Perennial Research Articles

SESELI LIBANOTIS (L.) W.D.J. KOCH (APIACEAE): CHEMICAL COMPOSITION OF ESSENTIAL OILS, THEIR ANTIBACTERIAL AND CYTOTOXIC ACTIVITIES

Introduction. Infectious diseases and cancer remain among the leading causes of death worldwide. In this regard, the search for biologically active molecules from among synthetic and natural compounds for the purpose of creating medicines remains an urgent task of modern science. Plants that have impressive natural and biotechnological resource potential, taking into account modern advances in the field of ex situ, in situ and in vitro cultiva-tion, remain a promising source of native substances. One of the promising sources of biologically active substances is a perennial plant, the Seseli libanotis (L.) W.D.J. Koch, Apiaceae, growing in central, eastern Europe and Asia in dry pastures and forest edges. The main components of the genus Seseli L. are furo- and pyranocoumarins, essential oils and polyacetylene compounds, which exhibit antibacterial, antifungal, insecticidal, diuretic, antiviral, anti-inflammatory, and antitumor properties. The aim – study of the chemical composition, antibacterial and cytotoxic activities of S. libanotis roots essential oil. Material and methods. The roots were collected in places of natural growth in September 2022, during the fruiting period (Irkutsk region, Maloye Goloustnoye village). The voucher specimen is stored in the herbarium of the Institute of Ecological Ecology SB RAS (UUH 020438). Obtaining essential oils. Essential oils were obtained by hydrodistillation. The qualitative composition and quantitative content of essential oil compo-nents were studied by GC/MS. The study of the antibacterial activity of essential oils was carried out in vitro on test cultures of gram-positive and gram-negative bacteria (Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, Pseudomona saeruginosa, Salmonella enterica) using the disc diffusion method. Cell viability assay was performed on HeLa cell lines using trypan blue. Results. The composition and quantitative content of the components of essential oils of the roots of S. libanotis of the Baikal flora were studied for the first time. 28 components of predominantly monoterpene nature have been identified, the main ones being limonene (57,60%), α-pinene (6,88%), cis-β-ocimene (6,75%). Also found were fatty acids, polyacetylene-falcorinol and 7-isopen-tinyloxycoumarin. Essential oils of S libanotis have antibacterial activity against gram-positive bacteria Staphylococcus aureus, Streptococcus pyogenes and gram-negative bacteria Escherichia coli. Cultivation of Hela with S. libanotis essential oils resulted in decreased viability in the concentration range of 0.04–2.56 μL/mL for 72 hours. Conclusions. Essential oils of roots of S. libanotis, with high yield, containing falcarinol and coumarin, have antibacterial and cytotoxic activity.

Effect of post-harvest drying period on the chemical composition of Zingiber zerumbet Sm. Rhizomes essential oil and its biological activities.

Zingiber zerumbet Sm. (Family: Zingiberaceae) is an important perennial medicinal oil-bearing herb that is native to the Southeast Asia. This study examines the impact of different durations of post-harvest shade drying (ranging from 1 to 12months) on essential oil yield and chemical composition of Z. zerumbet, in comparison to the freshly collected oil sample. This study explores how post-harvest shade drying impact the composition and longevity of Z. zerumbet rhizomes as well as its antimicrobial, antibiofilm activity. The oils were analyzed for their chemical composition analysis using a gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The post-harvest periods of drying (1-12months) were discovered to enhance the concentration of marker constituents in the oil. The primary constituent, Zerumbone, was detected in concentrations ranging from 69.38 ± 5.63% to a maximum of 80.19 ± 1.53% as the drying duration of the rhizome was extended. The output of the essential oil was not significantly affected by drying times; however, it did have a noticeable impact on the proportions of monoterpenes. Both disc diffusion and broth microdilution assay were used in freshly collected Z. zerumbet oil for its antimicrobial potential against S. aureus, L. monocytogens, S. hominis, Salmonella enterica serovar Typhimurium, P. aeruginosa, S. intermedius, E. coli, and C. albicans. For the first time, the oil reported to exhibit antibiofilm activity against S. aureus which was validated using fluorescence microscopy, and effectively disrupts the biofilm by 47.38% revealing that essential oil was able to disintegrate the clusters of the pathogen. Z. zerumbet rhizome oil is effective to reduce food-borne microorganisms. Therefore, its essential oil, a natural source of bioactive zerumbone, may improve flavor, aroma, and preservation.

