Influence of Cultivar and Harvest Year on the Volatile Profiles of Leaves and Roots of Carrots (Daucus carota spp. sativus Hoffm.)

Abstract

The focus of the present work centers on the diversity of volatile patterns of carrots. In total 15 main volatiles were semiquantified in leaves and roots using isolation by headspace solid phase microextraction followed by gas chromatography with FID and MS detection. Significant differences in the main number of compounds were detected between the cultivars as well as the years. Genotype-environment interactions (G × E) are discussed. The most abundant metabolites, β-myrcene (leaves) and terpinolene (roots), differ in the sum of all interactions (cultivar × harvest year) by a factor of 22 and 62, respectively. A statistical test indicates significant metabolic differences between cultivars for nine volatiles in leaves and 10 in roots. In contrast to others the volatiles α-pinene, γ-terpinene, limonene, and myristicine in leaves as well as β-pinene, humulene, and bornyl acetate in roots are relatively stable over years. A correlation analysis shows no strict clustering regarding root color. While the biosynthesis in leaves and roots is independent between these two organs for nine of the 15 volatiles, a significant correlation of the myristicine content between leaves and roots was determined, which suggests the use of this compound as a bitter marker in carrot breeding.

The Terpene Synthase Gene Family of Carrot (Daucus carota L.): Identification of QTLs and Candidate Genes Associated with Terpenoid Volatile Compounds

“…Five of the compounds (sabinene, β-caryophyllene, ocimene, a-pinene and terpinen-4-ol) show correlations which are significant at a level of p < 0.05. This is in accordance with earlier results for sabinene and β-caryophyllene (Ulrich et al, 2015 ), the substances with the highest correlation between leaves and roots.…”

“…In combination with olfactometry, GC led to the identification of substances as “character impact compounds” characterized by flavor dilution factors greater than 1 (Edelenbos et al, 2003 ). For some compounds also strong correlations of the content in leaves and roots have been shown (Ulrich et al, 2015 ).…”

“…A more detailed investigation of carrot root tissues revealed that the biosynthesis of terpenes is mainly localized in the phloem (Hampel et al, 2005 ). Using headspace solid phase microextraction followed by gas chromatography with flame ionization detection and mass spectrography (HS-SPME-GC-FID and MS), Ulrich et al ( 2015 ) analyzed the diversity of terpene volatile patterns of carrot roots and leaves. In combination with olfactometry, GC led to the identification of substances as “character impact compounds” characterized by flavor dilution factors greater than 1 (Edelenbos et al, 2003 ).…”

Link between carrot leaf secondary metabolites and resistance to Alternaria dauci

“…The analyses of environment effects on the overall accumulation level of secondary metabolites per sub-family (chlorogenic acids, flavones, mono- and sesquiterpenes) revealed statistical differences between the three environments studied (Angers tunnel, Blagon field and Ychoux field; Table 1 ). This has already been described in a very high number of papers where biotic or abiotic environmental factors are cited as responsible for fluctuations in the accumulation of plant secondary metabolites, even for the carrot species 33 , 36 – 39 . In the present study, the overall accumulation level of secondary metabolites could also be explained by a combination of different biotic and abiotic factors, however we were not able to distinguish one from the other, and the main focus of the present paper is genetics.…”

“…Ulrich et al . 33 reported germacrene, β-caryophyllene, limonene, β-myrcene, sabinene and α-pinene as major compounds in 10 carrot cultivars, and finally, Keilwagen et al . 34 reported β-myrcene, β-caryophyllene and limonene as the most abundant compounds in leaves of a panel of 85 carrot cultivars and accessions.…”