Green Synthesis of Silver Nanoparticles Using Drymaria cordata and Their Biocompatibility with Hemoglobin: A Therapeutic Potential Approach.

In this study, we present the synthesis and characterization of AgNPs using Drymaria cordata along with an assessment of their antioxidant, antibacterial, and antidiabetic activities. Antibacterial activities using four bacterial strains, free radical scavenging assays (DPPH and ABTS), and carbohydrate hydrolyzing enzyme inhibition assays were done to examine the therapeutic efficacy of AgNPs. Additionally, herein, we also evaluated the biocompatibility of the AgNPs using hemoglobin (Hb) as a model protein. A comprehensive analysis of Hb and AgNP interactions was carried out by using various spectroscopic, imaging, and size determination studies. Spectroscopic results showed that the secondary structure of Hb was not altered after its interaction with AgNPs. Furthermore, the thermal stability was also well maintained at different concentrations of nanoparticles. This study demonstrated a low-cost, quick, and eco-friendly method for developing AgNPs using D. cordata, and the biocompatible nature of AgNPs was also established. D. cordata-mediated AgNPs have potential applications against bacteria and diabetes and may be utilized for targeted drug delivery.

Chloroplast Genome Sequences and Phylogenetic Analysis of Eight Newly Sequenced Caryophyllaceae Species.

BACKGROUND: Caryophyllaceae is a big family composed of many economic and medicinal species. However, the phylogeny of the family is insufficient and genome data are lacking for many species. OBJECTIVE: Using next-generation sequencing (NGS) to acquire the chloroplast (cp) genomes of Eremogone acicularis (F.N.Williams) Ikonn., E. brevipetala (Tsui & L.H.Zhou) Sadeghian & Zarre, E. bryophylla (Fernald) Pusalkar & D.K.Singh, E. kansuensis (Maxim.) Dillenb. & Kadereit, Shivparvatia glanduligera (Edgew.) Pusalkar & D.K.Singh, Silene atsaensis (Marq.) Bocquet, S. caespitella Williams, and S. lhassana (Williams) Majumdar. METHODS: Bioinformatic software was used to conduct the comparative genome and phylogeny analysis of these cp genomes. RESULTS: The eight cp genomes were 132 188-151 919 bp in length, containing 130-132 genes. A/T was dominant in simple sequence repeats (SSRs). Forward repeats and palindromic repeats were the most frequent in long terminal repeats (LTRs). Compared with the four species of Eremogone Fenzl, the inverted repeat (IR) boundaries of S. caespitella, S. atsaensis, S. lhassana, and Sh. glanduligera were significantly expanded. Four and one mutational hotspots were identified in the large single copy (LSC) region and small single copy (SSC) region, respectively. The ratio of nonsynonymous substitution to synonymous substitution (Ka/Ks ratio) showed these cp genomes may have undergone strong purifying selection. In the phylogenetic trees, both Silene L. and Eremogone were monophyletic groups. However, Sh. glanduligera was closely related to Amaranthus hypochondriacus. CONCLUSION: These results have provided new evidence and useful information for species identification, evolution, and genetic research on the Caryophyllaceae. HIGHLIGHTS: In this study, eight newly sequenced cp genomes of Caryophyllaceae species were reported for the first time.

Complete chloroplast genomes of Cerastium alpinum, C. arcticum and C. nigrescens: genome structures, comparative and phylogenetic analysis.

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.

Evolution of the Sabulina verna group (Caryophyllaceae) in Europe: A deep split, followed by secondary contacts, multiple allopolyploidization and colonization of challenging substrates.

One of the major goals of contemporary evolutionary biology is to elucidate the relative roles of allopatric and ecological differentiation and polyploidy in speciation. In this study, we address the taxonomically intricate Sabulina verna group, which has a disjunct Arctic-alpine postglacial range in Europe and occupies a broad range of ecological niches, including substrates toxic to plants. Using genome-wide ddRAD sequencing combined with morphometric analyses based on extensive sampling of 111 natural populations, we aimed to disentangle internal evolutionary relationships and examine their correspondence with the pronounced edaphic and ploidy diversity within the group. We identified two spatially distinct groups of diploids: a widespread Arctic-alpine group and a spatially restricted yet diverse Balkan group. Most tetraploids exhibited a considerably admixed ancestry derived from both these groups, suggesting their allopolyploid origin. Four genetic clusters in congruence with geography and mostly supported by morphological traits were recognized in the diploid Arctic-alpine group. Tetraploids are split into two distinct and geographically vicariant groups, indicating their repeated polytopic origin. Furthermore, our results also revealed at least five-fold parallel colonization of toxic substrates (serpentine and metalliferous), altogether demonstrating a complex interaction between geography, challenging substrates and polyploidy in the evolution of the group. Finally, we propose a new taxonomic treatment of this complex.

