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Aggregate stability (AS) was measured in the 25th year of a long-term organic — conventional comparison field study. Located in southern Manitoba, the study includes two, four-year crop rotations under conventional and organic management, plus a grassland. The forage-grain rotation includes alfalfa (Medicago sativa)–alfalfa–wheat (Triticum aestivum)–flax (Linum usitatissimum). The grain only rotation includes wheat–flax–oat (Avena sativa)–soybean (Glycine max); hairy vetch (Vicia villosa) is substituted for soybean in the organic system. Composted manure was added every 4 yr to half of the organic forage-grain rotation to correct a phosphorus deficiency. The wheat and flax phases were sampled at depths (0–10 cm; 10–20 cm) in spring 2017, and wet aggregate stability was measured using the Yoder method with stacked sieves. Mean weight diameter (MWD) was calculated. AS in the organic systems was never lower than that of comparable conventional systems, but had more large aggregates in only a few cases. Our hypothesis that including alfalfa would increase AS was supported in only a few instances. The largest aggregates (1–2 mm and 2–6.3 mm) and the fewest smallest aggregates (0.25–0.5 mm) were observed in the grassland. For the intermediate aggregate size class (0.5–1 mm), the organic forage-grain systems had levels similar (P > 0.05) to the grassland. While adding manure increased plant growth by about 40% in the organic forage-grain rotation, no AS differences were observed. Limited AS response in the arable systems may be due to suboptimal soil C contents; only the grassland had a C content above the minimum 35 g·kg−1 postulated for Vertisols.

The market success of perennial ryegrass (Lolium perenne L.) cultivars depends on sufficient seed production, as they are propagated by seed. However, breeding for high quality forage production reduces seed yield, and breaking the negative correlation would help to overcome the problem. The foliar disease crown rust is another factor affecting reproductive capacity and thereby seed yield. We evaluated seed yield-related traits and resistance to crown rust in a collection of commercial cultivars and ecotypes of perennial ryegrass and identified genome-wide markers associated with the traits. The study revealed high variation between the ecotype and cultivar groups as well as between years. A genome-wide association study identified 17 DNA single-nucleotide polymorphisms (SNPs) of which eight were associated with crown rust and nine with flag-leaf length. The SNP markers were located within or near predicted genes functioning in defense against pathogens. The identified genes are strong candidates for a further in-depth functional study to continue unravel determination of leaf architecture and crown rust resistance in perennial ryegrass.

Cyanodermella asteris is a fungal endophyte from Aster tataricus, a perennial plant from the northern part of Asia. Here, we demonstrated an interaction of C. asteris with Arabidopsis thaliana, Chinese cabbage, rapeseed, tomato, maize, or sunflower resulting in different phenotypes such as shorter main roots, massive lateral root growth, higher leaf and root biomass, and increased anthocyanin levels. In a variety of cocultivation assays, it was shown that these altered phenotypes are caused by fungal CO2, volatile organic compounds, and soluble compounds, notably astins. Astins A, C, and G induced plant growth when they were individually included in the medium. In return, A. thaliana stimulates the fungal astin C production during cocultivation. Taken together, our results indicate a bilateral interaction between the fungus and the plant. A stress response in plants is induced by fungal metabolites while plant stress hormones induced astin C production of the fungus. Interestingly, our results not only show unidirectional influence of the fungus on the plant but also vice versa. The plant is able to influence growth and secondary metabolite production in the endophyte, even when both organisms do not live in close contact, suggesting the involvement of volatile compounds. [Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Many wild populations are suffering from the loss of genetic diversity caused by habitat fragmentation, while the degree of diversity loss differs among species and populations based on their life history characteristics. Trillium camschatcense, an understory perennial plant, has undergone intensive habitat fragmentation in the Tokachi region, Hokkaido, Japan. Although demographic deteriorations, such as reduced seed production, were already reported, genetic consequences of fragmentation have not been studied with reference to its life history. Here, we examined how life history events (e.g., growth and reproduction) and the stochasticity therein influence genetic diversity in two (each large and small) fragmented T. camschatcense populations. Genetic diversity was evaluated using genome-wide 2,008 single nucleotide polymorphisms (SNPs). In the small population, genetic diversity of newly germinated seedlings was significantly lower than that of matured life history stages, and effective number of breeders (N-b) was smaller than that of the large population. Simulations using a matrix population model showed that the diversity loss at seedlings is caused by genetic drift during reproduction, which was intensified by smaller N-b. Besides, simulations using randomly perturbed transition matrices suggested that stasis at juvenile stages, which is a common characteristics of T. camschatcense, maintains genetic diversity by buffering stochastic decrease, possibly contributing to population viability. While previous studies showed the importance to facilitate reproduction and recruitment for demographic recovery, this study highlighted the crucial roles of juvenile survival in terms of genetic diversity for the conservation of fragmented T. camschatcense populations in the Tokachi region.