Cell wall composition and nutritional quality through seasons of the saltgrass Distichlis laxiflora growing in halophytic and mesophytic meadows

The genus Distichlis comprises halophytic perennial C4 grasses which grow in very extreme conditions. It is distributed throughout almost the entire American continent. Despite these interesting characteristics, studies on these plants are relatively scarce, and their ecological and productive value deserves to be further explored. In this work, nutritional aspects, and composition of the cell walls of the aerial part (leaves and shoots) of D. laxiflora Hack were studied. Their changes over four samplings in different seasons, in two nearby sites: a halophytic meadow (H), and a mesophytic meadow (M), were analyzed. Photosynthetic efficiency and K/Na ratio were determined as stress indicators. Plants of sites H and M have similar cell wall content except for spring when plants from site H show lower values. Also, the spring samples present a markedly higher in vitro digestibility for site H. In agreement, samples from site H contain lower amounts of glucuronoarabinoxylans and β-glucans. The protein content is lower in site H, except for spring, and with a maximum in summer for site M. This work shows some changes in the cell walls of D. laxiflora in response to salinity, and these changes influence the digestibility of this material. Spring, coinciding with the regrowth cycle of this plant and with the worst stress indicators, is the season when plants of the halophytic site show the highest nutritional quality for grazing cattle.

Dynamic Behavior of Systemic Insecticide Residues in Snapdragons

Pesticide application is used in horticulture to reduce plant damage from organisms such as insects and mites. Systemic insecticides are highly efficacious and readily taken up by plant tissues. However, pesticide-treated plants may impose risks to nontarget insects or other organisms within ecosystems. In this study, insecticide residues in nectar, leaves, and flower petals of the horticulturally significant herbaceous annual snapdragon, Antirrhinum majus (Lamiales: Plantaginaceae), were assessed at two locations over several weeks following foliar and drench treatment with five systemic insecticides. Concentrations of the insecticides were determined by liquid chromatography–mass spectrometry. The independent effects Application Method, Application Rate, and Time were statistically significant among all active ingredients in the three matrices in both sites in California (CA) and New Jersey (NJ). The interaction effects were also generally statistically significant in the CA site but less consistently so in the NJ site, dependent on the active ingredient and matrix. Post hoc analyses found the highest residue concentrations in leaves and the lowest in nectar, a trend generally consistent over time regardless of active ingredient for both the CA and NJ sites. The results of this study are discussed in the context of conserving pollinators and other beneficial insects. It is recommended that similar studies should be implemented in different geographical regions and climates, along with multiyear studies for perennial ornamental plants.

Effects of Photoperiod Treatments on Stock Plants and Cutting Rooting of Three Cultivars of Ornamental Perennials

Many species of herbaceous perennials now have numerous cultivars, with growth habits and flower colors unique to each cultivar. Vegetative propagation is required so that resulting plants are genetically identical to the parent plant. Although many cultivars are selected for precocious and vigorous flowering, it is often difficult to collect adequate vegetative cuttings from such cultivars for commercial production because juvenile (vegetative) growth is preferred for high-quality cuttings. Cuttings that are reproductive (with flower buds or flowers) can have reduced or delayed rooting and increased occurrences of fungal pathogens (especially Botrytis species), resulting in lack of crop uniformity. We sought to answer the question, can growing stock plants of herbaceous perennials under defined photoperiods extend the length of the vegetative period and enhance the rooting of cuttings harvested from these stock plants? In this study, stock plants of ‘P009S’ twinspur (Diascia integerrima), ‘Furman's Red’ sage (Salvia greggii), and ‘Wild Thing’ sage (Salvia greggii) were grown under ambient, 12-hour light, 10-hour light, and 8-hour light to determine if a particular photoperiod could be used to suppress reproductive growth by promoting vegetative growth, thereby enhancing cutting rooting success. Effects of photoperiod treatments varied among the plant cultivars studied. Plants grown under 8-hour photoperiod had longer duration of vegetative growth, smaller growth rates, and lower dry weights when compared with plants grown under 12-hour or 10-hour photoperiod. Plants grown under 12-hour photoperiod had shorter duration of vegetative growth, larger growth rates, and higher dry weights when compared with plants grown under 10-hour and 8-hour photoperiods. The probability of rooting of cuttings harvested from stock plants of ‘P009S’ twinspur, ‘Furman’s Red’ sage, and ‘Wild Thing’ sage grown under 12-hour and 10-hour photoperiods was greater when compared with cuttings harvested from stock plants grown under 8 h photoperiod.

