Z Katedry Sadownictwa i Przyrodniczych Podstaw Ogrodnictwa
Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Abstract. The effect of nitrogen fertilization on low molecular weight thiols, ascorbate, glutathione reductase and ascorbate peroxidase in edible parts of broccoli and cauliflower were investigated. Four levels of nitrogen: 40 (control group), 100, 200 and 300 mg N ∙ dm-3 and two types of soil: podsol sandy soil and silty loam alluvial soil were tested. Total glutathione content increased with the increasing N level. Fertilization had no significant effect on ascorbate content. The antioxidant potential in broccoli ‘Fiesta F1’ was significantly higher than cauliflower ‘Lateman’.
Key words:
thiol compound, ascorbate, glutathione reductase, ascorbate peroxidase, nitrogen, broccoli, cauliflower
Summary
Effect of nitrogen fertilization on cysteine, ү–glutamylcysteine, glutathione, ascorbate and some enzyme activity was investigated. Four levels of nitrogen: 40 (control group), 100, 200 and 300 mg N . dm-3 and two types of soil: podsol sandy soil and silty loam alluvial soil were tested. Edible part of broccoli ‘Fiesta F1’ and cauliflower: ‘Lateman’ were analyzed. Vegetables were at the stage of commercial maturity. Fertilization had a significant effect on glutathione content and on activity of glutathione reductase and ascorbate peroxidase. The cysteine and
ү–glutamylcysteine content depended on the type of soil. The decrease of antioxidant component was usually observed at the level of 100 mg N ∙ dm-3 in the soil in comparison with control plants. High levels of nitrogen in the soil (200, 300 mg N ∙ dm-3) either caused a increase of antioxidant content or had no effect on the level of those phytochemicals. The antioxidant potential in broccoli ‘Fiesta F1’ was significantly higher than in cauliflower ‘Lateman’. Moreover, plants grown on podsol sandy soil had higher content of low molecular weigh thiols and ascorbate than those grown on silty loam alluvial soil.