Perennial life cycles enable plants to have remarkably long lifespans, as exemplified by trees that can live for thousands of years. For this, they require sophisticated regulatory networks that sense environmental changes and initiate adaptive responses in their growth patterns. Recent research has gradually elucidated fundamental mechanisms underlying the perennial life cycle. Intriguingly, several conserved components of the floral transition pathway in annuals such as Arabidopsis thaliana also participate in these regulatory mechanisms underpinning perenniality. Here, we provide an overview of perennials' physiological features and summarise their recently discovered molecular foundations. We also highlight the importance of deepening our understanding of perenniality in the development of perennial grain crops, which are promising elements of future sustainable agriculture.

The aim of this study was to determine the influence of the different proportion of perennial ryegrass (Lolium perenne L.) in the meadow sward on its fodder value and daily weight gain of Highland cattle. The research was carried out on meadow sward with natural undergrowth that was cultivated by sowing perennial ryegrass. When preparing the sward for sowing, around 40% of it was damaged with a rotary tiller. The sowing rate for perennial ryegrass seeds was varied and amounted to 5, 10 and 15 kg ha−1. As a result, the following treatments of meadow sward were obtained and distinguished: semi-natural sward without sowing as the control, and three experimental treatments with approximately 18, 36 and 55% share of perennial ryegrass in the meadow sward. The animals were kept in a cowshed. In the nutritional part, the impact of feeding the obtained sward on the daily weight gain of Highland bulls and heifers was assessed. The obtained results showed higher gains in both bulls and heifers fed with sward from grasslands with a greater proportion of perennial ryegrass. The weight gain of the animals resulted from the nutrition, i.e. the quality of the feed obtained from the experimental objects. During the control fattening period, the bulls’ average daily weight gain ranged from 649 g to 714 g, while for heifers 556 g to 598 g. Statistical significance (P≤0.05) in body weight gains in both bulls and heifers was shown already at 36% of perennial ryegrass in the meadow sward.

Salinity stress is one of the most important global problems that afflicts and limits the growth and development of turfgrass in arid and semi-arid areas. Therefore, this experiment was conducted to evaluate the effects of the interaction between gamma-aminobutyric acid (GABA) and salinity (NaCl) on perennial ryegrass (Lolium perenne L.). Perennial ryegrass plants were treated with three concentrations of GABA (0, 50, and 100 mM) and NaCl (0, 50, and 100 mM) for two months. Multivariate analysis of variance revealed that GABA, salinity, and their interaction had significant effects on the majority of measured traits. In shoots and roots, the application of salinity increased the Na+/K+ ratio, as well as proline, total soluble carbohydrates and protein (TSP), malondialdehyde (MDA), and hydrogen peroxide (H2O2) content, but reduced relative water content, membrane stability index (MSI), total chlorophyll content, and shoot and root growth. When GABA was applied in saline conditions, Na+ did not accumulate, the Na+/K+ ratio decreased, and the amount of K+ content increased significantly in shoots and roots, thereby allowing plant growth to resume. Peroxidase (POD) and superoxide dismutase (SOD) activities increased significantly (51.83% and 322%, respectively), whereas H2O2 and MDA contents decreased significantly (34.4% and 67%, respectively). In addition, the construction of a biplot, heatmap, and correlation plot fortified the positive effects of GABA on perennial ryegrass growth in saline conditions. GABA may help to alleviate salinity damage through its involvement in osmotic adjustment (proline and TSP), reducing the Na+/K+ ratio and limiting oxidative damage in cells with a dramatic increase in POD and SOD activity. Therefore, the application of GABA is an alternative technique for improving turfgrass tolerance to salinity.

The need for sustainable agricultural practices to meet the food, feed, and fuel demands of a growing global population while reducing detrimental environmental impacts has driven research in multi‐faceted approaches to agricultural sustainability. Perennial cropping systems and microbial biofertilizer supplements are two emerging strategies to increase agricultural sustainability that are studied in tandem for the first time in this study. During the establishment phase of a perennial switchgrass stand in SW Montana, USA, we supplemented synthetic fertilization with a nitrogen‐fixing cyanobacterial biofertilizer (CBF) and were able to maintain aboveground crop productivity in comparison to a synthetic only (urea) fertilizer treatment. Soil chemical analysis conducted at the end of the growing season revealed that late‐season nitrogen availability in CBF‐supplemented field plots increased relative to urea‐only plots. High‐throughput sequencing of bacterial/archaeal and fungal communities suggested fine‐scale responses of the microbial community and sensitivity to fertilization among arbuscular mycorrhizal fungi, Planctomycetes, Proteobacteria, and Actinobacteria. Given their critical role in plant productivity and soil nutrient cycling, soil microbiome monitoring is vital to understand the impacts of implementation of alternative agricultural practices on soil health.