Vegetation at the former open-pit Ningyo-toge mine, 36 years after closure treatment: Impact of soil cover on woody plant establishment and dominance of the perennial herb Miscanthus sinensis

Soil cover is a prevailing method used at mine sites to ensure the safety of hazardous materials and restore ecological functions when the base materials are unfavorable for plant growth. The former open-pit Ningyo-toge Mine was backfilled with overburden and neutralized smelting residues and covered with soil in 1987. After 36 years, the vegetation remained dominated by the perennial herb Miscanthus sinensis, and woody plant establishment did not progress successfully. This study investigated the factors that inhibited woody plant establishment at the site. The soil profile survey revealed that the soil cover formed Bg horizons (pseudogley soil) with cloudy mottling, representative of poorly drained soil. In the Bg horizon, woody plant roots of Pinus densiflora and Weigela hortensis exhibited growth inhibition. Elemental analysis revealed that in the Bg horizon the roots of P. densiflora and W. hortensis accumulated high Fe concentrations exceeding 10,000 mg/kg DW at critical levels. Our results suggested that woody plant roots in the Bg horizon may have suffered from chronic oxygen deficiency accompanied by excessive Fe stress in the soil cover. Topsoil water content (<50 mm) and microtopographic features were not critical factors disrupting woody plant establishment because some individuals were growing in areas with high soil water content, exceeding 60%. Considering that woody plant roots were developed primarily in the shallow A horizon, A horizon formation by M. sinensis is a key step in initiating woody plant establishment by improving the soil structure and physiochemical characteristics of the soil cover, such as carbon content, exchangeable nutrients, and air-filled porosity. For successful mine pollution control and vegetation recovery, implementing an appropriate topsoil system, such as native forest soil, loosely graded and minor infiltration layer above the overburden would be necessary.

Evaluation of Antioxidant and Anticancer Activities of Memecylon umbellatum in Breast Carcinoma and Lupeol and Beta-sitosterol Quantified by HPTLC

Introduction: Memecylon umbellatum is a perennial plant of the Melastomataceae family that grows in abundance in the Western Ghats and has been used traditionally to treat cancer and inflammatory conditions. Methods: From the literature survey, it was found that no substantial work has been carried out to identify the bioactive compounds by HPTLC method and to screen the antioxidant and anticancer activity of M. umbellatum. Hence, an effort has been made to carry out the phytochemical investigation by HPTLC method and to screen the antioxidant activity by ABTS assay, DPPH assay, Nitric oxide antioxidant assay, Iron chelating activity and Total antioxidant activity. Results: Total phenolics and flavonoids were carried out by using suitable methods. MCF-7 as well as MDA-MB-231 cells were used to test anticancer activities in vitro. Cell cycle analysis demonstrated that ethyl acetate extract caused G0/G1 phase arrest in MCF-7 cells. HPTLC analysis led to the identification of Lupeol from ethyl acetate extract. Conclusion: The anticancer activity of ethyl acetate extract of M. umbellatum was significant. The antioxidant and anticancer activity may attributed to Lupeol, Phenolic compounds and Flavonoids.

