IMPACT OF NITROGEN FERTILIZATION ON GROWTH AND PHOTOSYNTHETIC ACTIVITY OF WALNUT PLANTING MATERIAL (JUGLANS REGIA L.), CULTIVATED IN CONTAINERS.

The object of the experiment was the walnut cultivar Izvor 10, grafted on a walnut rootstock (Juglans regia L.). The plants were propagated by the "Hot Callus" method and grown in containers (50 l) with peat-pearlite mixture (2:1). The impact of nitrogen fertilization on the growth and the physiological characteristics of young walnut plants was studied. Variants of the experiment were: Control (not-fertilized), Variant II - 2 g N / container and Variant III - 4 g N container. The height of the fertilized plants varied from 86 to 107 cm and the stem diameter - from 12.76 to 13.61 mm, while the control plants reached average values of 49.33 cm in height and 10.53 mm in stem diameter and the differences were statistically proven. It was found that fertilization with ammonium nitrate (NH4NO3), in the range of 2 - 4g N/container contributes to a more efficient development and structuring of the photosynthetic apparatus, which, on the other hand, is a prerequisite for more intensive photoassimilation and biomass accumulation. It was concluded that fertilization is mandatory for the production of walnut planting material in containers. [ABSTRACT FROM AUTHOR]