Wildflower strips (WFS) are among the most commonly applied measures to promote pollinators and natural enemies of crop pests in agroecosystems. Their potential to enhance these functionally important insect groups may vary substantially with time since establishment of WFS. However, knowledge on their temporal dynamics remains scarce, hampering recommendations for optimized design and management. We therefore examined temporal dynamics of taxonomic and functional groups of bees and hoverflies in perennial WFS ranging from one to ≥6 years since sowing with a standardized species-rich seed mixture of flowering plants in 18 agricultural landscapes in Switzerland. The abundance of wild bees, honeybees and hoverflies declined after the second year by 89%, 62% and 72%, respectively. Declines in bee abundance and hoverfly species richness were linear and those of aphidophagous hoverflies exponential, while wild bee species richness peaked in the third year. Declines over time generally paralleled decreases in flower abundance (-83%) and flowering species richness (-61%) and an increase in grass cover (+70%) in WFS. Flowering plant species richness showed strong positive relationships with dominant crop-visiting wild bees and aphidophagous hoverflies. Furthermore, dominant crop-visiting wild bees, but not aphidophagous hoverflies, were positively related to the proportion of (semi-)open semi-natural habitat in the surrounding landscape (500 m radius), but negatively with forest. We conclude that the effectiveness of perennial WFS to promote pollinator diversity, crop-pollinating bees and aphidophagous hoverflies through foraging resources decreases after the first two to three years, probably due to a decline of diverse and abundant floral resources. Although older perennial WFS may still provide valuable nesting and overwintering opportunities for pollinators and natural enemies, our findings indicate that regular re-sowing of perennial WFS may be necessary to maintain adequate floral resource provisioning for effective pollinator conservation and promotion of crop pollination and natural pest control services in agricultural landscapes.

To reduce the severity of shoot blight and prevent the resulting development of cankers on perennial apple wood, we evaluated eight fire blight postinfection spray programs of prohexadione-calcium (PCA) alone or with acibenzolar-S-methyl (ASM) over 2 years. On mature trees of cultivar Royal Court, a single application of the high PCA rate (247 mg/liter) at 2 to 3 days after inoculation resulted in 89.5 and 69.5% reduction of shoot blight severity after inoculation. Two applications of PCA 247 mg/liter 12 or 14 days apart, with the first one applied 2 to 3 days after inoculation, resulted in 78.8 and 74.5% reduction of shoot blight severity in both years. A 100% control of canker incidence on perennial wood from infected shoots in both years was achieved with a single application of PCA (247 mg/liter) applied at 2 or 3 days after the inoculation, and three applications of PCA (125 mg/liter) + ASM (25 mg/liter) 12 to 16 days apart reduced canker incidence by 83.5 and 69% in the 2 years. The other programs with lower PCA rates and frequencies of application reduced shoot blight severity 50.8 and 51.8% (PCA) and 62.6 to 72% and 59.3% (PCA + ASM) over 2 years, respectively. Reduction of canker incidence on wood by the other programs was 66.5% and 69 to 90.4% in the two years, respectively. As fire blight cankers lead to death of dwarf apple trees and serve as primary sources of inoculum, our effective PCA and PCA + ASM programs could serve as viable postinfection management options. These treatments can reduce or prevent canker development and thus significantly abate tree losses in high-density apple orchards after fire blight epidemics occur. Accepted version

The main objectives of this study were to determine the floristic composition of the vegetation cover and to find the effects of wastewater pollution on the plant community structure in eastern Saudi Arabia. 28 stands which were distributed among polluted and unpolluted sites, were chosen for this study. A total of 42 plant species were recorded (14 in the polluted and 28 in the unpolluted sites). The recorded plants comprised of 13 perennial plant species and 29 annual plant species. Seven vegetation communities were determined using TWINSPAN and DCA classification and ordination techniques. Three in the polluted sites, two in the unpolluted sites and the remaining two were mixed communities. The (Sarcopoterium spinosum – Pistacia len‐tiscus) community in the polluted sites, had the highest values of soil moisture, salinity, sulphate, calcium and potassium. On the other hand, Juniperus phoenicea – Olea europaea community in the unpolluted site, had the lowest value of organic matter, salinity and magnesium. In respect of genetic diversity, the community of Foeniculum vulgare - Nicotiana glauca in the unpolluted site, was the most diverse, while Ricinus communis - Chrysanthemum coronarium in the polluted sites was the least one. Both soil and wastewater heavy metal analysis indicated that Pb, Cd, Cr, Cu and Ni concentrations in the polluted sites were significantly higher than those in the unpolluted ones. The impact of wastewater discharge led to the appearance of new invasive plant species that may significantly affect plant diversity and community structure in eastern Saudi Arabia. Finally wastewater discharge in open rangelands could adversely affect the growth of plant species in the rangelands and thus adversely affect plant community structure and diversity.

Population irruptions of the western Pacific crown-of-thorns sea star (Acanthaster sp.) are a perennial threat to coral reefs and may be initiated by fluctuations in reproductive or settlem...

