Explore the vast range of titles available.

The genus Cerastium includes about 200 species that are mostly found in the temperate climates of the Northern Hemisphere. Here we report the complete chloroplast genomes of Cerastium alpinum , C . arcticum and C . nigrescens . The length of cp genomes ranged from 147,940 to 148,722 bp. Their quadripartite circular structure had the same gene organization and content, containing 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. Repeat sequences varied from 16 to 23 per species, with palindromic repeats being the most frequent. The number of identified SSRs ranged from 20 to 23 per species and they were mainly composed of mononucleotide repeats containing A/T units. Based on Ka/Ks ratio values, most genes were subjected to purifying selection. The newly sequenced chloroplast genomes were characterized by a high frequency of RNA editing, including both C to U and U to C conversion. The phylogenetic relationships within the genus Cerastium and family Caryophyllaceae were reconstructed based on the sequences of 71 protein-coding genes. The topology of the phylogenetic tree was consistent with the systematic position of the studied species. All representatives of the genus Cerastium were gathered in a single clade with C. glomeratum sharing the least similarity with the others.

Dehydrin proteins are known to serve a wide variety of intracellular protective functions and enhance the capability of plants to deal with abiotic stresses. The gene for a SK 5 type dehydrin from the arctic chickweed plant Cerastium arcticum (CarDHN) was introduced into tobacco plants. Stress responses of the transgenic plants were evaluated. Compared to the untransformed wild type plants, the CarDHN-expressing plants exhibited improved tolerance to salt and osmotic stress during seed germination and seedling growth, and survived in −10 °C freezing treatment. These CarDHN plants also accumulated lower levels of free proline under salt stress and exhibited lower transcription levels of HSP70 and HSP26 under drought or salt stress, suggesting a possible pleiotropic effect of CarDHN on stress response at cellular or molecular level. However, no significant phenotypic differences were observed between the wild type and the CarDHN-expressing plants under drought stress. Our study demonstrated the specific role of the arctic chickweed dehydrin in tolerance to salt, osmotic and freezing stress.

Climatic warming is associated with organisms breeding carlier in the season than is typical for their species. In some species, however, response to warming is more complex than a simple advance in the timing of all life history events preceding reproduction. Disparities in the extent to which different components of the reproductive phenology of organisms very with climatic warming indicate that not all life history events are equally responsive to environmental variation. Here, we propose that out understanding of phenological response to climate change can be improved by considering entire sequences of events comprising the aggregate life histories of organisms preceding reproduction. We present results of a two-year warming experiment conducted on 33 individuals of three plant species inhabiting a low-arctic site. Analysis of phenological sequences of three key events for each species revealed how the aggregate life histories preceding reproduction responded to warming, and which individual events exerted the greatest influence on aggregate life history variation. For alpine chickweed (Cerastium alpinum), warming elicited a shortening of the duration of the emergence state by 2.5 days on average, but the aggregate life history did not differ between warmed and ambient plots. For gray willow (Salix glauca), however, all phenological events monitored occurred earlier on warmed than on ambient plots, and warming reduced the aggregate life history of this species by 22 days on average. Similarly, in dwarf birch (Betula nana), warming advanced flower bud set, blooming, and fruit set and reduced the aggregate life history by 27 days on average. Our approach provides important insight into life history responses of many organisms to climate change and other forms of environmental variation. Such insight may be compromised by considering changes in individual phenological events in isolation.

The tribe Alsineae is a large monophyletic group in the family Caryophyllaceae especially found across Eurasia and the Americas, but with a center of diversity in the Mediterranean region. Several previous molecular phylogenetic studies have focused on the delimitation of genera and tribes of Caryophyllaceae, especially the subfamily Alsinoideae or the tribe Alsineae in a broader sense than now recognized. However, there are still many open questions regarding the subdivision of the tribe and genus delimitation. In the present study, we sampled 191 (148 species) and 149 (125 species) accessions of Alsineae representing almost all (Adenonema and Pseudocerastium were not available to us) recognized genera in the tribe for nuclear DNA internal transcribed spacer (ITS) and plastid marker rps16 sequences, respectively. A combined matrix of 103 species was built for taxa with both sequences available. Maximum parsimony and Bayesian inference analyses retrieved Cerastium and Stellaria (including Myosoton) as the largest monophyletic genera, while other genera were medium-sized (10–20 spp.) or small (<10 spp.). Our expanded sampling of Pseudostellaria and its relatives suggests a broader circumscription of this genus. Major divergence in morphology, particularly of the seeds, observed in the “Protostellaria”-clade, allows recognition of some taxonomic changes. A total of 16 genera are recognized in Alsineae including Cerastium, Dichodon, Hartmaniella, Holosteum, Lepyrodiclis, Mesostemma, Moenchia, Nubelaria, Odontostemma, Pseudostellaria, Rabelera, Schizotechium, Shivparvatia, and Stellaria, along with Adenonema and Pseudocerastium that could not be analyzed and are, therefore, kept as distinct genera. A diagnostic key to these genera, as well as notes on their relationships, distribution, and nomenclature, is provided.