Ruscus Species Distributed in Türkiye

Ruscus species are represented by seven species in the world and four of these species (R. aculeatus L., R. hypoglossum L., R. hypophyllum L. and R. colchicus Yeo) grow naturally in the flora of Turkiye. Other Ruscus species (R. hyrcanus Woronow., R. x microglossus Bertol. and R. streptophyllus Yeo) are naturally distributed in different parts of the world. Ruscus species grow between 80 and 100 cm tall. These species have numerous evergreen leaf-like flattened structures, which have photosynthetic capability, on branched stems known as cladodes. The small violet flowers are situated on the center of cladodes. Their orange-red fruits are 5-10 mm in diameter. Ruscus species are perennial plants. In addition to their use as outdoor plants in landscape architecture, these species are mostly used as cut greens for flower arrangements and medicinal purposes, as well as for cosmetic products. Ruscus species are also known as geophytes due to the structure of their storage organs (rhizomes), which are located under the soil surface. In this compilation study, our main aims were to provide information about these species, which grow naturally in Türkiye’s flora and are uncontrollably collected from nature and put on the market, to reveal their potential for evaluation as ornamental plants and to increase awareness about these valuable native species to protect our genetic resources. The distribution regions in nature, various morphological properties and different usage areas of four Ruscus species naturally grown in Türkiye are given in detail.

Comparative chloroplast genomics and phylogenetic analysis of Oreomecon nudicaulis (Papaveraceae)

Oreomecon nudicaulis, commonly known as mountain poppy, is a significant perennial herb. In 2022, the species O. nudicaulis, which was previously classified under the genus Papaver, was reclassified within the genus Oreomecon. Nevertheless, the phylogenetic status and chloroplast genome within the genus Oreomecon have not yet been reported. This study elucidates the chloroplast genome sequence and structural features of O. nudicaulis and explores its evolutionary relationships within Papaveraceae. Using Illumina sequencing technology, the chloroplast genome of O. nudicaulis was sequenced, assembled, and annotated. The results indicate that the chloroplast genome of O. nudicaulis exhibits a typical circular quadripartite structure. The chloroplast genome is 153,903 bp in length, with a GC content of 38.87%, containing 84 protein-coding genes, 8 rRNA genes, 38 tRNA genes, and 2 pseudogenes. The genome encodes 25,815 codons, with leucine (Leu) being the most abundant codon, and the most frequently used codon is AUU. Additionally, 129 microsatellite markers were identified, with mononucleotide repeats being the most abundant (53.49%). Our phylogenetic analysis revealed that O. nudicaulis has a relatively close relationship with the genus Meconopsis within the Papaveraceae family. The phylogenetic analysis supported the taxonomic status of O. nudicaulis, as it did not form a clade with other Papaver species, consistent with the revised taxonomy of Papaveraceae. This is the first report of a phylogenomic study of the complete chloroplast genome in the genus Oreomecon, which is a significant genus worldwide. This analysis of the O. nudicaulis chloroplast genome provides a theoretical basis for research on genetic diversity, molecular marker development, and species identification, enriching genetic information and supporting the evolutionary relationships among Papaveraceae.

Prevalence and diversity of aphid vectored yellow dwarf viruses in Oregon perennial grass seed crops

Prevalence and diversity of aphid vectored yellow dwarf viruses in Oregon perennial grass seed crops

Effect of SlSAHH2 on metabolites in over-expressed and wild-type tomato fruit.