Salsola drummondii is a perennial habitat-indifferent halophyte growing in saline and non-saline habitats of the Arabian hyperarid deserts. It offers an invaluable opportunity to examine the molecular mechanisms of salt tolerance. The present study was conducted to elucidate these mechanisms through transcriptome profiling of seedlings grown from seeds collected in a saline habitat. The Illumina Hiseq 2500 platform was employed to sequence cDNA libraries prepared from shoots and roots of non-saline-treated plants (controls) and plants treated with 1200 mM NaCl. Transcriptomic comparison between salt-treated and control samples resulted in 17,363 differentially expressed genes (DEGs), including 12,000 upregulated genes (7870 in roots, 4130 in shoots) and 5363 downregulated genes (4258 in roots and 1105 in shoots), and 272,643 unigenes were functionally annotated. The majority of identified DEGs are known to be involved in transcription regulation (79), signal transduction (82), defense metabolism (101), transportation (410), cell wall metabolism (27), regulatory processes (392), respiration (85), chaperoning (9), and ubiquitination (98) during salt tolerance. This study identified potential genes associated with the salt tolerance of S. drummondii and demonstrated that this tolerance may depend on the induction of certain genes in shoot and root tissues. These gene expressions were validated using reverse-transcription quantitative PCR, the results of which were consistent with transcriptomics results. To the best of our knowledge, this is the first study providing genetic information on salt tolerance mechanisms in S. drummondii. This article is protected by copyright. All rights reserved.

Masting, the synchronous, highly variable flowering across years by a population of perennial plants, has been reported to be precipitated by various factors including nitrogen levels, drought conditions, and spring and summer temperatures. However, the molecular mechanism leading to the initiation of flowering in masting plants in particular years remains largely unknown, despite the potential impact of climate change on masting phenology. We studied genes controlling flowering in the alpine snow tussock Chionochloa pallens (Poaceae), a strongly masting perennial grass. We used a range of in situ and manipulated plants to obtain leaf samples from tillers (shoots) which subsequently remained vegetative or flowered. Here, we show that a novel orthologue of TERMINAL FLOWER 1 (TFL1; normally a repressor of flowering in other species) promotes the induction of flowering in C. pallens (hence Anti-TFL1), a conclusion supported by structural, functional and expression analyses. Global transcriptomic analysis indicated differential expression of CpTPS1, CpGA20ox1, CpREF6 and CpHDA6, emphasizing the role of endogenous cues and epigenetic regulation in terms of responsiveness of plants to initiate flowering. Our molecular-based study provides insights into the cellular mechanism of flowering in masting plants and will supplement ecological and statistical models to predict how masting will respond to global climate change.

Pale swallowwort [Vincetoxicum rossicum (Kleopow) Barbar.; syn.: Cynanchum rossicum (Kleopow) Borhidi] and black swallowwort [Vincetoxicum nigrum (L.) Moench; syn.: Cynanchum louiseae Kartesz & Gandhi] are invasive perennial viny milkweeds that have become prevalent across natural and managed habitats in northeastern North America. Southern blight of V. rossicum caused by the fungus Athelia rolfsii (Curzi) C. C. Tu & Kimbr. was reported at a New York county park in 2008, resulting in a decline in V. rossicum stands. The disease outbreak and persistence of the pathogen highlighted the potential of A. rolfsii for Vincetoxicum spp. control. To better characterize A. rolfsii’s pathogenicity and biology, we studied virulence to adult Vincetoxicum spp., spatiotemporal attributes of the Southern blight epidemic at the discovery site over 4 yr, and sclerotial survival over 2 yr. Disease incidence and severity were high for both Vincetoxicum spp. in misting chamber experiments. The spatiotemporal spread patterns of Southern blight in V. rossicum suggest the epidemic in the first year of monitoring (2016) was already highly aggregated and that subsequent spread was limited and resulted in significant local aggregation. Sclerotial survival studies at two locations (Pittsford and Ithaca, NY) demonstrated the A. rolfsii isolates can overwinter in upstate New York and are pathogenic to Vincetoxicum spp. the subsequent season. However, shallow burial of sclerotia more rapidly reduced survival compared with placement on the soil surface. Overwinter survival of A. rolfsii sclerotia in New York is notable, as this pathogen is typically associated with subtropical and tropical regions. Broadcast applications of the pathogen would be needed for widespread Vincetoxicum control at a site, but even restricting releases to select locations would not prevent pathogen movement off-site via water or machinery. The known risks of the A. rolfsii isolate to other broadleaf plants in natural and agricultural settings suggest a low feasibility of use for the biological control of Vincetoxicum spp.

Reproductive success largely defines the fitness of plant species. Understanding how heat and drought affect plant reproduction is thus key to predicting future plant fitness under rising global temperatures. Recent work suggests reproductive tissues are highly vulnerable to water stress in perennial plants where reproductive sacrifice could preserve plant survival. However, most crop species are annuals where such a strategy would theoretically reduce fitness. We examined the reproductive strategy of tomato (Solanum lycopersicum var. Rheinlands Ruhm) to determine whether water supply to fruits is prioritized above vegetative tissues during drought. Using optical methods, we map xylem cavitation and tissue shrinkage in vegetative and reproductive organs during dehydration to determine the priority of water flow under acute water stress. Stems and peduncles of tomato showed significantly greater xylem cavitation resistance than leaves. This maintenance of intact water supply enabled tomato fruit to continue expanding during acute water stress, utilising xylem water made available by tissue collapse and early cavitation of leaves. Here, tomato plants prioritize water supply to reproductive tissues, maintaining fruit development under drought conditions. These results emphasize the critical role of water transport in shaping life history and suggest a broad relevance of hydraulic prioritization in plant ecology. This article is protected by copyright. All rights reserved.