Palynomorphological Observations on the Genus Sabulina Rchb. (Caryophyllaceae) from Turkey Using Light Microscopy and Scanning Electron Microscopy.

Pollen morphology of 28 taxa belonging to the genus Sabulina Rchb. (Caryophyllaceae) from Turkey was examined and compared using light microscopy and scanning electron microscopy. The current study aimed to describe the palynological characteristics of the Sabulina taxa and to assess the diagnostic value of these features for taxonomic implications. The pollen grains of Sabulina are radially symmetrical, apolar, rarely isopolar, and pantopolyporate with 8-28 pores. Their shape is prolate-spheroidal with the A axes (long axes) 19.5 µm and the B axes (short axes) 19-39.5 µm. Exine sculpturing is microechinate-punctate in all taxa. Principal component analysis was used to evaluate the significant pollen morphological characters for distinguishing the taxa, with three components accounting for 95.112% of the total variance. Numerical analysis revealed that pollen sizes, pore diameters, pore numbers, distance between pores, spinule density, and punctum numbers are particularly the most useful variables for separating the Sabulina taxa. The results also display a partial relationship between the Sabulina taxa clusters based on pollen morphology and the systematics of these taxa based on general macromorphology.

Chitosan Enhances Low-Dosage Difenoconazole to Efficiently Control Leaf Spot Disease in Pseudostellaria heterophylla (Miq.) Pax.

Pseudostellaria heterophylla (Miq.) Pax is a popular clinical herb and nutritious health food. However, leaf spot disease caused by fungal pathogens frequently occurs and seriously influences the growth, quality, and yield of P. heterophylla. In this work, the field control roles of difenoconazole, chitosan, and their combination in the leaf spot disease in P. heterophylla and their effects on the disease resistance, photosynthetic capacity, medicinal quality, and root yield of P. heterophylla are investigated. The results manifest that 37% difenoconazole water-dispersible granule (WDG) with 5000-time + chitosan 500-time dilution liquid had a superior control capacity on leaf spot disease with the control effects of 91.17%~88.19% at 15~30 days after the last spraying, which significantly (p < 0.05) exceeded that of 37% difenoconazole WDG 3000-time dilution liquid and was significantly (p < 0.01) higher than that of 37% difenoconazole WDG 5000-time dilution liquid, chitosan 500-time dilution liquid, or chitosan 1000-time dilution liquid. Simultaneously, this combination could more effectively enhance the disease resistance, photosynthetic capacity, medicinal quality, and tuberous root yield of P. heterophylla compared to when these elements were applied alone, as well as effectively reduce difenoconazole application. This study emphasizes that chitosan combined with a low dosage of difenoconazole can be proposed as a green, efficient, and alternative formula for controlling leaf spot disease in P. heterophylla and enhancing its resistance, photosynthesis, quality, and yield.

[Identification and biological characterization of pathogen causing black spot of Pseudostellaria heterophylla in Fujian province].

In Zherong county, Fujian province, the black spot of Pseudostellaria heterophylla often breaks out in the rainy season from April to June every year. As one of the main leaf diseases of P. heterophylla, black spot seriously affects the yield and quality of the medicinal material. To identify and characterize the pathogens causing black spot, we isolated the pathogens, identified them as a species of Alternaria according to Koch's postulates, and then tested their pathogenicity and biological characteristics. The results showed that the pathogens causing P. heterophylla black spot were A. gaisen, as evidenced by the similar colony morphology, spore characteristics, sporulation phenotype, and the same clade with A. gaisen on the phylogenetic tree(the maximum likelihood support rate of 100% and the Bayesian posterior probability of 1.00) built based on the tandem sequences of ITS, tef1, gapdh, endoPG, Alta1, OPA10-2, and KOG1077. The optimum conditions for mycelial growth of the pathogen were 25 ℃, pH 5-8, and 24 h dark culture. The lethal conditions for mycelia and spores were both treatment at 50 ℃ for 10 min. We reported for the first time the A. gaisen-caused black spot of P. heterophylla. The results could provide a theoretical basis for the diagnosis and control of P. heterophylla leaf spot diseases.

