In an attempt to find biological fungicides, we screened 18 medicinal plants used in Chinese traditional medicine for their activity against Embellisia astragali, the causative fungus of yellow dwarf and root-rot disease in standing milkvetch (Astragalus adsurgens Pall.). The antifungal efficacy of ethanolic extracts of these plants was tested in vitro. Our results show that among the 18 plants tested, the ethanolic extracts of Saposhnikovia divaricata, Allium sativum and Juglans regia totally inhibited mycelial growth of E. astragali. These three extracts also significantly inhibited spore germination of E. astragali, with inhibition rates ranging from 86% to 88%. In addition, the same extract from the same plant part indicated the strongest antifungal activity against E. astragali, with a minimal inhibitory concentration value of 50 mg mL–1. These results demonstrate that plant-derived products have a high potential to control yellow dwarf and root-rot disease in standing milkvetch.
Integrating new synthetic methods and experimental techniques
from
the latest research reports into undergraduate laboratory experiments
is of great significance, as it enables students to learn the cutting-edge
technology of organic chemistry and cultivates their experimental
skills and innovative thinking. In this study, an experiment on the
iron salt-catalyzed synthesis of chromone [2,3-b]
indole derivatives, based on the latest report, was developed to train
senior undergraduate students’ experimental skills and increase
their basic knowledge in organic synthesis, especially those majoring
in Organic Chemistry, Applied Chemistry, and Pharmaceutical Chemistry,
among others. Incorporating this experiment into laboratory activities
can strengthen students’ fundamental knowledge of organic chemistry,
including Grignard reaction, substitution, addition, carbocation,
tautomerism, intramolecular cyclization, and elimination, and enhance
their skills in modern organic synthesis techniques, such as Schlenk
technology for anhydrous and anaerobic operation, thin-layer chromatography
for monitoring reaction progress, and column chromatography for the
separation and purification of products. Additionally, this approach
can help cultivate students’ scientific thinking and creativity
and stimulate their enthusiasm for scientific research. The feasibility
of introducing this latest scientific achievement into undergraduate
laboratory experiments was verified by randomly selecting 12 undergraduates
majoring in Applied Chemistry as pretest samples. The assessment results
showed that the product yield obtained by different groups of students
ranged from 72.6% to 85.8%, indicating a relatively high level of
achievement, and the average score of the post-test was 81, which
is a satisfactory outcome for such a comprehensive experiment.
A new leaf spot disease was observed on leaves of Rheum palmatum (Chinese rhubarb) in Northwest China (Gansu Province) starting in 2005. A Septoria-like fungus was isolated and completion of Koch's postulates confirmed that the fungus was the casual agent of the leaf spot disease. Morphology and molecular methods were combined to identify the pathogen. The fungus produced conidiomata pycnidia and the conidia were 2~5 septate, 61.2~134.1 µm in length and 3.53~5.3 µm in width, which is much larger than the known Spetoria species that infects Polygonaceae species. Phylogenic analysis of the internal transcribed spacer region confirmed that this Spetoria-like fungus is within the Spetoria genus but distinct from known Spetoria species. Together, these morphological and phylogenetic data support that the R. palmatum infecting Spetoria strain is a newly-described plant pathogenic species.
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