Context Perennial forage grass species are often grown with limited water following establishment and rely on accessing water deep in the soil profile to survive. Aim This study aimed to characterise bermudagrass (Cynodon spp.) genotypes with rapid vertical root growth associated with post-establishment survival. Methods Twelve bermudagrasses representing genotypes from diverse climate zones in Australia were established in rhizotrons to analyse the stability in genotypic variation in root and shoot growth in winter and summer experiments. Genotypic rank of root length, leaf area, and root dry weight were consistent in both seasons. Key results Bermudagrass genotypes exhibited different traits correlated with root vertical growth rate and inconsistency of genotypic rank of shoot growth. During winter establishment, the rate of root depth development (RRDD) (r = −0.64) was correlated with the proportion of root length that became inactive, that was likely due to seasonal root death in winter conditions; during summer establishment, RRDD was correlated with tiller appearance rate (r = 0.45) and root distribution to 10 cm depth (r = −0.62). Shoot dry weight was correlated with photosynthesis (r = 0.85) and transpiration (r = 0.79) in summer, but not in winter. RRDD (r = 0.75, winter and r = 0.77, summer) was correlated with drought resistance index, previously analysed under field conditions. Conclusions and implications Genotypes from the Mediterranean climates in Australia showed rapid growth of roots and shoots in both seasons and have the greatest potential for broader application for forage production in variable environments.

The research aimed to study the combined effect of inter-row sodding with perennial grasses and biofertiliser applications (microbial preparations, MPs) on soil fertility and biological activity, as well as on mineral nutrition, productivity and quality of grapes. The experiment was conducted at a vineyard of the Shasla x Berlandieri 41B-rootstock Muskat Belyy variety nearby Sevastopol. The two-factor design was as follows. Sodding: with segetal vegetation (SV) or a mixture of seeded cereal and leguminous herbs (MHs). Microbial preparations: grapevine root system and soil bacterisation with MPs of various action, including Diazophyte nitrogen fixer, Phosphoenterin (PE) phosphate-mobiliser and a complex of microbial preparations (CMP) additionally containing Biopolycide bioprotector. In control, MPs were not applied with SV or MH sodding. Preparations were introduced in soil once a year prior to grapevine flowering at a dose of 200 g MP suspension per bush. Herbs were mown 5–6 times per season at 30–40 cm height. A combined sodding—MPs usage has been found to increase the nitrate content by 24–45, mobile P2O5 – by 16–21, exchangeable K2O – by 28–50 and organic matter – by 0.06–0.13 % relative to control. The greatest increase in N-NO3–K2O content was registered for the combination of MHs, Diazophyte and CMP; combined SV—CMP–MHs had the greatest impact on mobile P2O5 and organic matter. Biologisation enriched mineral grapevine nutrition, especially for P and K, as well as increased the bush productivity by 10–14 % (maximum in CMP–MHs) via improving the berry and bunch mass and grape quality via significantly increasing the sugar content and lowering acidity of wort. MHs–CMP maximized counts of agronomically valuable microorganisms involved in the organic and mineral nitrogen and phosphorus turnover (ammonifiers and oligotrophs by 120–130, amylolytics and phosphate mobilisers by 50–70 and oligonitrophilic by 50– 80 %). All usages contributed to soil enrichment with nutrients and humus.

Grafting technology in vegetable crops is becoming increasingly popular as an alternative tool to improve the biotic and abiotic resistance besides improvement in horticultural traits. By utilizing the right combination of resistant rootstock and scion, desired variability can be achieved to improve the yield and quality of vegetables. A study was conducted at the College orchard, Department of Vegetable science, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore during the year 2020-2021 to evaluate the graft compatibility with two chilli rootstocks. The experimental material consisted of two perennial rootstocks viz., CC-CBE-001 and CF-CBE-007 and three scion materials viz., TNAU Chilli Hybrid CO 1, Ranga hybrid and Bangaram hybrid. Wedge grafting was done using 60 days old rootstock and 45 days old scion seedlings with nine treatments. The adhesion line wall thickness of pith cells were determined at different stages after grafting. The wound healing of the scion-rootstock union was studied using microscopic examination of the grafting region on the 5th, 10th, 15th and 20th day after grafting. It was observed that ten days after grafting, vascular bundle was formed and a large amount of callus was produced to bridge the scion and rootstock. Despite interspecific grafting, callus formation, subsequent cell differentiation and vascular connection were established, resulting in effective graft compatibility, according to the anatomical and histological analysis.

