Diagnostics of mildew related clematis damage with scanning electronic and confocal laser microscopy

The article is devoted to the investigation of the powdery mildew pathogens in the collection of Clematis L. in the Department of Ornamental Plants of the Main Botanical Garden named after N.V. Tsitsin RAS. In the first part of the article, the authors present general information about these ornamental plants. The taxonomy of mildew fungi parasitizing on the genus Clematis L. is discussed. A historical reference and modern assessment of the pathogen species belonging are given and the danger of the development of this disease in the collections is presented. In the next part of the work, the botanical composition of the studied collection is presented, and the methods and techniques is described, especially scanning electron and confocal laser microscopy, as well as morphometric analysis. In the section devoted to the results of the study, an assessment is made of the degree of damage to the plants of the clematis collection and a detailed morphometric characterization of the identified mildew pathogen, based on the microphotographs obtained by the cryoSEM and KLSM methods. After analyzing the morphometric data, the authors summarize their work and conclude that a collection of the genus Clematis L. has been infested with Erysiphe aquilegiae var. ranunculi (Grev.) R.Y. Zheng & G.Q. Chen. It is concluded, that plant damage as a wholew a not high, because the pathogen was found only in 13 from 60 examined Clematis species visually and by the cryo-SEM method. Severe and medium damage by the mildew fungus E. aquilegiae var. ranunculi was registered in 4 representatives of the collection. A minor damage was registered in 9 varieties of the collection.