Measurement of monoterpene hydrocarbon levels in vapor phase surrounding single-leaf pinyon (Pinus monophylla Torr. & Frem.: Pinaceae) understory litter

Abstract

A headspace air-sampling experiment was performed in the laboratory to determine the identity and concentrations of monoterpene hydrocarbons that could be attained in the vapor phase surrounding single-leaf pinyon pine (Pinus monophylla Torr. & Frem.) understory litter using controlled air collection conditions at a simulated field temperature of 37.8°C. The total monoterpene hydrocarbon content in 21 sequential samples of air collected from a sealed glass carboy packed with 1.44 kg of single-leaf pinyon litter equivalent to a bulk density of 0.15 g/cm(3) averaged 3.56 ± 1.04 mg/liter. The monoterpenesα-pinene and camphene were present in the vapor phase at the highest concentrations, averaging 2.40±0.64 and 0.68±0.22 mg/ liter, respectively. Myrcene,β-pinene, 3-carene,β-phellandrene, andγ-terpinene were all present at average concentrations below 0.30 mg/liter. The first two traps of the sequential air samples yielded the highest concentrations for the monoterpene hydrocarbons; however, the average total levels were relatively stable throughout the remaining 19 traps. Therefore, the data indicate that these hydrocarbons volatilize from the source pinyon litter and maintain an equilibrium in the vapor phase. Although this analysis was conducted using an artificial system, combined with results from our previous studies, mounting evidence indicates that monoterpene hydrocarbons present in the vapor phase of the single-leaf pinyon understory may be toxic to a variety of native plant species and thus further implicates allelopathy as a significant contributor to the observed patterning of associated vegetation in these forests.

Nitrogen transformations in boreal forest soils—does composition of plant secondary compounds give any explanations?

“…Loss of monoterpenes from litter probably occurs through gradual diffusion into the surrounding atmosphere (Wilt et al 1993b;Van Roon et al 2005). The total content of monoterpenes in the litter samples was shown to vary substantially, which affects the concentrations of different monoterpenes in the air phase (Wilt et al 1988;White 1991;Strömvall and Peterson 2000).…”

“…The total content of monoterpenes in the litter samples was shown to vary substantially, which affects the concentrations of different monoterpenes in the air phase (Wilt et al 1988;White 1991;Strömvall and Peterson 2000). In addition, vapor pressure and the boiling point of the particular monoterpene as well as the temperature, water saturation and organic carbon content of the soil may also have an effect on monoterpene concentrations (Wilt et al 1993b;Van Roon et al 2005). In freshly fallen needle litter from Scots pine and two spruce species the majority of the monoterpene content of coniferous needle litter was lost in half a year (Ludley et al 2009a).…”

“…The main monoterpene present in Norway spruce and Scots pine is α-pinene (Manninen et al 2002), which also has the lowest boiling point as well as the highest vapor pressure at 38°C (Wilt et al 1993b). Therefore, it was not surprising that α-pinene was the most abundant monoterpene in the forest soil atmosphere (Fig.…”

“…Wilt et al (1993b) incubated litter from single-leaf pinyon (Pinus monophylla Torr & Frém.) in a carboy at 38°C; the concentration of monoterpenes in the air of the carboy was 3,560 mg m −3 .…”

Biological Control of Plant Pathogens by Antibiotic-Producing Bacteria

“…Some other similar groups, such as phenolic compounds, quinones, peptides and volatile compounds are identified as allelochemicals or antibiotics (3, 30,[60][61][62][63][64][65][66][67][68].…”