Little is known about phosphorus (P) uptake at deep soil layers, e.g. below 1 m of soil depth. We aimed at tracing P uptake up to 4.2 m of soil depth of different plant species in an arable field using 33P isotope combined with the core-labelling technique. Soil was packed into ingrowth-cores and labelled with H3 33PO4. The ingrowth cores were placed into field plots of intermediate wheatgrass, perennial lupine, rosinweed and curly dock at the depths of 0.2, 1.0, 2.5 and 4.2 m. 33P uptake into shoots was measured by liquid scintillation assay after 4, 6 and 8 weeks of labelling. Root-length and diameter classes were analyzed from the retracted ingrowth-cores. We observed 33P uptake from all the tested soil depths down to 4.2 m. Curly dock with higher root density exhibited greater 33P uptake. Roots below 1 m was responsible for nearly 50 % of the total 33P uptake from all four depth-levels. Also, roots below 1.0 m showed higher 33P concentration per unit root mass, in line with a higher proportion of fine roots at depth. Our data demonstrate that perennial crop species can access deep P beyond 4 m of soil depth, and that the share of total P uptake below topsoil layers can be substantial, possibly related to the shift towards finer roots in deep soil layers. The results also show that the capacity for deep P acquisition highly depends on crop species even under same field conditions. Therefore, future research should focus on identifying crops with efficient P acquisition capacity in deeper soil layers which can potentially improve crop P access, especially under P-limited conditions in the topsoil.

An appropriate resource-use strategy contributes to the invasion success of exotic plants. During range expansion, population density and nitrogen availability are two important factors that exert significant influences on resource-use-associated traits. As population density decreases and resource availability increases, invasive species are likely driven to be increasingly quicker in resource-use return. By far, it remains unclear how resource-use-related traits shift in response to simultaneous changes in population density and N deposition, and how the shift in resource-use strategy is related to growth in invasive plants. Here we investigated the intraspecific variation in growth and leaf-level resource-use-related traits across invasive populations of different covers under contrasting N levels using a worldwide invasive perennial vine, Mikania micrantha. N addition greatly increased the growth and leaf physiological parameters of M. micrantha. At low N level, the resource-use strategy shifted to be more conservative with decreasing population cover, which was primarily correlated with increasing leaf investment; at high N level, on the contrary, the resource-use strategy shifted to be more acquisitive, which was primarily correlated with increasing carbon assimilation capacity. In addition, M. micrantha growth performance was less related to population cover, and it did not associate with leaf physiology. These results suggest that resource-use strategy shifts from conservative to acquisitive towards range edges during range expansion of M. micrantha. This work reveals the pattern of resource-use strategy in long-term plant invasion, and can provide insights into how invasive species will fare in the context of nitrogen deposition.

Winter dormancy (WD) is a crucial strategy for plants coping with potentially deadly environments. In recent decades, this process has been extensively studied in economically important perennial eudicots due to changing climate. However, in evergreen monocots with no chilling requirements, dormancy processes are so far a mystery. In this study, we compared the WD process in closely related evergreen (Iris japonica) and deciduous (I. tectorum) iris species across crucial developmental time points. Both iris species exhibit a ‘temporary’ WD process with distinct durations, and could easily resume growth under warm conditions. To decipher transcriptional changes, full-length sequencing for evergreen iris and short read RNA sequencing for deciduous iris were applied to generate respective reference transcriptomes. Combining results from a multipronged approach, SHORT VEGETATIVE PHASE and FRUITFULL (FUL) from MADS-box was associated with a dormancy- and a growth-related module, respectively. They were co-expressed with genes involved in phytohormone signaling, carbohydrate metabolism, and environmental adaptation. Also, gene expression patterns and physiological changes in the above pathways highlighted potential abscisic acid and jasmonic acid antagonism in coordinating growth and stress responses, whereas differences in carbohydrate metabolism and reactive oxygen species scavenging might lead to species-specific WD durations. Moreover, a detailed analysis of MIKCCMADS-box in irises revealed common features described in eudicots as well as possible new roles for monocots during temporary WD, such as FLOWERING LOCUS C and FUL. In essence, our results not only provide a portrait of temporary WD in perennial monocots but also offer new insights into the regulatory mechanism underlying WD in plants.

Purpose In cold climates, glyphosate residues may linger in soils, with effects on plant–microbe interactions and, consequently, plant performance. Here, we explore the influence of glyphosate residues on the endophytic microbiota (bacteria and fungi) and performance of the perennial nitrogen-fixing weed Lupinus polyphyllus. Methods In a common garden, we grew plants from six populations of L. polyphyllus in glyphosate-treated or untreated control soils, with or without additional phosphorus. We sampled plant microbiota (leaves, roots, nodules) and assessed plant performance based on six traits: height, retrogression probability (i.e. shrinkage), biomass, root:shoot ratio, nodule number, and nodule viability. Results The richness of plant endophytic microbial communities was determined by soil phosphorus level rather than by glyphosate treatment. However, for bacteria, the composition of these communities differed between glyphosate-treated and control soils across plant tissue types; no difference was observed for fungi. The plant bacterial communities in both soil types were dominated by potential nitrogen-fixing bacteria belonging to family Bradyrhizobiaceae, and particularly so in glyphosate-treated soils. Overall, though, these changes in plant bacterial communities had a minor effect on plant performance: the only difference we detected was that the probability of retrogression was occasionally higher in glyphosate-treated soils than in control soils. Conclusion Our findings indicate that glyphosate-based herbicides, when applied at the recommended frequency and concentration, may not have critical effects on the growth of short-lived weeds after the safety period has passed; however, the endophytic microbiota of such weeds may experience longer-lasting shifts in community structure.

