Composition Of Leaf Volatiles Research Articles

Secondary Metabolism and Plant Growth of Piper divaricatum (Piperaceae) Inoculated with Arbuscular Mycorrhizal Fungi and Phosphorus Supplementation

Arbuscular mycorrhizal fungi (AMF) species and/or phosphorus addition in the soil can affect secondary metabolism production and growth in plants. This study evaluated these effects on Piper divaricatum culture, which presents an essential oil rich in phenylpropanoids. Growth parameters, leaf volatile composition, total phenolic content, and the enzymatic activity of lipoxygenase (LOX) and phenylalanine ammonia-lyase (PAL) were monitored. At 90 days post inoculation (dpi), the treatments with AMF and AMF + P were more effective in terms of the number and biomass of leaves. In addition, the AMF group had increased plant height and root length. Phenylpropanoid and methyl eugenol contents were higher at 30 dpi in the P and AMF + P association treatments. However, at 90 dpi, the plants with P addition at 20 mg·dm−3 and AMF + 200 mg of P·dm−3 showed higher phenolic contents and PAL activity, respectively. All treatments increased LOX activity, especially with P addition at 200 mg·dm−3. These results demonstrate that P and AMF can be applied to optimize leaf biomass and volatile compound production in P. divaricatum.

Leaf Essential Oil of Cultivated Pimenta Racemosa (Mill.) J.W. Moore from North India: Distribution of Phenylpropanoids and Chiral Terpenoids

In this work, cultivated Pimenta racemosa from North Indian plains was studied for its leaf volatile composition twice in year at two distinct seasons (spring and autumn) using GC-FID, enantio-GC-FID, GC/MS and 1H-, 13C-NMR and DEPT experiments. Phenylpropanoid was the abundant class of compounds represented by eugenol (72.9%) followed by chavicol (7.7%) whereas myrcene (9.6%) and limonene (3.8%) were identified as the most exclusive terpene constituents in spring collection. The autumn sample was recorded with highest eugenol (92.9%) proportion. Notably, presence of chavicol differentiates this oil from Pimenta dioica. An enantiomeric excess for (S)-(-)-limonene (41.1-45.3%) and (R)-(-)-linalool (86.7-89.9%) was recorded over (R)-(+)-limonene and (S)-(+)-linalool, respectively when separated on 6-tert-butyldimethylsilyl-2,3-diethyl-β-cyclodextrin chiral phase. Moreover, both the monoterpene derivatives occur as enantiomeric mixture in P. racemosa leaf essential oil.

Differentiation of Fruiting and Non-fruiting Pimenta dioica (L.) Merr. Trees Based on Composition of Leaf Volatiles

Leaf oil from fruiting female and non-fruiting male Pimenta dioica (L.) Merr. trees, were analyzed by GC. Oil yields from male pimento trees (2.13%) were typically lower than that for female trees (2.67%). Non-fruiting and fruiting trees contained the same volatile components with different relative abundances. The composition of eugenol (p< 0.01), and myrcene, α-phellandrene, γ- terpinene, terpinolene and α-thujene (p< 0.005) were significantly different in the female versus the male pimento trees. Characteristic monoterpenoid profiles were observed for the fruiting and non-fruiting pimento trees which could be used for the early prediction of the berry bearing ability of pimento trees.