摘要：The study focused on determining the effect of an exogenous growth regulator on the activity of nitrate reductase and the content of plastid pigments in lucerne. In March 2014, a pot experiment was conducted to grow Medicago x varia T. Martyn in a growth room under controlled conditions (temperature 24±2/16±2ºC, photoperiod 16/8 h, light intensity of 200 µmol·m-2·s-1 achieved through the use of high-pressure sodium lamps, humidity 40%). The experiment was carried out in 40 pots, four pots for each variant and 3 plants in each pot. The experimental factor was an own preparation (exogenous growth regulator) protected by the Polish Patent Office (number of invention: P/407/790). The regulator contained synthetic auxin, cytokinin and titanium in a form of chelate. Depending on the experimental variant, spraying with the regulator was applied at the sixth true leaf stage and at the first flower bud stage. The control plants were treated with distilled water. The best results were obtained after spraying plants with the regulator twice: at the sixth true leaf stage and at the first flower bud stage. Only in the case of nitrate reductase activity in the roots and the ratio of total chlorophyll content to carotenoids, the highest values were obtained after using the regulator once.