Tomato (Solanum lycopersicum) is an annual or perennial herb that occupies an important position in daily agricultural production. It is an essential food crop for humans and its ripening process is regulated by a number of genes. S-adenosyl-l-homocysteine hydrolase (AdoHcyase, EC 3.3.1.1) is widespread in organisms and plays an important role in regulating biological methylation reactions. Previous studies have revealed that transgenic tomato that over-express SlSAHH2 ripen earlier than the wild-type (WT). However, the differences in metabolites and the mechanisms driving how these differences affect the ripening cycle are unclear. To investigate the effects of SlSAHH2 on metabolites in over-expressed tomato and WT tomato. SlSAHH2 over-expressed tomato fruit (OE-5# and OE-6#) and WT tomato fruit at the breaker stage (Br) were selected for non-targeted metabolome analysis. A total of 733 metabolites were identified by mass spectrometry using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database and the Human Metabolome database (HMDB). The metabolites were divided into 12 categories based on the superclass results and a comparison with the HMDB. The differences between the two databases were analyzed by PLS-DA. Based on a variable important in projection value >1 and P < 0.05, 103 differential metabolites were found between tomato variety OE-5# and WT and 63 differential metabolites were found between OE-6# and WT. These included dehydrotomatine, L-serine, and gallic acid amongst others. Many metabolites are associated with fruit ripening and eight common metabolites were found between the OE-5# vs. WT and OE-6# vs. WT comparison groups. The low L-tryptophan expression in OE-5# and OE-6# is consistent with previous reports that its content decreases with fruit ripening. A KEGG pathway enrichment analysis of the significantly different metabolites revealed that in the OE-5# and WT groups, up-regulated metabolites were enriched in 23 metabolic pathways and down-regulated metabolites were enriched in 11 metabolic pathways. In the OE-6# and WT groups, up-regulated metabolites were enriched in 29 pathways and down-regulated metabolites were enriched in six metabolic pathways. In addition, the differential metabolite changes in the L-serine to flavonoid transformation metabolic pathway also provide evidence that there is a phenotypic explanation for the changes in transgenic tomato. The metabolomic mechanism controlling SlSAHH2 promotion of tomato fruit ripening has been further elucidated.

Podosphaera xanthii Causing Powdery Mildew on Salvia farinacea in Central China.

Salvia farinacea, commonly referred as mealycup sage, is a perennial herbaceous plant belonging to the Salvia genus of the Lamiaceae family. It originates from the Mediterranean region, North America, and Europe and is globally cultivated due to its appealing and captivating flowers. Moreover, mealycup sage is utilized as traditional Chinese medicinal plant for treatment of cardiovascular diseases (Li et al. 2018). In October 2023, powdery mildew-like symptoms were observed on Salvia farinacea plants cultivated in a garden located in Xinxiang City, Henan Province, China (113.93, 35.29). The leaves were covered with white and thin masses of mycelia, conidiophores and conidia of the fungus. About 100 plants were checked and 90 % were infected. There were a large number of white colonies with irregular or continuous round lesions on the adaxial and abaxial surfaces of the leaves, covering approximately 80% of the leaf area. The slightly or straight curved conidiophores (n = 30) were 46 to 145× 8 to 11 μm in size and consisted of foot cells, shorter cells and conidia. The ellipsoidal to oval conidia (n = 30), containing fibrosin bodies, were 24 to 35 × 12 to 19 μm in size and had a length/width ratio of 1.8 to 2.1. No chasmothecia were observed on leaves. These morphological features were consistent with those of Podosphaera xanthii (Braun and Cook 2012). Following the previously described method (White et al. 1990; Bradshaw et al. 2022; Zhu et al. 2022a), the sequences of ITS and Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) regions were amplified with specific primers ITS1/ITS4 (ITS1 5'-TCCGTAGGTGAACCTGCGG-3' ; ITS4 5'-TCCTCCGCTTATTGATATGC-3') and PMGAPDH1/PMGAPDH3R (PMGAPDH1 5'-GGAATGGCTATGCGTGTACC-3'; PMGAPDH3R 5'-CCCCATTCGTTGTCGTACCATG-3'), and the resulting sequences were uploaded in GenBank (Accession No. OR761885 and PP236082, respectively). BLASTn analysis showed that the sequence shared 560/565 (99%) and 272/272 (100%) homology with P. xanthii (MW301281) on Impatiens balsamina (Zhu et al. 2022b) and with P. xanthii (ON075658) on Cucumis melo (Bradshaw et al. 2022), respectively. The phylogenetic analysis clearly illustrated that the collected isolate of P. xanthii clustered in the same clade. The pathogenicity was tested according to the method previously described (Zhu et al. 2021). The fungus was inoculated onto the leaf surfaces of three healthy plants by blowing conidia from infected leaves with pressurized air. Non-inoculated plants were treated as control. Both the control and inoculated plants were separately placed in growth chambers under 60% humidity; light/dark, 16 h/8 h; and a temperature of 18°C. After a period of 12-15 days, the leaves of the inoculated plants exhibited signs of powdery mildew, whereas the control group remained unaffected. Therefore, the fungal pathogen was identified and confirmed as P. xanthii (isolate PXSF202310). Previously, P. xanthii was reported on Impatiens balsamina and S. farinacea from China and Korea (Zhu et al. 2021; Choi et al. 2022). As far as we know, this is the first documentation of P. xanthii on S. farinacea in central China. The presence of P. xanthii can lead to a deterioration in plant health and stunted growth, thereby negatively impacting both the decorative and medicinal value of S. farinacea. The recognition of P. xanthii on S. farinacea enhances our comprehension of this pathogen hosts and provides fundamental information for forthcoming disease control studies.

