Uptake, translocation and fractionation of nitrogen in narcissus organs by using 15N

Narcissus L. cv. 'Garden Giant' bulbs were planted in hydroponics solution. At different stages of growth (15)N[(15)NO(3)(-)+(15)NH(4)(+)] was added to investigate nitrogen uptake, translocation and fractionation in the organs. Most of the nitrogen (ca. 90%) distributed in the scales at planting. The average (15)N absorbed from the culture solution was about 175 mg/plant during winter, 74 mg/plant from sprouting until flower senescence and 72 mg/plant from flower senescence to harvest. The absorbed-N was abundant in roots during winter and translocated into other organs after sprouting. The shoot played a role of sink organ to obtain nitrogen until flower senescence. Thereafter, the nitrogen content in the new scales increased continuously. At harvest, 71% of the absorbed-N during the winter, 69% of the absorbed-N from sprouting to flower senescence and 78% of the absorbed-N from flower senescence to harvest had translocated and accumulated in the new scales for use in next crop. Nitrogen-free treatment confirmed that additional nitrogen supply is very important, because the nitrogen shortage of the nitrogen-free solution inhibited the growth of narcissus.