Abstract

ABSTRACT: The use of growth regulators in commercial production of bulb plants such as narcissus has been limited, but these chemicals can improve flower quality and vegetative growth by inducing enzyme activity and also nutrient assimilation. The objective of the present experiment was to evaluate the influence of nitrogen and cytokinin on growth and nitrate reductase activity of narcissus (Narcissus tazetta L.) under ̒ Behbahan̕ climatic condition (Khuzestan, South west of Iran). Effects of four levels of benzyl adenine (0, 100, 200 and 500 mgl-1) and potassium nitrate (0, 1, 2 and 4 gKg-1 soil) on Narcissus grown in pot containing soil were studied. Results showed that leaf and flower development increased with an increase in BA concentration from 100 to 500 mgl-1, but magnitude of this response varied among potassium nitrate levels. The increase in BA concentrations induced significant decrease in leaf nitrate content. Flowering time, leaf nitrate content and nitrate reductase activity decreased with an increase in BA and potassium nitrate levels, while there were no significant effect of BA and potassium nitrate interaction on floret numbers. Finally, results suggest that Benzyl adenine and nitrogen have the potential to be an alternative nutrient source for narcissus, though further research should continue to select the suitable treatment of potassium nitrate × Benzyl adenine in narcissus cut flower production. Keywords: Benzyl Adenine, daffodil )Narcissus tazetta), growth, Nitrate, Nitrate reductase enzyme