Assessment of sowing qualities of seeds and seasonal development of perennial herbal plants introduced at the Polar-Alpine Botanical Garden-Institute.

Assessment of sowing qualities of seeds and seasonal development of perennial herbal plants introduced at the Polar-Alpine Botanical Garden-Institute.

Smooth Brome (Bromus inermis L.)—A Versatile Grass: A Review

Smooth brome (Bromus inermis L.) is a species of perennial grass with growing economic importance. Initially, this species had attracted interest as a source of animal feed. Over the years, the interest in smooth brome increased significantly due to the growing knowledge about its advantages. The aim of this study was to explore the contemporary significance of smooth brome. This plant is characterized by a high tolerance to many negative environmental factors, such as periodic droughts, low temperatures and salinity, which contributes to its constant presence in the landscape of many countries. The moderate soil requirements of smooth brome, combined with the effective use of soil resources and rational nutrient utilization, contribute to high biomass yields that can reach 13 t/ha DM. The usefulness of this grass species in various management systems has been recognized in numerous research studies. Smooth brome can generate benefits in many branches of the economy. This efficient energy plant is used in paper production, and it is also recommended for the protection of fallow land or the reclamation of degraded land. Smooth brome prevents erosion, enhances biodiversity, and provides shelter for many animal species. This species fits well into the current assumptions of agricultural policy and increasingly demanding environmental standards. According to the latest guidelines, modern agriculture should pursue economic and environmental goals simultaneously. In this context, smooth brome constitutes a valuable link in sustainable development. Due to its numerous advantages, smooth brome not only provides high-quality feed and biomass but also effectively sequesters CO2, improves soil fertility and enhances biodiversity, which makes it an important element of agriculture and environmental protection.

Biological Flora of Britain and Ireland: Silene uniflora‡

Abstract This account presents information on all aspects of the biology of Silene uniflora Roth (S. maritima With., S. vulgaris Garcke subsp. maritima (With.) Á. &amp; D. Löve), Sea Campion, that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of Britain and Ireland: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history and conservation. Silene uniflora is a mat‐like perennial herb that in Britain and Ireland is primarily distributed in coastal habitats, notably on sea cliffs and shingle banks but also at the drift line and rarely on sand; it also has populations on mountains and heavy metal mine waste tips. All of these substrates tend to be oligotrophic, loose‐textured and freely draining, and often with adverse ion concentrations. It is found in suitable habitats around much of the Atlantic and Baltic coasts of Europe. Its breeding system is gynodioecious and gynomonoecious (some individuals bearing female flowers only, some bearing hermaphrodite flowers only and others with both types of flower). The proportions of the three types of individual vary considerably between populations, but hermaphrodite flowers tend to predominate. The showy, white, nectar‐producing flowers are produced continuously over the entire summer and are pollinated mainly by long‐tongued Hymenoptera and night‐flying moths but autogamous selfing is also frequent. Silene uniflora and its close relative S. vulgaris were the subject of a classic, decadal study involving genetical and transplant experiments that was seminal in the development of ‘experimental taxonomy’. More recently, attention has focused on the rapid evolution of Zn‐tolerant populations of S. uniflora growing on mine spoil and contaminated river gravels. It has also become a model organism for the study of sexually transmitted, castrating fungal diseases in plants (notably of the genus Microbotryum).

