion and intercellular signaling within the reproductive tissues.

• Klíčová slova
• Flowering plants, Male gametophyte, Pollen development, Pollen tube growth,
• MeSH
• Magnoliopsida růst a vývoj   metabolismus   MeSH
• pyl růst a vývoj   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

Nuclear DNA contents for 104 Macaronesian angiosperms, with particular attention on Canary Islands endemics, were analysed using propidium iodide flow cytometry. Prime estimates for more than one-sixth of the whole Canarian endemic flora (including representatives of 11 endemic genera) were obtained. The resulting 1C DNA values ranged from 0.19 to 7.21 pg for Descurainia bourgeauana and Argyranthemum frutescens, respectively (about 38-fold difference). The majority of species, however, possessed (very) small genomes, with C-values <1.6 pg. The tendency towards small nuclear DNA contents and genome sizes was confirmed by comparing average values for Macaronesian and non-Macaronesian representatives of individual families, genera and major phylogenetic lineages. Our data support the hypothesis that the insular selection pressures in Macaronesia favour small C-values and genome sizes. Both positive and negative correlations between infrageneric nuclear DNA amount variation and environmental conditions on Tenerife were also found in several genera.

• MeSH
• buněčné jádro genetika   MeSH
• chromozomy rostlin MeSH
• DNA rostlinná analýza   MeSH
• fylogeneze MeSH
• genom rostlinný MeSH
• Magnoliopsida klasifikace   genetika   MeSH
• molekulární evoluce MeSH
• zeměpis MeSH
• životní prostředí MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• ostrovy Atlantského oceánu MeSH
• Názvy látek
• DNA rostlinná MeSH

Angiosperms with large genomes experience nuclear-, cellular-, and organism-level constraints that may limit their phenotypic plasticity and ecological niche, which could increase their risk of extinction. Therefore, we test the hypotheses that large-genomed species are more likely to be threatened with extinction than those with small genomes, and that the effect of genome size varies across three selected covariates: life form, endemism, and climatic zone. We collated genome size and extinction risk information for a representative sample of angiosperms comprising 3250 species, which we analyzed alongside life form, endemism, and climatic zone variables using a phylogenetic framework. Genome size is positively correlated with extinction risk, a pattern driven by a signal in herbaceous but not woody species, regardless of climate and endemism. The influence of genome size is stronger in endemic herbaceous species, but is relatively homogenous across different climates. Beyond its indirect link via endemism and climate, genome size is associated with extinction risk directly and significantly. Genome size may serve as a proxy for difficult-to-measure parameters associated with resilience and vulnerability in herbaceous angiosperms. Therefore, it merits further exploration as a useful biological attribute for understanding intrinsic extinction risk and augmenting plant conservation efforts.

• Klíčová slova
• C‐value, IUCN Red List, conservation status, endemic species, life form, nucleotype, plant traits,
• MeSH
• délka genomu * MeSH
• extinkce biologická * MeSH
• fylogeneze * MeSH
• genom rostlinný MeSH
• Magnoliopsida * genetika   fyziologie   MeSH
• podnebí MeSH
• Publikační typ
• časopisecké články MeSH

Spatio-temporal assessment of phylogenetic diversity gradients during the Holocene (past 12,000 years) provides an opportunity for a deeper understanding of the dynamics of species co-occurrence patterns under environmental fluctuations. Using two robust metrics of phylogenetic dispersion (PD) and 99 fossil pollen sequences containing 6557 samples/assemblages, we analyse spatio-temporal variation in PD of angiosperms and its relationship with Holocene climate in central Asia. Overall, PD throughout the Holocene decreases linearly with increasing latitude, except for a rise in mean nearest taxon distance from ca. 25 to 35° N. This indicates that phylogenetically divergent taxa decrease progressively with increasing latitude, leaving more phylogenetically closely related taxa in the assemblages, thereby increasing phylogenetic relatedness among the co-occurring taxa. The latitudinal gradient of PD has not been consistent during the Holocene, and this temporal variation is concordant with the Holocene climate dynamics. In general, profound temporal changes in the latitudinal PD toward higher latitudes implies that the major environmental changes during the Holocene have driven considerable spatio-temporal changes in the phylogenetic assembly of high-latitude angiosperm assemblages. Our results suggest that environmental filtering and the tendency of taxa and lineages to retain ancestral ecological features and geographic distributions (phylogenetic niche conservatism) are the main mechanisms underlying the phylogenetic assembly of angiosperms along the climate-latitudinal gradient. Ongoing environmental changes may pose future profound phylogenetic changes in high-latitude plant assemblages, which are adapted to harsh environmental conditions, and therefore are phylogenetically less dispersed (more conservative or clustered).

