Seasonal variation in the composition of the volatile oil of the leaves, buds, and twigs of white spruce (Picea glauca)

摘要

Gas chromatographic analysis of the volatile terpenes of the leaves, buds, and twigs of white spruce has confirmed that major changes take place only in the new shoots during the early part of summer. Minor changes were recorded for the older shoots during the same period. The relative amounts of beta;-pinene, limonene, and myrcene in the volatile oil of the buds change significantly during fall and winter. In contrast, the volatile oil of the leaves and twigs remains constant in quantitative composition during late summer, fall, and winter. The sequence in which the relative amounts of each terpene are laid down in the new growth is complex and no correlation with accepted biosynthetic pathways for monoterpenes could be found. During May substantial amounts of sesquiterpenes are present in the new growth, but these appear to be metabolized further as the summer progresses. The implications for chemosystematic studies are discussed.