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• Carbohydrate utilization of Erwinia amylovora in vitro

  31-34.

  M. Hevesi

  A. Farkas

  A. Kása

  Zs. Orosz-Kovács

  Views:

  153

  Nectar is a multi-component aqueous solution that promotes bacterial multiplication. The concentration of nectar in plant flowers is not stable since it is under the influence of environmental conditions, especially free moisture and relative humidity. Experiments were conducted with "artificial nectar" and directed along two lines: (1) determination of the optimal concentrations of carbohydrates for the growth of E. amylovora development (2) consumption of different carbohydrates besides basic sugars.

  Solutions of "artificial nectar" were prepared in different compositions by changing the dominance of basic sugars (fructose — glucose —sucrose) in proportions of 2:1:1, 1:2:1, 1:1:2 and between concentrations of 10-0.6% (diluted with Basal minimum broth) in order to determine optimal conditions for the development of E. amylovora.

  At a basic sugar concentration of 10% bacterial multiplication started and continued until I log degree (from 10⁶ to 10⁷ cfu/ml). At concentrations of 5% and 2,5 % cells developed with nearly the same kinetics (from 10⁶ to 8x10⁷ cfu/ml and from 10⁶ to 9x10⁷ cfu/ml, respectively). Multiplication was more pronounced and nearly the same at concentrations of 1.2 % and 0.6 % (from10⁶ to 2x10⁸ cfu/ml). At a basic sugar concentration 30% total sugars bacterial multiplication did not occur, while at 20 % it was negligible, not measurable photometrically.

  At minimal concentrations of F, G, S (between 1-0.1 %) bacterial cells were still able to multiply, producing organic acids from sugars.

  Our study showed that E. amylovora requires only a small amount of sugars (0.1%) for multiplication (acid production) while high concentrations inhibit multiplication. There was a negative correlation between sugar content and cell density. The optimal range of sugar concentration was at about 1%.

  Effect of "less frequent carbohydrates" to E. amylovora multiplication was also determined using the API 50 CH strip. We could provide information on utilization of 39 carbohydrates by the bacterium at different categories as follows: Not utilized-, Slowly and weakly utilized-, Slowly and completely utilized-, Quickly and completely utilized carbohydrates. We suppose that carbohydrates that belong to the latter two groups could play an important role as nectar components in promoting E. amylovora multiplication in the blossoms of pome fruit trees.

• Growing characteristics of apple cultivars in environmentally friendly growing systems

  7-10.

  P. Dremák

  Á. Csihon

  I. Gonda

  Views:

  226

  Nowadays the condition of the good saleability of the fruit is the application of controlled environmentally friendly technologies. Success of the growing is basically influenced by the production value of the cultivars, and their flexibility to the different technologies. In our examinations the effect of the integrated and organic farming  system has been evaluated on the growing characteristics of the apple cultivars. According to our results the trunk thickness of the trees both in the initial and both in the later bearing period is higher in the integratedproduction compared to the organic farming system. This differences most likely caused by the variance of the crop load.

• Assessment of apple varieties based on consumer judgement in integrated production for fresh consumption

  71-74.

  J. Felföldi

  T. Szabó

  J. Nyéki

  Z. Szabó

  M. Soltész

  F. Apáti

  Views:

  203

  In a former paper we treated the same relation comparing varieties frown in the biological or organic system of growing, now the tests have been performed with samples grown by the integrated system. The scores registered properties as taste, skin, colour, consistency and size. In addition, we also explored the relation between general impression and the individual properties.As first purpose, we started with collecting primary data on 15 samples taken from fruits grown by the integrated method and kept over 60–90 days in a store, then offered to the consumers. The test is based on an organoleptic assessment (records are registered in a questionary). The individual judgements are processed and coefficients of correlation between the traits (taste, skin, size, colour) calculated. The validity of the mathematically proved relations is considered to be decisive in judging the preferencial consumption of fruits.