Investigating the effect of plant growth regulators in the endodormancy release in apricot by a metabolomic approach

AbstractEndodormancy is one of the most studied physiological processes in perennial plants like apricot. This period is vital both for the tree survival against the adverse climatic conditions of winter and for obtaining a proper flowering and fruit set. Many studies have remarked the importance of chill accumulation as the limiting factor for endodormancy release. The increase of mean temperatures caused by climate change has been seriously endangering this process during the last decades. Because of this, plant growth regulators for promoting endodormancy release have spread worldwide. However, due to the toxicity and the irregular efficiency, there is a great necessity of developing new environment-friendly regulators for promoting endodormancy release. In this 3-year study, we applied four different commercial plant growth regulators to the Flopría apricot cultivar. Two of them, Broston® and Erger® were the most effective ones to advance endodormancy release. The physiology and biochemistry behind these treatments were studied by a non-target metabolomic and expression analysis in flower buds. Metabolic groups, like phospholipids, only varied in treated samples, whereas others like by-products of L-Phe metabolism, or ABA significantly varied in both types of samples throughout endodormancy release. Finally, to validate these results, solutions of phospholipids, phenylpropanoids, or ABA, among others, were applied for the first time to apricot trees, showing, i.e., that phospholipids treated-trees released from endodormancy two weeks earlier than control. This study aims to be an initial stage for the elaboration of environmentally safe regulators in apricot, with a potential in other Prunus and temperate fruit tree species.

Melatonin Affects Leymus chinensis Aboveground Growth and Photosynthesis by Regulating Rhizome Growth

Leymus chinensis is a perennial rhizomatous clone plant. It exhibits strong rhizomatous tillering and clonal growth through asexual reproduction. The root system is interdependent with aboveground growth and root growth can regulate aboveground growth and photosynthesis. Melatonin has been shown to regulate root growth and promote photosynthesis. However, it remains unclear whether melatonin affects aboveground growth and photosynthesis by regulating rhizome growth. To address this gap, we studied nine Leymus chinensis from different geographical locations, all grown under the same conditions. We selected two materials with strong (LC19) and weak (LC2) rhizome growth abilities from nine materials and treated them with exogenous melatonin. We found there were significant positive correlations between stem length, plant height, leaf number and rhizome traits. Additionally, rhizome traits showed significant positive correlations with photosynthetic indices and chlorophyll content. Specifically, for LC2, treatment with 200 μmol/L melatonin significantly increased root length, the number of extravaginal ramets and rhizome clonal growth rate by 88.72%, 43.75% and 43.70%, respectively, resulting in significant increases in aboveground traits. Similarly, for LC19, 200 μmol/L melatonin treatment led to significant increases of 74.66%, 23.02%, 62.71% and 62.72% in four traits, respectively, along with aboveground trait improvements. Furthermore, around 300 μmol/L melatonin treatment promoted photosynthetic efficiency in LC2, while around 100 μmol/L melatonin treatment had the same effect in LC19. In conclusion, our study highlights the relationship between rhizome growth ability, aboveground growth and photosynthesis in Leymus chinensis. Additionally, it suggests that exogenous melatonin can enhance aboveground growth and photosynthesis by regulating rhizome growth.

