According to the literature [2, 3], C 6 and C 7 aliphatic alcohols and aldehydes and geraniol, linalool, caryophyllene, and terpineol have been isolated and identified from aqueous extracts of leaves of the potato Solanum tuberosum L. At the same time, it is known that the composition and structure of extractive substances differ substantially from the hydrocarbon components constituting the native scent of living plants [4].We have previously reported the identification of trans-caryophyllene as the main component of the native scent of potato leaves and of the volatiles emitted by the Colorado beetle Leptinotarsa decemlineata Say [ 1, 5]. The aim of the present work was to establish the composition and structure of the native scent of potato plants, which will lead to a deeper understanding of the mechanisms of chemocommunication in the biological pair of potato--Colorado beetle and also to the creation of effective methods of combating this pest.To identify the volatile substances emitted into the atmosphere by potato leaves we used a procedure [6--11] based on the dynamic gas extraction of these compounds with the aid of an effective adsorbent under the conditions of the natural growth of the plank followed by the desorption and analysis of the terpenes obtained with the aid of capillary gas chromatography and mass spectrometry, and also by comparing the hydrocarbons obtained with authentically known specimens.A chromatogram of the mixture of substances constituting the native scent of a potato of the variety Adretta, which is shown in Fig. 1, contains more than a score of peaks in the region characteristic for the retention times of sesquiterpenes (T = 12--20 min). We analyzed peaks 1--21 the intensities of which in the mixture exceeded a level of 1%. For the majority of the peaks (excluding 15, 16, and 19) the mass spectrum (MS) contained the molecular ion (ndz 204) witnessing that they belonged to the sesquiterpene series (empirical formula C15H24). Each of the chromatographic peaks was identified from its retention index (/), which was calculated as described in the literature [6, 9] and was compared with the published values, lli~ for the sesquiterpene series [9]. Their agreement (within the limits of standard deviations) was a necessary condition for the identification of the compounds. A second criterion was the agreement of the parameters of the MS of the compound tmdergoing analysis with its structural characteristics and with the information given in the Hewlett-Packard MS Data Base [ 12].

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