ACTA AGRONOMICA TOMUS 33. (A MTA AGRÁRTUDOMÁNYI KÖZLEMÉNYEI, 1984)

1984 / 1-2. szám - JUHÁSZ, O.-KOZMA, P.-POLYÁK, D.: Nitrogen status of grape-vines as reflected by the arginine content of the fruit

Acta Agronomien Academiae Scientiarum Hungaricae, Tomus 33 (1 — 2), pp. 3—17 (1984) NITROGEN STATUS OF GRAPE-VINES AS REFLECTED BY THE ARGININE CONTENT OF THE FRUIT By JUHÁSZ, О., KOZMA, P., POLYÁK, D. DEPARTMENT OF VINE CROWING, UNIVERSITY OF HORTICULTURE, BUDAPEST Changes in the free amino acid composition, particularly the arginine content, in the fruit of four wine-grape varieties (Rizlingszilváni, Ezerjó. Hárslevelű and Olaszriz­ling) during ripening in response to nitrogen fertilization were studied. Must preserved with merthiolate was used for the analyses after adequate purification and concentra­tion) procedures. The quantity of free amino acids was determined using an automatic amino acid analyser. On the basis of results obtained over three years (1976, 1977, 1978) it can be established that of all the free amino acids it is arginine that accumulates in the largest quantities during ripening (correlation coefficient r = 0.950). In 1976 and 1977, when the ecological conditions were more favourable, the effect of nitrogen was better felt than in the cooler and rainier year of 1978. In the fruit of the variety Rizlingszilváni the nitrogen application resulted in a relatively high rate of arginine accumulation. Considering the fact that the quantity of arginine increases consider­ably in the fruit of grape-vines better supplied with nitrogen, the arginine content could be very useful as an indicator of the nitrogen status of the vine. Introduction Among the major mineral elements, nitrogen plays the most important role in the metabolic processes of plants; in particular, its incorporation into proteins and nucleic acids is of primary importance from the point of view of plant life. An adequate supply of nitrogen results in intensive vegetative development. At the same time the unfavourable effects of nitrogen must also be taken into account; namely, higher rates of nitrogen application prolong the growth period and delay the ripening of the fruit. Disturbances in the nitrogen supply, nitrogen deficiency in particular, often fail to be noticed in the vine until they are at an advanced stage, in which case inter­vention fails to produce the expected result. It thus proved necessary to elaborate a rapid, precise standard method to indicate the nutrient deficiencies of the grape-vine in good time. Leaf analysis is a suitable method for determining the nutrient status of the soil and the plant, and the effect of fertilization (GRIEGEL 1968, LEVY— CHALEH 1972, KOZMA—POLYÁK 1972). After statistically processing the information obtained in the course of the experiments it can be established that the average NPK and Mg contents of leaves originating from different vine regions very considerably, and the differences reflect the effects of climatic, cultivation and economic factors. Acta Agronomica Academiae Scientiarum Hungaricae 33, 1984 1*

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