Relevance. The article presents the materials of the geobotanical examination of the virgin steppes of the Western Predcaucasia. The relevance of the study is due to the modern state of natural grass stand, which is under constant anthropogenic influence.Methods. The research points are located in the southwestern part of the Stavropol Territory and the northeastern part of Karachay-Cherkessia, within the absolute heights of 500–880 m. The description of vegetation and its analysis was carried out on ten accounting sites (10x10 m) according to methods generally accepted in geobotany.Results. It was revealed that in the grass stand the grass familyhas on average 17,5% (its weight fraction is 70–80%). In the formation of grass stand plant associations, the leading role belongs to the dominant sod steppe-grasses: Stipa pulcherrima, Festuca valesiaca, Festuca rupicola, Bothriochloa ischaemum, etc. Legumes (Medicago romanica, Trifolium pratense, Onobrychis arenaria) are the main source of protein for animals, they are diverse and have on average 10,8%, but in weight terms they are inferior to sod steppe-grasses. The flora of the studied steppes is represented by a number of economically valuable plants. These are sod steppe-grasses — the creators of the main feed mass of the steppe. They are also sources of a protein component for animals. But the main source of protein in the steppe grass stands are representatives of the legume family (species Trifolium, Medicago, Onobrychis, etc.). Nectariferous plants (Filipendula vulgaris, Galium ruthenicum, Echium russicum) and drug plants (Adonis vernalis, Glycyrrhiza glabra, Thymus marschallianus, etc.) are found in the steppe. The spectrum of life cycles of the flora is noteworthy. There is a high percentage of perennials — from 66,7 to 97,8%. This fact indicates that the axes of ecological niches are packed relatively tightly by perennials — persistent competitors of annual plants (more often weeds). Until mid-summer the generative stage of development of wild plant species reaches on average 80%. Their gene pool can be recommended for the restoration of low-productive steppe grass stand, as well as for use in selection work.

A new direction in pre-sowing seed preparation is environmentally friendly and energyefficient ultraviolet irradiation, which increases germination, reduces seed infection, and improves growth force. In this regard, the experiment of studying the effect of UV irradiation on the sowing qualities and morphophysiological parameters of the seeds of the birds-foot trefoil and awnless brome was laid at the UdmFRC UB RAS in 2019. Use of UV rays of range A with a wavelength of 315–400 nm for 5 min reduced the infection of the birds-foot trefoil seeds by 3.2%, increased the length of the sprout by 0.81 cm and the strength of growth — by 5.4% in comparison with untreated seeds. There was also a tendency for a decrease in seed hardness by 2.5%, an increase in root length by 0.41 cm, and the degree of seedling development by 0.12 points. The most effective for awnless brome seeds was UV treatment for 35 minutes, which led to an increase in germination by 14.5%, a decrease in seed infection by 5.8%. There was also a tendency to improve the morphological parameters of seedlings: the length of the sprout increased by 0.9 cm, the length of the root — by 0.88 cm, the length of the coleoptile — by 0.30 cm. The strength of growth in this variant was 9.3% higher than in the control without treatment. In general, the treatment of perennial grasses seeds with ultraviolet light reduced infection, increased laboratory germination and strength of growth, and reduced seed hardness.

This study of Astragalus holmgreniorum examines its adaptations to the warm desert environment and whether these adaptations will enable it to persist. Its spring ephemeral hemicryptophyte life‐history strategy is unusual in warm deserts. We used data from a 22‐year demographic study supplemented with reproductive output, seed bank, and germinant survival studies to examine the population dynamics of this species using discrete‐time stochastic matrix modeling. The model showed that A. holmgreniorum is likely to persist in the warm desert in spite of high dormant‐season mortality. It relies on a stochastically varying environment with high inter‐annual variation in precipitation for persistence, but without a long‐lived seed bank, environmental stochasticity confers no advantage. Episodic high reproductive output and frequent seedling recruitment along with a persistent seed bank are adaptations that facilitate its survival. These adaptations place its life‐history strategy further along the spectrum from “slower” to “faster” relative to other perennial spring ephemerals. The extinction risk for small populations is relatively high even though mean λ s > 1 because of the high variance in year quality. This risk is also strongly dependent on seed bank starting values, creating a moving window of extinction risk that varies with population size through time. Astragalus holmgreniorum life‐history strategy combines the perennial spring ephemeral life form with features more characteristic of desert annuals. These adaptations permit persistence in the warm desert environment. A promising conclusion is that new populations of this endangered species can likely be established through direct seeding., We used a 22‐year demographic dataset to produce a matrix population model for Astragalus holmgreniorum, an endangered Mojave Desert perennial with an unusual life‐history strategy. We demonstrated that the species depends on a stochastic environment for persistence. Favorable years permit high seed production and high recruitment success, while unfavorable years are tolerated through the existence of a long‐lived seed bank. This perennial spring ephemeral is short‐lived and has many life‐history features in common with desert annuals, increasing its probability of survival in the warm desert environment.

