The form of N supplied to the plant (NH4+ or NO3–) affects growth, morphology and a range of physiological processes in the plant. Little information is available concerning the effects of N form on development, production or quality of cut-flowers. The present study investigated for the first time the effects of N form and quantity on growth, flower production and flower quality of Ranunculus asiaticus L. The plants were cultivated in an inert mineral soilless medium (perlite) and were exposed to two levels of nitrogen fertilization (50 or 100 ppm) and three levels of NH +4 (10%, 20%, or 30%, under 100 ppm nitrogen fertilization). Larger shoots and increased shoot/root ratios were obtained in the lowest (50 ppm) N treatment. This treatment also excelled in flower yield production, resulting in higher numbers of total flower produced as well as higher numbers of long flowers. The results demonstrate an effect of N ferlilization treatments on cut-flower quality. Flowers grown under 50 ppm N application characterized by almost double vase life duration compared to flowers grown under the various 100 ppm N treatments. However, flower quantity and quality were not affected by the level of NH4 applied. The R. asiaticus L. root was less sensitive to the N fertilization treatments than its shoot. Contents of organic N, NO –3, P, K, Ca, Mg, Na, Cl, Fe, Cu, Zn, B, and Mo in the leaves were not affected by the fertilization treatments. Taken together, our results suggest a low requirement of R. asiaticus L. for N fertilization, and insensitivity to ammonium concentrations in the range of 10 to 30 ppm, 10% to 30% of the total N supplied. Detrimental effects in terms of growth, production and cut flower quality were apparent already under 100 ppm N supply.

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Zantedeschia (Fam. Araceae), a genus of 6 or 7 species, are all native to South Africa, They generally grow in wet, marshy land often at the edge of forests. Z. aethiopica is used in Israel for cut flower production, as well as for rhizome propagation. The crop is mainly grown in unheated greenhouses during winter and early spring. Annual production of Z. aethiopica has increased rapidly over the last few years. This paper reports results of a series of studies on the influence of planting depth and density, leaf removal and growth regulator treatments (gibberellic acid (GA) and benzyl adenine (BA)) on flowering and rhizome production. The objective was to define optimum growing procedures for the production of high yields of top quality Z. aethiopica flowers and rhizomes during the December to May winter growing season in Israel. We found that flower yield was high when rhizomes were planted at a depth of 10 cm below the soil surface. Deeper planting (20 cm) yielded highest rhizome weights, whereas planting at 10 cm, yielded the highest number of rhizomes. Changing planting density did not affect the number of flowers produced per plant, but close planting resulted in longer flower stems. Leaf removal increased flower yield. Dipping rhizomes in 350 ppm BA followed by a dip in 350 ppm GA 3 increased flower yield five fold over the control. However, a dip with only BA, yielded the same number of flowers, as the combined treatment. Although many malformed or green flowers developed as a result of GA 3 treatments, combination treatments with BA or BA alone reduced the extent of this problem.

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