Winter survival in red clover: experimental evidence for interactions among stresses

BackgroundThere is a lack of knowledge on the combined effects of different stresses on plants, in particular different stresses that occur during winter in temperate climates. Perennial herbaceous plants in temperate regions are exposed to many different stresses during winter, but except for the fact that cold temperatures induce resistance to a number of them, very little is known about their interaction effects. Knowledge about stress interactions is needed in order to predict effects of climate change on both agricultural production and natural ecosystems, and to develop adaptation strategies, e.g., through plant breeding. Here, we conducted a series of experiments under controlled conditions to study the interactions between cold (low positive temperature), clover rot infection (caused by Sclerotinia trifoliorum) and freezing, in red clover (Trifolium pratense) accessions. We also compared our results with winter survival in field experiments and studied associations between stress and shoot growth.ResultsExposure to low positive temperatures (cold acclimation) induced resistance to clover rot. There was a clear negative interaction effect between freezing stress and clover rot infection, resulting in up to 37% lower survival rate compared to what would have been expected from the additive effect of freezing and infection alone. Freezing tolerance could continue to improve during incubation under artificial snow cover at 3 °C in spite of darkness, and we observed compensatory shoot growth following freezing after prolonged incubation. At the accession level, resistance to clover rot was negatively correlated with growth in the field during the previous year at a Norwegian location. It was also negatively correlated with the shoot regrowth of control plants after incubation. Clover rot resistance tests under controlled conditions showed limited correlation with clover rot resistance observed in the field, suggesting that they may reveal variation in more specific resistance mechanisms.ConclusionsWe here demonstrate, for the first time, a strong negative interaction between freezing and infection with a winter pathogen. We also characterize the effects of cold acclimation and incubation in darkness at different temperatures on winter stress tolerance, and present data that support the notion that annual cycles of growth and stress resistance are associated at the genetic level.

The omission of seed banks in demography as an example of bias in ecology

Abstract Despite enthusiasm for big data in the life sciences, challenges arise because of biases and incomplete data. Demographic studies often overlook dormant life stages, which can skew inferences. They also tend to focus on few populations and short time spans. We assessed omissions of seed banks in demographic studies, exploring trends across life forms, climates, and taxonomic groups. We compared 172 species (192 cases) with independent seed bank and demographic studies. Approximately 25% of the demographic studies excluded known seed bank stages. The probability of omissions was lower for annuals and shrubs and higher for perennial herbs. We found no evidence that ecoregion or phylogeny explained these omissions. Modeling choices and study designs may explain patterns of seed bank omissions. Considering more populations reduced the chance of omissions. Omissions raise concerns for ecological analyses using databases. Leveraging large data is important, but we must be careful to understand their biases and limitations.

MIKC type MADS-box transcription factor LcSVP2 is involved in dormancy regulation of the terminal buds in evergreen perennial litchi (Litchi chinensis Sonn.).

SHORT VEGETATIVE PHASE (SVP), a member of the MADS-box transcription factor family, has been reported to regulate bud dormancy in deciduous perennial plants. Previously, three LcSVPs (LcSVP1, LcSVP2 and LcSVP3) were identified from litchi genome, and LcSVP2 was highly expressed in the terminal buds of litchi during growth cessation or dormancy stages and down-regulated during growth stages. In this study, the role of LcSVP2 in governing litchi bud dormancy was examined. LcSVP2 was highly expressed in the shoots, especially in the terminal buds at growth cessation stage, whereas low expression was showed in roots, female flowers and seeds. LcSVP2 was found to be located in the nucleus and have transcription inhibitory activity. Overexpression of LcSVP2 in Arabidopsis thaliana resulted in a later flowering phenotype compared to the wild-type control. Silencing LcSVP2 in growing litchi terminal buds delayed re-entry of dormancy, resulting in significantly lower dormancy rate. The treatment also significantly up-regulated litchi FLOWERING LOCUS T2 (LcFT2). Further study indicates that LcSVP2 interacts with an AP2-type transcription factor, SMALL ORGAN SIZE1 (LcSMOS1). Silencing LcSMOS1 promoted budbreak and delayed bud dormancy. Abscisic acid (200mg/L), which enforced bud dormancy, induced a short-term increase in the expression of LcSVP2 and LcSMOS1. Our study reveals that LcSVP2 may play a crucial role, likely together with LcSMOS1, in dormancy onset of the terminal bud and may also serve as a flowering repressor in evergreen perennial litchi.