Assessment of the impact of horse-chestnut leaf miner (Cameraria ohridella Deschka & Dimič, 1986) on photosynthesis of common horse chestnut (Aesculus hippocastanum Linnaeus, 1753)

Abstract

The article presents the results of studies on Cameraria ohridella Deschka & Dimič, 1986 feeding on the state of the photosynthetic apparatus in Aesculus hippocastanum Linnaeus, 1753. The studies were carried out in June 2019 (during the life of C. ohridella first generation) on the territory of the Botanical Garden of the Oles Honchar Dnipro National University. Photosynthesis is one of the processes most susceptible to stress factors; important information on state of the photosynthetic apparatus in plants under influence of various abiotic and biotic factors can be obtained by fluorescence analysis. Chlorophyll fluorescence is an indicator that allow to investigate a behavior of photochemical reactions related to system II (PSII) in living objects as an indicator the most sensitive to effect of environmental factors. One of the effective methods for plant state monitoring is a technique on chlorophyll fluorescence induction (CFI) measurement, which at the present stage can be introduced due to the use of biosensors. The objective of our study was to establish characteristics of C. ohridella vital activity on the photosynthesis process in A. hippocastanum trees using CFI evaluation technique. To diagnose photosynthesis violation of native chlorophyll in a living leaf of A. hippocastanum, we used a portable fluorometer “Floratest” (spectral range for measuring fluorescence intensity 670 to 770 nm) developed by V. M. Glushkov Institute of Cybernetics of National Academy of Sciences of Ukraine. The studies were conducted using alive A. hippocastanum leaves not damaged by C. ohridella and, accordingly, the damaged ones. Analysis of the data obtained showed that the worm feeding affects all CFI parameters (initial CFI value (non-damaged leaf: 582 relative units, damaged: 264); “plateau” CFI value (1460 to 722); maximum CFI (1890 to 940) and stationary CFI value after light adaptation of the leaf (1530 to 746)). Our studies have shown that CFI technique using “Floratest” apparatus allow express determining the general condition of the plant by assessing the main process of vital activity, namely photosynthesis. Analysis of chlorophyll fluorescence parameters is a powerful and effective tool for determining the phytophage effect on the plant.