Cerastium kochianum Iamonico is proposed as a replacement name for C. arvense L. var. strictum W. D. J. Koch (published in 1838) when treated as a species, since C. strictum L., which refers to another taxon (i.e., Arenaria grandiflora L.), is an earlier and validly published name. Cerastium kochianum is related to C. arvense s.l., from which it differs mainly by characters of habit, stem, and leaves and a different chromosome number.

Climate warming has major impacts on seed germination of several alpine species, hence on their regeneration capacity. Most studies have investigated the effects of warming after seed dispersal, and little is known about the effects a warmer parental environment may have on germination and dormancy of the seed progeny. Nevertheless, temperatures during seed development and maturation could alter the state of dormancy, affecting the timing of emergence and seedling survival. Here, the interplay between pre- and post-dispersal temperatures driving seed dormancy release and germination requirements of alpine plants were investigated. Three plant species inhabiting alpine snowbeds were exposed to an artificial warming treatment (i.e. +1·5 K) and to natural conditions in the field. Seeds produced were exposed to six different periods of cold stratification (0, 2, 4, 8, 12 and 20 weeks at 0 °C), followed by four incubation temperatures (5, 10, 15 and 20 °C) for germination testing. A warmer parental environment produced either no or a significant increase in germination, depending on the duration of cold stratification, incubation temperatures and their interaction. In contrast, the speed of germination was less sensitive to changes in the parental environment. Moreover, the effects of warming appeared to be linked to the level of (physiological) seed dormancy, with deeper dormant species showing major changes in response to incubation temperatures and less dormant species in response to cold stratification periods. Plants developed under warmer climates will produce seeds with changed germination responses to temperature and/or cold stratification, but the extent of these changes across species could be driven by seed dormancy traits. Transgenerational plastic adjustments of seed germination and dormancy shown here may result from increased seed viability, reduced primary and secondary dormancy state, or both, and may play a crucial role in future plant adaptation to climate change.

Herbicide-resistant weeds are fast becoming a substantial global problem, causing significant crop losses and food insecurity. Late detection of resistant weeds leads to increasing economic losses. Traditionally, genetic sequencing and herbicide dose-response studies are used to detect herbicide-resistant weeds, but these are expensive and slow processes. To address this problem, an artificial intelligence (AI)-based herbicide-resistant weed identifier program (HRIP) was developed to quickly and accurately distinguish common chickweed plants that are resistant to acetolactate synthase (ALS) inhibitor herbicides and those that are susceptible to ALS inhibitors. A regular camera was converted to capture light wavelengths from 300 to 1,100 nm. Full-spectrum images from a 2-yr experiment were used to develop a hyperparameter-tuned convolutional neural network model using a “train from scratch” approach. This novel approach exploits the subtle differences in the spectral signature of ALS inhibitor-resistant and ALS inhibitor-susceptible common chickweed plants as they react differently to the ALS-inhibiting herbicide treatments. The HRIP was able to identify ALS-inhibitor–resistant common chickweed as early as 72 h after treatment at an accuracy of 88%. It has broad applicability due to its ability to distinguish common chickweed plants that are resistant to ALS-inhibitor herbicides from those that are susceptible to becoming resistant to them regardless of the type of ALS herbicide or dose used. Using tools such as the HRIP will allow farmers to make timely interventions to prevent the herbicide-escape plants from completing their life cycle and adding to the weed seedbank. Nomenclature: common chickweed, Stellaria media (L.) Vill.

