Production and effects of volatile organic compounds during interspecific interactions

Competition between mycelia of saprotrophic cord-forming basidiomycetes occurs both within dead woody resources and in the soil-litter interface, and involves a variety of antagonistic mechanisms including the production of volatile organic compounds (VOCs). The antagonistic potential of VOC profiles from interactions in wood blocks and in soil microcosms was assessed using shared headspace experiments, and the profile of VOCs emitted over the course of interactions elucidated using solid phase microextraction (SPME) with gas chromatography-mass spectrometry (GC–MS). Quantitative and qualitative changes in VOC production occurred in interactions compared to self-pairing controls, with different VOC profiles from fungi growing in wood blocks compared to soil trays. There were both stimulatory and inhibitory effects of VOCs on target mycelial extension rate, hyphal coverage and fractal dimension. VOC-mediated effects were greater in self-pairing controls compared to interactions, and differed depending on the substratum in which the VOC-producing fungi were growing.     

燕山山脉一种香料型乳菇的香味成分分析

利用固相微萃取技术（SPME）偶联气相色谱-质谱（GC-MS）分析燕山山脉一种香料型乳菇——香亚环乳菇Lactarius subzonarius的挥发性成分。共检出25种挥发性成分,其中氧杂环化合物3种、醛类1种、酯类13种、烯烃类3种、芳香族化合物2种和烷烃类3种。具有葫芦巴感官气味的挥发性组分3-羟基-4,5-二甲基-2(5H)-呋喃酮的相对含量35.76%,该成分是其近缘种Lactarius helvus的主要香味化合物,故推测3-羟基-4,5-二甲基-2(5H)-呋喃酮是其关键香味成分。     

Mechanism of 2-acetyl-1-pyrroline biosynthesis in Bassia latifolia Roxb. flowers

The flowers of Bassia latifolia are known to contain 2-acetyl-1-pyrroline (2AP), the compound responsible for pleasant aroma in basmati and other scented rice. Four growth stages of Bassia flowers were identified and 2AP contents were analysed in each stage. It was found that 2AP (3.30 ppm) gets synthesized only in fleshy corolla of mature flowers (fourth stage). The activity of γ-aminobutyraldehyde dehydrogenase (AADH); an enzyme responsible for synthesis of γ-aminobutyricacid (GABA) from γ-aminobutyraldehyde (GABald) was assessed in these four stages. The AADH activity was absent in the fourth stage. It was concluded that ceased activity of AADH in fourth stage flowers leads to the accumulation of γ-aminobutyraldehyde which is cyclised spontaneously to Δ¹-pyrroline, the key precursor of 2AP. Δ¹-pyrroline further reacts unenzymatically with methylglyoxal to form 2AP.     

糖蜜草挥发性成分HS-SPME-GC-MS分析

本文首次采用顶空固相微萃取技术(HS-SPME)提取该植物挥发性成分,然后通过气质联用技术(GC-MS)结合保留指数以及标样对照对化学成分进行了定性,并通过峰面积归一化法计算出各组分的相对百分含量。试验确定了PDMS/DVB固相微萃取对糖蜜草挥发物的萃取效果最好,并从中鉴定出33种化合物占总挥发性成分的90.94%,主要为烷烃和萜烯类化合物。该研究为开发糖蜜草作为水稻螟虫的驱避植物进行害虫安全有效防治提供理论依据,并为驱避性挥发物的田间应用奠定基础。     

Investigations on the spontaneous emitted and hydrodistilled volatiles of Platycladus orientalis (L.) Franco grown in four different biogeographic zones of Jordan

The essential oil of the fresh leaves of Platycladus orientalis (L.), grown in four different biogeographic zones of Jordan,- (the Mediterranean, Irano-Turanian, Saharo-Arabian, and Sudanian penetration) -, were obtained by hydrodistillation and analysed by gas chromatography (GC) and gas chromatography-mass-spectrometry (GC/MS). The actual composition of the spontaneous emitted volatiles was obtained using the solid-phase-micro-extraction (SPME) method and investigated using the same chromatographic and spectroscopic methods. Hydrocarbon monoterpenes dominated the hydrodistilled oils and emissions of all regions. Bicyclic monoterpenes (sabinene, α-pinene, and α-thujene) and monocyclic α-terpinene were detected as the major constituents of the oils and emissions. Additionally, hierarchical cluster analysis (HCA) revealed that the clustering is based on the region of collection rather than the applied methodology. Differences were observed in the quantity of the obtained oils (P-values <0.01); the highest amount of volatile oil was obtained from samples grown in the Irano-Turanian biogeographic zone.     

