RESUMO
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.
Assuntos
Raízes de Plantas , Filogenia , Temperatura , Caryophyllaceae , NitrogênioRESUMO
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.
Assuntos
Teorema de Bayes , Filogenia , Caryophyllaceae , Alternaria , MicélioRESUMO
BACKGROUND:During the percutaneous vertebroplasty, the optimal dose of bone cement that can bring favorable cement dispersion and remodel the biomechanical balance of the fractured vertebrae remains controversial. OBJECTIVE:To investigate the dispersion degree of small dose of bone cement in vertebroplasty. METHODS: In this experiment, 18 sheep selected with the same condition were randomly divided into three groups (group A, group B, group C), 6 in each group. A model of thoracolumbar vertebral compression fracture (T12, L1, L2) was made in each sheep. The injected volume of bone cement in groups A, B, C was 15％, 20％, 25％ of the average volume of adjacent vertebral bodies, respectively. Postoperative CT images were used to evaluate the bone cement dispersion. Dispersion degree of bone cement among the three groups was compared by the Kruskal-Wallis test. RESULTS AND CONCLUSION:There was no statistical difference in the dispersion degree of bone cement among the three groups, and the excellent and good rate of dispersion was over 80％. To conclude, the optimal dose of bone cement injected into the fractured vertebra is 15％ of the average volume of adjacent vertebral bodies, which can achieve good dispersion degree and restore the biomechanical stability of the vertebral body.