Verstärkung der antiphytoviralen Wirkung von 2,4‐Dioxohexahydro‐l,3,5‐triazin durch Kombination mit Verbindungen mit Guanidinstruktur

Abstract

Abstract Intensified antiphytoviral activity of 2,4‐dioxohexahydro‐l,3,5‐triazine by combination with guanidines Combined application of the antiphytoviral compound 2,4‐dioxohexahydro‐l,3,5 triazine (DHT) and different guanidines (GDs) that were either unsubstituted or substituted only by low‐molecular substituents reduced the concentration of potato virus χ (PVX) in leaves or Nicotiana tabacum L. cv. Samsun much more than application of either agent alone. In secondarily PVX‐infected leaves, the activity of 2,4‐dioxohexahydro‐ 1,3,5‐triazine was increased by a larger number of GDs and to a greater degree than in inoculated ones. The activities of GDs against tobacco mosaic virus (TMV) in Nicotiana tabacum L. cv. Samsun as well as against brome grass mosaic virus (BRV) in Hordeum vulgare L. cv Vogelsanger Gold were only insignificantly increased by combination with DHT. On the other hand, in experiments with so‐called identical potato eye cuttings, in which several eye cuttings were obtained from each potato tuber, one serving as a control and the others being treated with DHT, N‐cyano guanidine or a combination of these substances, the number of cuttings with symptoms of potato leaf‐roll virus (PLRV) could be much more greatly reduced by the combination than by the individual preparations. The number of cuttings with symptoms of potato virus Y and potato virus A was significantly reduced by treatment with the combined preparation, but not by treatment with DHT or N‐cyano guanidine alone. Additional investigation with N‐cyano‐GD, and, beside this, with acetyl‐GD and N N′ N triamino‐GD indicated a close correlation between the diminution of numbers of potato eye cuttings with virus symptoms and the increase in tuber weight. The greater the reduction in the number of cuttings showing virus symptoms, the greater was the increase in tuber weight. These relationships were observed even in those cases where controls had been treated with ammonium nitrate solutions whose N contents equivalent to the N contents of the preparations. The observed effects of the preparations therefore are not attributable to N‐fertilizing effects.