EFFECTS OF AGROCHEMICAL PROPERTIES, FERTILIZATION AND GROWTH STAGE ON THE CONTENTS OF NITRATES AND THE NITRATE REDUCTASE ACTIVITY IN ALFALFA LEAVES
Elmi JUSUFI, Bedri GJURECI
Abstract
Alfalfa (Banat ZMS II) was grown in vegetation pots with 12 kg of air-dry soil from different localities with known contents of total nitrogen, phosphorus, potassium, and molybdenum. The content of the same nutrients is also known in the dry mass of the experimental alfalfa.
The measured nitrates showed a dependence on the content of N, P, K and Mo in the soil. In the unfertilized plants, in the pre-flowering phase, a higher nitrate content was measured in the leaves of the Jegunovce and Raduša localities (16.01; 16.10 μmolNO3- g/FW-1) that is, of the fertilizer plants in the leaves of Saraj and Raduša (22.12; 19.58 μmolNO3- g/FW-1). In the flowering phase, the average nitrate content in the unfertilized ones was lower by 26.1%, and in the fertilized plants by 33.54%.
During before flowering phase, higher nitrate reductase activity (in vivo) was measured in fresh leaf mass from the Jegunovce and Raduša localities (614.39; 605.41 nmol NO2- g/FW-1/h-1), while lower in the leaves of Saraj (529.84 nmol NO2- g/FW-1/h-1). Under in vitro conditions, higher activity in the leaves of Jegunovce (728.10 nmol NO2- g/FW-1/h-1), and lower in those of Kodzilari (560.29 nmol NO2- g/FW-1/h-1).
In the flowering phase, the reduced enzyme activity by an average of 56.29% is accompanied by a decrease in the amount of nitrates and the mentioned biogenic elements in the dry mass of the leaves.
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