There are few side-by-side comparisons on how Kentucky bluegrass (Poa pratensis L.) invasion has affected plant diversity and carbon (C) and nitrogen (N) dynamics. Between 2013 and 2015, four plots (4.9 × 4.9 m) were annually located on a long-term (1916−2016), moderately stocked pasture at the Northern Great Plains Research Laboratory (USDA-ARS) near Mandan, North Dakota. All plots were located on loamy ecological with minimal microsite differences. Each site had areas that were visually observed to have the largest vegetative component dominated by either Kentucky bluegrass (KBG) or dominated by other species (CONT). Two 1/8 m2 quadrats were clipped by species, including detached plant material (litter), within each subplot between mid to late July 2013, 2014, and 2015. This period represents peak biomass production and offers the best opportunity to capture cool- and warm-season perennial species. In 2013, soil samples were taken at depths of 0−5, 5−10, and 10−20 cm within each plot and thatch samples were hand excavated after clipping. Carbon and N were determined on biomass, litter, thatch, and soil samples. KBG plots produced 28% more biomass annually than the CONT plots. In 2014 and 2015, species richness was 0.7−2.1 × greater in the CONT plots. Although N and C concentrations were similar between treatments for aboveground biomass, litter, and thatch when expressed on a g m−2 basis, N was 34% greater for aboveground biomass and 600% greater for litter in KBG plots. Soil organic C and total soil N at 0−5 cm were 26% and 22% greater in KBG plots, respectively. Our findings indicate that KBG plots had less diversity and greater aboveground and belowground N and C than CONT. More follow-on research is needed to understand how C and N stocks and dynamics influence Kentucky bluegrass invasion.

International audience; Pollination is an essential ecosystem service for pollinator-dependent crops and plant communities. Apis mellifera L. is by far the most commonly used species to obtain this service in agriculture. However, there is growing evidence of the importance for crop yields of the service provided by wild bees and non-bee insect pollinators. Establishing flower resources in agricultural landscapes is a management practice that can increase insect pollinator populations and improve crop yields. We established perennial native flower strips (NFS) in four avocado orchards in central Chile during autumn 2017. We monitored flower visitors and counted newly formed fruits in avocados near and far from NFS in spring 2019, to assess flower visitor groups, flower visitation rates and fruit numbers. Only A. mellifera visited avocado flowers within bees, whereas both the managed A. mellifera and wild bees were the main visitors to the NFS. NFS increased visitation rates to adjacent avocado of flies, and with a trend for the sum of all non-managed flower visitors (i.e. excluding A. mellifera). However, there were no differences in the rates of A. mellifera visitation to avocados near and far from NFS. Avocado fruit numbers were higher among avocados near NFS than among those farther away. This difference could be due to better pollination by the increased visits to avocado flowers by flies or other wild insects. Therefore, NFS could contribute to crop fruit number, as well as conservation of native flora, wild bees and non-bee pollinators on fruit farms in the "Central Chile" biodiversity hotspot.

Green roofs are known to mitigate the negative effects of urban consolidation by offering diverse ecosystem functions compared to non-vegetated roofs. However, the support for native biodiversity might be improved by using native plant species. In a mesocosm experiment, we studied the suitability of three commercial green-roof growth substrates for the establishment of 27 native plant species from dry sandy grasslands of northwestern Germany over the course of four years. The substrates were mineral-based, but differed in the layering of organic matter. Total establishment rates reached 44–59% in Year 4, indicating the general suitability of the substrates. During the first weeks after seeding, with light irrigation, the vascular plant cover was greater in the similar substrates Zincolit® Plus (Z) and Zincolit® Plus-Leicht (ZL) with their compost-based organic mulch layers than in the substrate Sedumteppich (ST) with its organic matter evenly admixed with the mineral aggregates. In Years 2 and 3, however, the vascular plant cover was greater in the ST substrate, likely due to the better availability of water and nutrients from the organic matter compared to the dry surface-mulch layer variants Z and ZL. After severe drought events, the decline in plant cover was more pronounced in the ST substrate, likely representing a trade-off between lush growth and a susceptibility to drought. An indicator-species analysis revealed differences in species composition between the ST and Z/ZL substrates. Annual plant species were indicators of the ST substrate. Perennials, such as Thymus pulegioides and Achillea millefolium, were typical of the Z and ZL substrates. In addition to the general suitability of the tested standard substrates for target species establishment, the study indicated that a combination of different layers of substrate components resulted in different vegetation patterns that may have a positive effect on green-roof biodiversity.