[Cloning and functional verification of PhAEP gene, a key enzyme for biosynthesis of heterophyllin A in Pseudostellaria heterophylla].

This paper aimed to study the role of asparagine endopeptidase(AEP) gene in the biosynthesis mechanism of cyclic peptide compounds in Pseudostellaria heterophylla. The transcriptome database of P. heterophylla was systematically mined and screened, and an AEP gene, tentatively named PhAEP, was successfully cloned. The heterologous function verification by Nicotiana benthamiana showed that the expression of the gene played a role in the biosynthesis of heterophyllin A in P. heterophylla. Bioinformatics analysis showed that the cDNA of PhAEP was 1 488 bp in length, encoding 495 amino acids with a molecular weight of 54.72 kDa. The phylogenetic tree showed that the amino acid sequence encoded by PhAEP was highly similar to that of Butelase-1 in Clitoria ternatea, reaching 80%. The sequence homology and cyclase active site analysis revealed that the PhAEP enzyme may specifically hydrolyse the C-terminal Asn/Asp(Asx) site of the core peptide in the HA linear precursor peptide of P. heterophylla, thereby participating in the ring formation of the linear precursor peptide. The results of real-time quantitative polymerase chain reaction(RT-qPCR) showed that the expression level of PhAEP was the highest in fruits, followed by in roots, and the lowest in leaves. The heterophyllin A of P. heterophylla was detected in N. benthamiana that co-expressed PrePhHA and PhAEP genes instantaneously. In this study, the PhAEP gene, a key enzyme in the biosynthesis of heterophyllin A in P. heterophylla, has been successfully cloned, which lays a foundation for further analysis of the molecular mechanism of PhAEP enzyme in the biosynthesis of heterophyllin A in P. heterophylla and has important significance for the study of synthetic biology of cyclic peptide compounds in P. heterophylla.

Parallel adaptation to lower altitudes is associated with enhanced plasticity in Heliosperma pusillum (Caryophyllaceae).

High levels of phenotypic plasticity are thought to be inherently costly in stable or extreme environments, but enhanced plasticity may evolve as a response to new environments and foster novel phenotypes. Heliosperma pusillum forms glabrous alpine and pubescent montane ecotypes that diverged recurrently and polytopically (parallel evolution) and can serve as evolutionary replicates. The specific alpine and montane localities are characterized by distinct temperature conditions, available moisture, and light. Noteworthy, the ecotypes show a home-site fitness advantage in reciprocal transplantations. To disentangle the relative contribution of constitutive versus plastic gene expression to altitudinal divergence, we analyze the transcriptomic profiles of two parallely evolved ecotype pairs, grown in reciprocal transplantations at native altitudinal sites. In this incipient stage of divergence, only a minor proportion of genes appear constitutively differentially expressed between the ecotypes in both pairs, regardless of the growing environment. Both derived, montane populations bear comparatively higher plasticity of gene expression than the alpine populations. Genes that change expression plastically or constitutively underlie similar ecologically relevant pathways, related to response to drought and trichome formation. Other relevant processes, such as photosynthesis, rely mainly on plastic changes. The enhanced plasticity consistently observed in the montane ecotype likely evolved as a response to the newly colonized, drier, and warmer niche. We report a striking parallelism of directional changes in gene expression plasticity. Thus, plasticity appears to be a key mechanism shaping the initial stages of phenotypic evolution, likely fostering adaptation to novel environments.

[Common diseases and drug use of Pseudostellaria heterophylla].

Pseudostellaria heterophylla in large-scale cultivation needs to apply pesticides to control diseases, and non-standard use of pesticide may cause excessive pesticide residues in medicinal materials, increasing the risk of clinical medication. To accurately monitor the residual pesticides, this paper investigated the drug use during the process of P. heterophylla disease prevention in 25 P. he-terophylla planting enterprises or individual households in Guizhou province. It was found that there were 8 common diseases in P. he-terophylla planting, including leaf spot, downy mildew, virus disease, root rot, dropping disease, purple feather disease, white silk disease, and damping-off disease. Twenty-three kinds of pesticides were used in disease control, mainly chemical synthetic pesticides, accounting for 78.3%, followed by biological pesticides and mineral pesticides, accounting for 13.0% and 8.7%, respectively. The disease prevention and control drugs were all low-toxic pesticides, and there were no varieties banned in the Chinese Pharmacopoeia(2020 edition). However, the pesticides used have not been registered on P. heterophylla, and the excessive use of drugs was serious. The present monitoring of pesticide residues in P. heterophylla is mainly based on traditional pesticides such as organochlorine, organophosphorus, and carbamate, which does not effectively cover the production of drugs and had certain safety risks. It is suggested to speed up the research and registration of drug use in the production of P. heterophylla, increase the use of biological pesticides, and further improve the monitoring indicators of pesticide residues in combination with the actual production of drugs, so as to promote the high-quality development of P. heterophylla industry.