• MeSH
• biodiverzita MeSH
• fylogeneze * MeSH
• Magnoliopsida * genetika   klasifikace   MeSH
• podnebí MeSH
• pyl genetika   MeSH
• zkameněliny * MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Asie MeSH

Clonal growth of plants is attained by a number of morphologically different organs (e.g. stolons, rhizomes, and roots), which are not functionally equivalent. Consequently, these clonal growth organ (CGO) types can determine functional traits that are associated with clonality, although little is known about their evolutionary flexibility or the constraining role they play on clonal traits. We investigated the rates of evolutionary change by which individual CGOs are acquired and lost using a set of 2652 species of Central European flora. Furthermore, we asked how these individual CGOs constrain functionally relevant clonal traits, such as lateral spread, number of offspring, and persistence of connections. We show that plants can easily switch in evolution among individual types of CGO and between clonal and nonclonal habits. However, not all these transitions are equally probable. Namely, stem-based clonal growth and root-based clonal growth constitute evolutionarily separate forms of clonal growth. Clonal traits are strongly constrained by individual CGO types. Specifically, fast lateral spread is attained by stolons or hypogeogenous rhizomes, and persistent connections are attained by all rhizome types. However, the ease with which clonal organs appear and disappear in evolution implies that plants can overcome these constraints by adjusting their morphologies.

• Klíčová slova
• ancestral states, bud-bearing roots, clonal growth organs, clonal traits, phylogeny, rhizomes, stolons,
• MeSH
• biologická evoluce * MeSH
• buněčné klony MeSH
• fylogeneze MeSH
• Magnoliopsida růst a vývoj   MeSH
• orgánová specificita MeSH
• pravděpodobnostní funkce MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

In the complex process of homeostasis of phytohormones cytokinins (CKs), O-glucosylation catalyzed by specific O-glucosyltransferases represents one of important mechanisms of their reversible inactivation. The CK O-glucosyltransferases belong to a highly divergent and polyphyletic multigene superfamily of glycosyltransferases, of which subfamily 1 containing UDP-glycosyltransferases (UGTs) is the largest in the plant kingdom. It contains recently discovered O and P subfamilies present in higher plant species but not in Arabidopsis thaliana. The cis-zeatin O-glucosyltransferase (cisZOG) genes belong to the O subfamily encoding a stereo-specific O-glucosylation of cis-zeatin-type CKs. We studied different homologous genes, their domains and motifs, and performed a phylogenetic reconstruction to elucidate the plant evolution of the cisZOG gene. We found that the cisZOG homologs do not form a clear separate clade, indicating that diversification of the cisZOG gene took place after the diversification of the main angiosperm families, probably within genera or closely related groups. We confirmed that the gene(s) from group O is(are) not present in A. thaliana and is(are) also missing in the family Brassicaceae. However, cisZOG or its metabolites are found among Brassicaceae clade, indicating that remaining genes from other groups (UGT73-group D and UGT85-group G) are able, at least in part, to substitute the function of group O lost during evolution. This study is the first detailed evolutionary evaluation of relationships among different plant ZOGs within angiosperms.

• MeSH
• Brassicaceae genetika   MeSH
• cytokininy genetika   MeSH
• glukosyltransferasy genetika   MeSH
• Magnoliopsida * genetika   metabolismus   MeSH
• regulace genové exprese u rostlin * MeSH
• rostlinné proteiny genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cytokininy MeSH
• glukosyltransferasy MeSH
• rostlinné proteiny MeSH

