The effect of differentiated nitrogen fertilization on nitrate reduction in broccoli
heads of ‘Lord F1’ in spring cultivation
Renata Wojciechowska, Stanisław Rożek, Maria Leja
Department of Plant Physiology
Agricultural University in Kraków
29 Listopada 54, 31-425 Kraków, Poland
Broccoli (Brassica oleracea L. var. italica) ‘Lord F1’
was grown at the Agricultural University experimental farm in the Cracow area in the spring growing cycle of three
successive years. In harvested broccoli heads activities of nitrate reductase (NR) and nitrite reductase (NiR) as
well as NO3- and
NH4+ ions contents were determined.
The nitrogen fertilizer rate introduced into the soil did not significantly affect the average activity of both
enzymes, responsible for nitrate reduction. The application of mineral N increased nitrate level in broccoli
heads, however, decreased NH4+ content.
The foliar nutrition with 2% urea, applied five times during the growing period significantly increased
the activity of NR in all investigated treatments, but did not influence the activity of NiR as compared with
non-fed plants. Foliar application lowered the average nitrate content in broccoli heads but the significant
effect was found only in the case of the full rate of mineral N. This factor did not significantly affect
ammonium ions content in the analyzed plant organs. Strong interdependence was observed
between the activity of the determined enzymes, as well as of NO3-
and NH4+ and the weather
conditions accompanying the plant cultivation in the particular years of experiment.
Wojciechowska R., Rożek S., Leja M., 2006. The effect of differentiated nitrogen fertilization
on nitrate reduction in broccoli heads of ‘Lord F1’ in spring
cultivation. Folia Horticulturae 18/1: 101-110.