[Identification and biological characteristics of violet root rot pathogen of Pseudostellaria heterophylla in Fujian province].

Violet root rot is one of the main root diseases in the production process of Pseudostellaria heterophylla. To clarify the pathogenic species that cause the violet root rot of P. heterophylla in Fujian province, the roots and the sclerotia with violet root rot symptoms were collected from the main producing areas of P. heterophylla(Fujian province) from 2017 to 2021, and the pathogens were isolated by tissue separation method and identified by morphology and multi-gene phylogenetic analysis. Additionally, the biological characteristics of the pathogens were studied and the fungicides were determined. The results showed that 78 strains of violet root rot were isolated from the collected root samples, which belonged to one type after preliminary morphological identification. Two represen-tative strains were selected from the pathogens for multi-gene phylogenetic analysis, and they were clustered with Helicobasidium mompa together. The suitable culture conditions for the mycelium were OA medium, 25 ℃, pH 6, and ammonium oxalate as the nitrogen source. The lethal temperature of the mycelium was 50 ℃ for 10 minutes. Moreover, 99.1% propiconazole and 98.7% azoxystrobin had the optimal bacteriostatic effect, and the concentrations with the 50% bacteriostatic rate were 16.85 and 12.24 µg·mL~(-1), respectively. On the basis of the above results, the pathogen causing violet root rot of P. heterophylla in Fujian province was H. mompa. The medium type, growth temperature, pH value, nitrogen source, etc. had significant effect on the growth of mycelium.

Polar localization of new flavonoids from aerial parts of Scleranthus perennis and Hottonia palustris and their modulatory action on lipid membranes properties.

The aim of this study was to characterize, for the first time, the interactions, location, and influence of flavonoids isolated from aerial parts of Scleranthus perennis (Caryophyllaceae) and Hottonia palustris (Primulaceae) on the properties of model lipid membranes prepared from dipalmitoylphosphatidylcholine (DPPC) and egg yolk phosphatidylcholine (EYPC). The tested compounds incorporated into liposomes into the region of the polar heads or at the water/membrane interface of DPPC phospholipids. Spectral effects accompanying the presence of polyphenols revealed their effect on ester carbonyl groups apart from SP8. All polyphenols brought about reorganization of the polar zone of liposomes as it was observed by FTIR technique. Additionally, fluidization effect was noted in the region of symmetric and antisymmetric stretching vibrations of the CH2 and CH3 groups with exception to HZ2 and HZ3. Similarly, in EYPC liposomes, they interacted mainly with the regions of the choline heads of the lipids and had various effects on the carbonyl ester groups with exception to SP8. The region of polar head groups is restructured due to the presence of the additives in liposomes. The outcomes obtained using the NMR technique confirmed the locations of all of the tested compounds in the polar zone and indicated a flavonoid-dependent modifying effect towards lipid membranes. HZ1 and SP8 raised motional freedom in this region whereas opposite effect was revealed for HZ2 and HZ3. In the hydrophobic region restricted mobility was noted. In this report we discuss the mechanism of previously undescribed flavonoids in terms of their actions on membranes.

Polygenic routes lead to parallel altitudinal adaptation in Heliosperma pusillum (Caryophyllaceae).

Understanding how organisms adapt to the environment is a major goal of modern biology. Parallel evolution-the independent evolution of similar phenotypes in different populations-provides a powerful framework to investigate the evolutionary potential of populations, the constraints of evolution, its repeatability and therefore its predictability. Here, we quantified the degree of gene expression and functional parallelism across replicated ecotype formation in Heliosperma pusillum (Caryophyllaceae), and gained insights into the architecture of adaptive traits. Population structure analyses and demographic modelling support a previously formulated hypothesis of parallel polytopic divergence of montane and alpine ecotypes. We detect a large proportion of differentially expressed genes (DEGs) underlying divergence within each replicate ecotype pair, with a strikingly low number of shared DEGs across pairs. Functional enrichment of DEGs reveals that the traits affected by significant expression divergence are largely consistent across ecotype pairs, in strong contrast to the nonshared genetic basis. The remarkable redundancy of differential gene expression indicates a polygenic architecture for the diverged adaptive traits. We conclude that polygenic traits appear key to opening multiple routes for adaptation, widening the adaptive potential of organisms.