BACKGROUND: Involvement of conservative molecular modules and cellular mechanisms in the widely diversified processes of eukaryotic cell morphogenesis leads to the intriguing question: how do similar proteins contribute to dissimilar morphogenetic outputs. Formins (FH2 proteins) play a central part in the control of actin organization and dynamics, providing a good example of evolutionarily versatile use of a conserved protein domain in the context of a variety of lineage-specific structural and signalling interactions. RESULTS: In order to identify possible plant-specific sequence features within the FH2 protein family, we performed a detailed analysis of angiosperm formin-related sequences available in public databases, with particular focus on the complete Arabidopsis genome and the nearly finished rice genome sequence. This has led to revision of the current annotation of half of the 22 Arabidopsis formin-related genes. Comparative analysis of the two plant genomes revealed a good conservation of the previously described two subfamilies of plant formins (Class I and Class II), as well as several subfamilies within them that appear to predate the separation of monocot and dicot plants. Moreover, a number of plant Class II formins share an additional conserved domain, related to the protein phosphatase/tensin/auxilin fold. However, considerable inter-species variability sets limits to generalization of any functional conclusions reached on a single species such as Arabidopsis. CONCLUSIONS: The plant-specific domain context of the conserved FH2 domain, as well as plant-specific features of the domain itself, may reflect distinct functional requirements in plant cells. The variability of formin structures found in plants far exceeds that known from both fungi and metazoans, suggesting a possible contribution of FH2 proteins in the evolution of the plant type of multicellularity.

• MeSH
• aktiny chemie   MeSH
• Arabidopsis chemie   genetika   MeSH
• cytoskeletální proteiny chemie   genetika   MeSH
• fylogeneze MeSH
• konzervovaná sekvence MeSH
• Magnoliopsida chemie   genetika   MeSH
• molekulární modely MeSH
• molekulární sekvence - údaje MeSH
• rostlinné geny * MeSH
• sekundární struktura proteinů MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• terciární struktura proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aktiny MeSH
• cytoskeletální proteiny MeSH

PREMISE: The shoot apical meristem (SAM) is the basic determinant of plant body organization, but interspecific variation in SAM shape and its relationship to stem and leaf morphological traits is not well known. Here we tested the hypothesis that different SAM shapes are associated with specific shoot traits of the plant body and examined the phylogenetic conservatism of these relationships. METHODS: We used geometric morphometrics of SAM outlines for a phylogenetically representative set of 110 herbaceous angiosperms and examined their relationship to a number of shoot traits. RESULTS: We found large variations in SAM shapes across angiosperm lineages, but covering only a subset of geometrically possible shapes. Part of this variation was allometric (due to SAM size), but the dominant shape variation (dome-shaped vs. flat surface) was size-independent and strongly phylogenetically conserved. SAM shapes were largely independent of their cell size and therefore of the number of cells involved. Different patterns in shape variation of outer and inner SAM boundaries were associated with stem thickness, leaf area, and leafiness of the stem. CONCLUSIONS: The findings show that geometric interdependence of meristem zones gives rise to correlations among organ numbers, sizes, and their proportions. Phylogenetic conservatism in these correlations indicates conservatism in regulatory processes that underlie the correlations, or the individual traits, that give rise to plant architecture.

• Klíčová slova
• cell size, genome size, geometric morphometrics, phylogenetic regression, shape allometry,
• MeSH
• fylogeneze MeSH
• listy rostlin MeSH
• Magnoliopsida * MeSH
• meristém * MeSH
• výhonky rostlin MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The monospecific family Mysteriomorphidae was recently described based on two fossil specimens from the Late Cretaceous Kachin amber of northern Myanmar. The family was placed in Elateriformia incertae sedis without a clear list of characters that define it either in Elateroidea or in Byrrhoidea. We report here four additional adult specimens of the same lineage, one of which was described using a successful reconstruction from a CT-scan analysis to better observe some characters. The new specimens enabled us to considerably improve the diagnosis of Mysteriomorphidae. The family is definitively placed in Elateroidea, and we hypothesize its close relationship with Elateridae. Similarly, there are other fossil families of beetles that are exclusively described from Cretaceous ambers. These lineages may have been evolutionarily replaced by the ecological revolution launched by angiosperms that introduced new co-associations with taxa. These data indicate a macroevolutionary pattern of replacement that could be extended to other insect groups.

• MeSH
• biologická evoluce MeSH
• brouci anatomie a histologie   klasifikace   MeSH
• cykasy parazitologie   MeSH
• interakce hostitele a parazita MeSH
• jantar MeSH
• Magnoliopsida parazitologie   MeSH
• paleontologie metody   MeSH
• počítačová rentgenová tomografie MeSH
• zkameněliny MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Myanmar MeSH
• Názvy látek
• jantar MeSH