Volatile Compounds of Viola odorata Absolutes: Identification of Odorant Active Markers to Distinguish Plants Originating from France and Egypt

Absolutes isolated from Viola odorata leaves, valuable materials for the flavor and fragrance industry, were studied. Violets are mainly cultivated in France and Egypt and extracted locally. The absolutes of the two origins showed different olfactory profiles both in top and heart notes, as evidenced by sensory analysis. The aims of this study were i) to characterize the volatile compounds, ii) to determine the odorant‐active ones, and iii) to identify some markers of the plant origin. Two complementary analytical methods were used for these purposes, i.e., headspace solid‐phase microextraction (HS‐SPME) using different fiber coatings followed by GC/MS analysis and gas chromatography – olfactometry/mass spectrometry (GC‐O/MS) applied to violet leaf extracts. From a total of 70 identified compounds, 61 have never been reported so far for this species, 17 compounds were characterized by both techniques (with seven among them known from the literature), 23 compounds were solely identified by HS‐SPME GC/MS (among them only two being already mentioned as components of violet absolutes in the literature), and, finally, 30 compounds were only identified by GC‐O/MS. According to the HS‐SPME GC/MS analyses, ethyl hexanoate and (2E,6Z)‐nona‐2,6‐dienol were specific volatile compounds of the sample with French origin, while (E,E)‐hepta‐2,4‐dienal, hexanoic acid, limonene, tridecane, and eugenol were specific of the samples with Egyptian origin. Additional compounds that were not detected by HS‐SPME GC/MS analysis were revealed by GC‐O analyses, some of them being markers of origin. Pent‐1‐en‐3‐ol, 3‐methylbut‐2‐enal, 2‐methoxy‐3‐(1‐methylethyl)pyrazine, 4‐ethylbenzaldehyde, β‐phenethyl formate, and 2‐methoxy‐3‐(2‐methylpropyl)pyrazine revealed to be odorant markers of the French sample, whereas cis‐rose oxide, trans‐rose oxide, and 3,5,5‐trimethylcyclohex‐2‐enone were odorant markers of the Egyptian samples.     

Pollen Diversity and Volatile Variability of Honey from Corsican Anthyllis hermanniae L. Habitat

Melissopalynological, physicochemical, and volatile analyses of 29 samples of Corsican ‘summer maquis’ honey were performed. The pollen spectrum was characterized by a wide diversity of nectariferous and/or polleniferous taxa. The most important were Anthyllis hermanniae and Rubus sp., associated with some endemic taxa. Castanea sativa was also determined in these honeys with a great variation. The volatile fraction was characterized by 37 compounds and dominated by phenolic aldehydes and linear acids. The major compounds were phenylacetaldehyde, benzaldehyde, and nonanoic acid. Statistical analysis of pollen and volatile data showed that 18 samples were characterized by a high abundance of phenylacetaldehyde, which might relate to the high amount of A. hermanniae and Rubus sp. Eleven other samples displayed a higher proportion of phenolic ketones and linear acids, which characterized the nectar contribution of C. sativa and Thymus herba‐barona, respectively.     

基于 HS-SPME/GC-MS 分析山茶品种‘克瑞墨大牡丹’花器官香气成分简

采用顶空固相微萃取法（HS-SPME）提取了山茶品种‘克瑞墨大牡丹’不同花器官自然挥发的花香挥发油,并用气相色谱—质谱联用仪（GC-MS）分析了花香成分。分别从整花、花瓣、雄蕊中检测到了89、80、21种化合物。花香成分主要由萜类、芳香族化合物、脂肪族化合物等组成,其中以单萜中的芳樟醇相对含量最高,以下依次为顺式氧化芳樟醇、水杨酸甲酯、十四烷等。花瓣和雄蕊中花香成分有较大差别,芳樟醇在花瓣和雄蕊中均占首位,相对含量分别为15.12%和63.97%,雄蕊缺乏烷烃和芳香烃。同一朵花所有花瓣的花香绝对挥发量是所有雄蕊的3倍以上,但质量相同时雄蕊的挥发量却明显高于花瓣,表明花瓣和雄蕊对‘克瑞墨大牡丹’的花香具有同样重要的贡献。     

营养液供应量对番茄产量、品质和挥发性物质的影响

为探讨基质栽培条件下不同供应量的营养液对番茄果实产量、品质和挥发性物质的影响,以"HL2109"番茄为试验材料,设置4个处理.对照:每株全生育期只浇清水,共计117 L;T1:每株全生育期共浇营养液39.0 L;T_2:每株全生育期共浇营养液58.5 L;T_3:每株全生育期共浇营养液117 L,利用化学方法及固相微萃取-气相色谱-质谱联用(SPME-GC-MS)技术测定番茄果实品质和挥发性物质.结果表明:随着营养液供应量的增加,番茄单株产量和产量呈先升后降的变化趋势,以T_2处理最大,达到每株2.53 kg;T_1、T_2、T_3处理的番茄产量分别比对照增加了29.3%、72.6%、47.0%;T_1处理的灌溉水分利用效率最大,T_2次之,两者差异不显著.T_2处理番茄果实的可溶性固形物含量、糖酸比最高,果实的风味品质显著提升.随着营养液供应量的增加,果实的可溶性蛋白、抗坏血酸含量逐渐增加,可溶性总糖、还原糖含量呈现先增加后减少的趋势,均以T_2处理最高.利用GC-MS共检测出挥发性物质69种,T_1、T_2、T_3的果实挥发性物质总含量高于对照,表现为T_2>T_1>T_3>对照.其中T_2、T_1和T_3处理果实挥发性物质总含量分别为6971、6095和4070μg·kg^-1,比对照分别增加了1.97、1.56和0.73倍;随着营养液供应量的增加,1-戊烯-3-酮、6-甲基-5-庚烯-2-酮、己醛、己酸、苯乙醛、顺-3-己烯醛等均以T_2处理的含量最高,并且T_2处理果实的特征挥发性物质含量、挥发性物质数量和总含量都最高.在本试验条件下,采用每株全生育期浇营养液58.5 L处理能够提高果实品质和挥发性物质含量,效果最佳.