Developmental Toxicity Assessment of Drymaria Cordata (Linn.) Willd using Zebrafish Embryo.

INTRODUCTION: Drymaria cordata (Linn.) Willd is a creeping herb belonging to the Caryophyllaceae family, widely used as a traditional medicine in Africa and North-east India for various ailments. Many therapeutic applications of D. cordata have been reported in various scientific studies, but the teratogenicity study of this herb has not been documented till now. METHODS: The present study aimed to assess the developmental toxic effect and median lethal concentration (LC50) of methanol extract of Drymaria cordata leaf (DCME) using zebrafish embryos. After spawning of male and female zebrafish, healthy zebrafish embryos were selected by microscopic screening and transferred into 96-well plate for the study. Embryos were exposed to DCME at concentrations ranging from 50-400 µg/ml in 2% DMSO from 24 hpf to 72 hpf. RESULTS: Developmental and morphological abnormalities were microscopically evaluated. Fifty percent lethal concentration (LC50) of DCME was determined by observation from 24 hpf to 72 hpf. The concentration-dependent toxic effects of DCME on developing embryos of zebrafish were found in the study in a time-dependent manner. CONCLUSION: At 72 hpf, the median lethal concentration (LC50) of DCME was found with visible developmental defects, such as heartbeat rate, less pigmentation, oedema, spinal curvature, immature yolk sac as well as reduced hatching rate and a slow growth. The median lethal dose was found to be 448 µg/ml at 72 hpf for zebra fish embryos, meriting further studies on toxicological profiling of the plants.

Contrasting effects of two phenotypes of an alpine cushion plant on understory species drive community assembly.

In alpine systems, cushion plants act as foundation species by ameliorating local environmental conditions. Empirical studies indicate that contrasting phenotypes of alpine cushion species have different effects on understory plant species, either facilitative or competitive. Furthermore, dependent species within each community type might also exhibit different responses to each cushion phenotype, which can be clustered into several "response groups". Additionally, these species-groups specific responses to alpine cushion species phenotypes could alter community assembly. However, very few studies have assessed responses of dependent communities at species-group levels, in particular for both above- and below-ground communities. Here, we selected a loose and a tight phenotype of the alpine cushion species Thylacospermum caespitosum in two sites of northwest China, and use the relative intensity of interactions index to quantify cushion plant effects on subordinate communities of plants and soil fungi and bacteria. We assessed variations in responses of both above- and below-ground organisms to cushion plant effects at species-group level. Species-group level analyses showed that the effects of the phenotype varied among groups of each of the three community types, and different species-groups were composed by unique taxa. Additionally, we found that loose cushions enhanced stochastic processes in community assembly, for plants and soil fungi but not for soil bacteria. These variations of phenotypic effects on different species-group induced contrasting taxonomic composition between groups, and alter community assembly thereby. Our study highlights the occurrence of contrasting effects of two phenotypes of a foundation cushion plant on understory plants, soil fungi and bacteria community composition, but not necessarily on their richness. We also showed that assessing responses of understory species at the species-group level allows a more realistic and mechanistic understanding of biotic interactions both for above- and below-ground communities.

Genetic variation of Cerastium alpinum L. from Babia Góra, a critically endangered species in Poland.

Babia Góra massif is the only site of occurrence of the Cerastium alpinum L. in Poland, an arctic-alpine perennial plant with a wide distribution in North America, northwestern Asia, and Europe. To determine whether the isolated Polish populations are genetically distinct, we have performed an evaluation of C. alpinum from Babia Góra with the use of iPBS markers. A total number of 133 individuals of C. alpinum from seven populations representing four localizations of the species were analyzed, i.e., from Babia Góra (Poland), Alps (Switzerland), Nuolja massif (Sweden), and Kaffiøyra (Svalbard, Norway). Genetic analysis of all C. alpinum samples using eight PBS primers identified 262 bands, 79.4% of which were polymorphic. iPBS markers revealed low genetic diversity (average He = 0.085) and high population differentiation (FST = 0.617). AMOVA results confirmed that the majority of the genetic variation (62%) was recorded among populations. The grouping revealed by PCoA showed that C. alpinum from Svalbard is the most diverged population, C. alpinum from Switzerland and Sweden form a pair of similar populations, whereas C. alpinum from the Babia Góra form a heterogeneous group of four populations. Results of isolation by distance analysis suggested that the spatial distance is the most probable cause of the observed differentiation among populations. Although significant traces of a bottleneck effect were noted for all populations of C. alpinum from Babia Góra, the populations still maintain a low but significant level of genetic polymorphism. These results are of great importance for developing conservation strategies for this species in Poland.

