M. V. Maslova, E. V. Grosheva, M. L. Dubrovskii
Michurinsk State Agrarian University, ul. Internatsional’naya, 101, Michurinsk, Tambovskaya obl., 393760, Russian Federation
Abstract. The studies aimed to find spectroscopy methods for assessing the degree of tissue necrosis in red-leaved rootstock forms of apple trees under the influence of pathogenic microorganisms. The work was performed using sheet cuttings of five genotypes 3-4-7, 54-118, 62-396, 2-9-102, Paradizka Budagovsky (PB). The experiment was repeated five times. Spectral analysis of ethanol extracts of pigments was carried out after exposure to pathogenic fungi Cladosporium herbarum Link., Fusarium sporotriciella Bilai., Alternaria alternata (Fr.) Keissl., which were initially present on the leaves in all variants, and Pseudomonas syringae van Hall bacteria, which was artificially infected. To change the activity of the components of the “environment – host – parasite” system, some of the leaf cuts were irradiated with a laser. The final experimental design included options with the following order of influences: I – fungi; II – fungi, bacteria; III – fungi, laser; IV – fungi, bacteria, laser; V – fungi, laser, bacteria. The curves of the reflection spectra of leaf pigments with different degrees of necrosis were plotted on the basis of measurements with a CM-700d/600d spectrophotometer. The highest degree of chlorophyll degradation corresponded to the lower slope coefficients of the curves of the reflection spectra of pigments (k640-670 and k670-700) in the ranges of 640-670 nm and 670-700 nm, which were determined by the modulus of the IkI coefficient calculated using the linear trend equation. For weakly necrotic tissues (less than 1.0 points), these coefficients were higher than for leaves with a strong degree of necrotization (more than 4 points), by 30.6 and 16.2%, respectively. According to the indicators k640-670 and k670-700, the degree of chlorophyll degradation after exposure to pathogens was analysed in comparison with the control (samples with no necrosis – 6.77 and 11.74, respectively). The smallest differences from the control, and, consequently, the greatest resistance to the studied bacterial-fungal complex, were shown by the rootstock forms of PB (more than the control k640-670 by 3.5%, k670-700 by 0.2%) and 3-4-7 (less than control k640-670 by 4.3%, k670-700 by 2.2%).
Keywords: reflection spectra; plant pigments; pathogenic fungi; apple rootstocks.
Author Details: M. V. Maslova, Cand. Sc. (Agr.), senior research fellow (e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.); E. V. Grosheva, research fellow; M. L. Dubrovskii, Cand. Sc. (Agr.), head of the laboratory.
For citation: Maslova MV, Grosheva EV, Dubrovskii ML. [Changes in the spectral composition of reflected light in apple leaves under the influence of microorganisms]. Dostizheniya nauki i tekhniki APK. 2022;36(12):24-9. Russian. doi: 10.53859/02352451_2022_36_12_24.