Objectives Cerastium davuricum Fisch. ex Spreng. is distributed in European Russia to Mongolia and West Himalaya, and leaves are traditionally used for cooking and drying. Unfortunately, there have not been enough genetic studies on Cerastium until now, which limits understanding of their genetic diversity and the development of further studies. This note reports the plastome sequence of C. davuricum and provides resource for comparative genomics, phylogenetic studies, and molecular markers development within Caryophyllaceae family. Data description Fresh leaves were collected from the Bugant tosgon, Eruu soum, Selenge province (voucher: SE24). The plastid genome library was prepared from the total genomic DNA using the TruSeq DNA Nano Kit along with the NextSeq 500 platform. The genome exhibits a natural quadripartite structure and was 148,318 bp in length. Plastome contains 113 unique genes, including 4 rRNA, 30 tRNA, and 79 protein-coding genes. A total of 26 single-sequence repeats were identified, primarily located in the intergenic spacer regions. Phylogenetic analysis based on the whole plastome shows that Cerastium species formed a monophyletic clade and C. davuricum was first to separate from the ancestor node. This suggests that C. davuricum is the most divergent species within the genus.

Question: How will warming and increased nutrient availability affect individual alpine plant species abundances (non-vascular and vascular) and community composition? Location: Dryas octopetala heath at alpine Finse, southern Norway. Methods: Four years with experimental warming (open top chambers) and nutrient addition. Detrended Correspondence Analysis and Redundancy Analysis were used to examine changes in community composition. GLM-ANOVA was used to examine treatment effects on individual species. Results: Warming alone decreased the abundance of some Carex and bryophyte species, but did not affect community composition. Nutrient addition and warming combined with nutrient addition increased the abundance of high stature species, such as grasses (Festuca spp., Poa alpina) and some forbs (e.g. Cerastium alpinum, Potentilla crantzii). Low stature forbs (e.g. Tofieldia pusilla), a lycophyte (Selaginella selaginoides) and most bryophytes and lichens decreased in abundance. After four years of warming combined with nutrient addition 57% of the mosses, 57% of the liverworts and 44% of the lichens had completely disappeared. Community composition changed significantly, with the largest shift when warming and nutrient addition was combined. Conclusions: Tall species may expand at the expense of low stature species in the alpine region if temperature and soil nutrient content increase. Contrasting responses between grasses and sedges, and species-specific responses within forbs, sedges and shrubs, within and across alpine and arctic sites, suggest that the use of functional types in environmental change research may mask important information on individual species responses. The response of one species within a functional type cannot predict the response of another. Nomenclature: Lid & Lid (1994) for vascular species; Hallingbäck & Holmåsen (1995) for bryophytes; Krog et al. (1994) for lichens.

Stellaria (Caryophyllaceae, tribe Alsineae) is a cosmopolitan genus of herbaceous plants that heretofore has lacked a stable estimate of total number of species. Here, we attempted to sample all species currently recognized under the name Stellaria to determine which belong to a core Stellaria genus versus which are masquerading under this name and are instead more closely related to one of several outgroup lineages. Phylogenetic relationships inferred with RAD loci were recovered with generally high levels of support, regardless of age of specimens (here up to 98 yr) utilized for molecular work. Analyses resolved a monophyletic, core radiation of Stellaria that is sister to Cerastium and others. Within core Stellaria, of which we sampled ca. 87% of species, we recovered five primary lineages. However, current infrageneric hypotheses are incongruous with phylogenomic data, and most morphology-based infrageneric hypotheses break down in light of these results. Outside of core Stellaria we recovered numerous other species currently ascribed to Stellaria that are in need of revised generic placement. Based on current results, however, we propose several new taxonomic and nomenclatural renovations within core Stellaria and external to this group as contribution towards stabilization of generic boundaries in Alsineae. These modifications include description of a new genus of Caryophyllaceae from eastern Asia, Nubelaria, as well description of a new genus, Rabelera, to accommodate the lineage previously and more widely known as Stellaria holostea. Nine new combinations are proposed in the genera Adenonema, Cerastium, Mesostemma, Nubelaria, Rabelera, and core Stellaria. Additionally, one new status, one new synonymy, and lectotypes for four species are proposed. We estimate core Stellaria to consist of approximately 112 species, a decrease from many other published species counts. Our results lay a robust foundation for future evolutionary, phylogenetic, and morphological comparisons within Stellaria and among relatives.