Rafidain Journal of Science

Abstract

The research discusses the use of flashes of ultraviolet-C rays in inducing resistance against viral pathogens and the possibility of its employment in covered houses or garden nurseries. A number of tomato and tobacco plants of type Nicotiana tabacum, uder protected cultivation conditions, were exposed to UV-C rays at wavelengths 200-280 nm using an electronic LED lamp, for 5 and 10 minutes, all plants were inoculated 48 hours after the last exposure to UV rays. The number and size of local lesions were calculated on the leaves of inoculated tobacco plants, as well as monitoring the development of symptoms on tomato plants inoculated with the virus for 12 days of inoculation, and the virus concentration was estimated based on the amount of absorbance at 405 nm by ELISA test. The results indicated that the ultraviolet rays used enhanced the plant's resistance to viral infection through a noticeable increase in the enzyme peroxidase, as it reached (59220 nanometers) in the treated plants compared to the untreated plants that were (28,016 nanometers). The irradiation for the first five minutes had a higher effect than the longer irradiation that lasted for ten minutes, in addition to that the irradiation for intermittent periods and for a short period was better than the continuous exposure for one time. It was found that the leaves far from the radiation exposure area acquired an inducible character of resistance against the pathogen.