Extraction of Polysaccharides from Root of Pseudostellaria heterophylla (Miq.) Pax. and the Effects of Ultrasound Treatment on Its Properties and Antioxidant and Immune Activities.

The hydrophilic polysaccharides (PS) were isolated and purified from the tuberous roots of Pseudostellaria heterophylla. The extraction process of PS from Pesudostellariae radix was optimized by single-factor experiments and orthogonal design. The extract was purified by DEAE cellulose column to obtain the pure polysaccharide PHP. Then PHP was treated with different intensities of sonication to study the effect of sonication on PHP's characteristics and its biological activity in vitro and in vivo. The results of this study revealed that ultrasound treatment did not significantly change the properties of PHP. Further, with the increase of ultrasound intensity, PHP enhanced the proliferation and phagocytosis of macrophage RAW264.7. Meanwhile, it could also significantly improve the body's antioxidant activity and immune function. The results of this study demonstrated that PHP has the potential as a food additive with enhanced antioxidant and immune functions, and its biological activities could be enhanced by sonication.

Identification and biological characteristics of violet root rot pathogen of Pseudostellaria heterophylla in Fujian province / 中国中药杂志

Violet root rot is one of the main root diseases in the production process of Pseudostellaria heterophylla. To clarify the pathogenic species that cause the violet root rot of P. heterophylla in Fujian province, the roots and the sclerotia with violet root rot symptoms were collected from the main producing areas of P. heterophylla(Fujian province) from 2017 to 2021, and the pathogens were isolated by tissue separation method and identified by morphology and multi-gene phylogenetic analysis. Additionally, the biological characteristics of the pathogens were studied and the fungicides were determined. The results showed that 78 strains of violet root rot were isolated from the collected root samples, which belonged to one type after preliminary morphological identification. Two represen-tative strains were selected from the pathogens for multi-gene phylogenetic analysis, and they were clustered with Helicobasidium mompa together. The suitable culture conditions for the mycelium were OA medium, 25 ℃, pH 6, and ammonium oxalate as the nitrogen source. The lethal temperature of the mycelium was 50 ℃ for 10 minutes. Moreover, 99.1% propiconazole and 98.7% azoxystrobin had the optimal bacteriostatic effect, and the concentrations with the 50% bacteriostatic rate were 16.85 and 12.24 μg·mL~(-1), respectively. On the basis of the above results, the pathogen causing violet root rot of P. heterophylla in Fujian province was H. mompa. The medium type, growth temperature, pH value, nitrogen source, etc. had significant effect on the growth of mycelium.

Common diseases and drug use of Pseudostellaria heterophylla / 中国中药杂志

Pseudostellaria heterophylla in large-scale cultivation needs to apply pesticides to control diseases, and non-standard use of pesticide may cause excessive pesticide residues in medicinal materials, increasing the risk of clinical medication. To accurately monitor the residual pesticides, this paper investigated the drug use during the process of P. heterophylla disease prevention in 25 P. he-terophylla planting enterprises or individual households in Guizhou province. It was found that there were 8 common diseases in P. he-terophylla planting, including leaf spot, downy mildew, virus disease, root rot, dropping disease, purple feather disease, white silk disease, and damping-off disease. Twenty-three kinds of pesticides were used in disease control, mainly chemical synthetic pesticides, accounting for 78.3%, followed by biological pesticides and mineral pesticides, accounting for 13.0% and 8.7%, respectively. The disease prevention and control drugs were all low-toxic pesticides, and there were no varieties banned in the Chinese Pharmacopoeia(2020 edition). However, the pesticides used have not been registered on P. heterophylla, and the excessive use of drugs was serious. The present monitoring of pesticide residues in P. heterophylla is mainly based on traditional pesticides such as organochlorine, organophosphorus, and carbamate, which does not effectively cover the production of drugs and had certain safety risks. It is suggested to speed up the research and registration of drug use in the production of P. heterophylla, increase the use of biological pesticides, and further improve the monitoring indicators of pesticide residues in combination with the actual production of drugs, so as to promote the high-quality development of P. heterophylla industry.