CHLOROPHYL FLUORESCENCE IN LEAVES OF PLANTS OF THE GENUS ACER L. UNDER THE INFLUENCE OF SAWADAEA BICORNIS (WALLR.) MIYABE

Abstract

The article presents the results of a study on the impact of Sawadaea bicornis (Wallr.) Miyabe on the photosynthetic apparatus of four species of the Acer L. genus using the chlorophyll fluorescence induction (ChlF) method, which can currently be implemented with biosensors. Maples are widely used for the formation of park and forest park phytocenoses, in group and individual plantings, as well as for landscaping urban squares, avenues, and boulevards. However, in urban environments, maples are more vulnerable to pathogens. Infection by phytopathogenic fungi reduces their ornamental value and disrupts photosynthetic and transpiration processes, leading to the drying out and death of individual branches or entire trees. Powdery mildew, a disease caused by the parasitic fungus Sawadaea bicornis (Wallroth) Miyabe 1937, is one of the most common diseases affecting both young saplings and mature maple trees. To diagnose photosynthesis disturbances of native chlorophyll in the living leaves of various Acer species, the portable fluorometer “FLS 10s” was used. Measurements were conducted on living leaves of Norway maple (A. platanoides L.), Tatar maple (A. tataricum L.), sycamore maple (A. pseudoplatanus L.), and boxelder maple (A. negundo L.) in September 2024. Measurements were taken on both completely unaffected and powdery mildew-affected leaves from the same tree (seven leaves per condition). The percentage of leaf blade infection by the phytopathogen was determined visually. A high informativeness of the induction changes in chlorophyll fluorescence in the structural organization of Norway maple chloroplasts was revealed, as determined by parameters such as Fo, Fm, Fv, Fv/Fо, Fv/Fm, (Fm–Fst)/Fst, (Fp–Fо)/Fv. Our research demonstrated that the CFI method, using the “FLS 10s” device, enables rapid assessment of the overall condition of a plant by evaluating its primary life-sustaining process –тphotosynthesis. The analysis of chlorophyll fluorescence parameters serves as a powerful and effective tool for determining the impact of the parasitic fungus on the host plant.