| heal.abstract |
The effect of four levels of nitrogen (N) application (3.2, 16.2, 32.4, and 48.6 g m-2) on the biomass and concentration and composition of essential oils of three parsley types (plain leaf, turnip-rooted, curl leaf) was investigated in order to determine the optimum N level for oil production by this crop. The concentration of essential oils in the roots and leaves of plain leaf parsley and turnip-rooted parsley was not affected by N application, but decreased with increasing N rate in curl leaf parsley. However, because the mean foliage biomass for all three types was about 2.5 times higher at 16.2 g m -2 N than in the low-N-rate treatment, the mean foliar oil yield increased from 0.68 to 1.38 g m-2. Root biomass increased by a factor of 1.7 at 16.2 g m-2 N (compared to the low-N-rate treatment), but oil yield increased only marginally from 0.3 to 0.4 g m-2. The composition of the essential oils of roots and leaves differed between parsley types. Increasing N application caused a reduction in the percentage of β-phellandrene in the essential oils of parsley leaves. In turnip-rooted parsley, increasing N caused a reduction in the percentage of myristicin and apiole. Because these three components of the essential oils contribute to parsley aroma, it may be concluded that although application of N fertilizer leads to higher parsley biomass and oil yield per plant, the essential oil components may change and aroma quality may be affected negatively. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA. |
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