IDENTIFICATION AND ELIMINATION OF "SLOWLY GROWING" BACTERIA FROM A MICROPROPAGATED GERBERA

Four methods of testing for bacteria presence were compared in presented experiments : toutching of a testing solid medium/King B/ with a shoot base, immersing of a whole shoot in a liquide medium, homogenization of shoot and plating of a homogenite on a solid medium and plating of remnants which remain after division of multiplantlets on a solid medium. The last method is the most efficient. 15 strains of bacteria were isolated from initial gerbera explants by the application of this method. 7 of them were identified as the genus Bacillus, between them 3 as B. polimyxa; 5 were found one of the Coryneforms and 2 were described as Pseudomonas fluorescens and P. putida. Antibiograms with 16 antibiotics were prepared for these bacteria. All of them were suscestible only on doxycycline.

Doxycycline and rifampicine were added in different concentrations to a gerbera multiplication medium in order to eliminate bacteria present in micropropagated tissues. The antibiotics acted bacteriostatically but Incyte used at a concentration of 1 : 1 : 8 killed bacteria in about 28 % washed transplanted shoots. Treatment with Incyte didn't lower the multiplication coefficient of treated shoots.