Hortus Botanicus (Dec 2021)
Katsura trees (Cercidiphyllum Siebold et Zucc., Cercidiphyllaceae) in the Botanical Garden of Peter the Great: results of arboriculture, state and prospects of breeding
Abstract
Two species of Katsura trees - Cercidiphyllum japonicum and Cercidiphyllum magnificum – are presented in the collection of the Peter the Great Botanical Garden of the BIN after V. L. Komarova RAS in St. Petersburg since the early 1930s. It reaches a size of 13.5 m high in C. magnificum and up to 17.6 m in height in C. japonicum with a trunk diameter of up to 48 cm at the age of about 90 years. There is no freezing of plants in the conditions of the modern climate of the first decades of the XXI century. The Katsura trees are resistant to frost cracks. However, with age, it can be damaged by pathogenic fungi. Fungi pathogens Phellinus alni (Bondartsev) Parmasto and Armillaria lutea Gillet, as well as basidiomas of the facultative pathogen Fomitiporia punctata (P. Karst.) Murrill, have been identified. Both plants of Katsura trees are grown from local seeds, and Cercidiphyllum japonicum is self-seeding. Seed germination ranges from 9-11 %. The rooting rate of cuttings in different variants ranged from 16.7 to 79.2 %, with the best result when using a root formation stimulator in the form of a powder containing carbon single-walled nanotubes (79.2 %). Both species are promising for landscaping in St. Petersburg.
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