Content and composition of dill herb oil in the whole plant and the different plant parts during crop development

Abstract

Abstract Dill herb oil samples were obtained from 2 Canterbury commercial crops, between flowering and full seed ripeness. Data on the essential oil content of whole plants and the oil composition are related to different stages of seed development and maturation. The best yield of oil with maximal carvone content was obtained when the seeds of the primary umbels showed the first red colouration. Limonene and phellandrene were found in stems, leaves, and primary and secondary umbels but were highest in stems and leaves. Anethofuran was a major component of the oil from umbels at flowering but declined during seed maturation. The characterisation of anethofuran is described. Carvone was present only in the developing umbels until senescence of the whole plant when it was found in all tissues. Within the umbels, the carvone was present in the seeds only and not the pedicels. Contributions to the whole plant's total fresh weight, oil content, and oil composition by the different parts of the crop plants were calculated. On a fresh weight basis, the umbels contributed more of the total oil and more of each of the 4 major oil components than did the stems or leaves. This was so at both the first flowering and recommended harvest stages. It is suggested that maximum umbel production should be encouraged for both ‘sweet’ and ‘high carvone’ oils.