Volatile Organic Compounds and Their Roles in Bacteriostasis in Five Conifer Species

In order to make clear the functions of plant volatile organic compounds (VOCs) on bacteriostasis and air decontamination, we analyzed the composition and content of VOCs in Pinus tabulaeformis Carr., P. bungeana Zucc., Sabina chinensis Antoine, Picea koraiensis Nakai, and Cedrus deodara G. Don under near-natural conditions using the thermal-desorption cold trap gas chromatography/mass spectrometer technique. The effects of the VOCs on airborne microorganisms were investigated using the method of natural sedimentation. Results showed that the major VOCs were as follows: limonene, β-pinene, α-pinene,and α-caryophyllene in Pinus tabulaeformis and P. bungeana; limonene, borneol acetate, β-pinene, myrcene,and tricylene in S. chinensis; limonene, α-pinene, myrcene, camphene, and β-pinene in Picea koraiensis;and limonene, 2, (10)-pinene, α-pinene, and myrcene in C. deodara. These VOCs and the corresponding foliar extracts inhibited the growth of bacteria and stimulated the growth of fungi. Experimental data using monomers of the VOCs demonstrated that limonene, β-pinene, and three aldehydes could significantly inhibit bacterial growth, suggesting an inhibitory effect of VOCs on the growth of airborne microorganisms in the five conifer species. The bacteriostasis and air-decontaminating effects of plant VOCs are further discussed in terms of their chemical composition.     

Role of Ethylene in the Biosynthetic Pathways of Aroma Volatiles in Ripening Fruit

During the past decade, fruit aroma biosynthetic pathways were established in some climacteric fruits, such as tomato, apple, and melon. Inhibition of ethylene biosynthesis or its action in these fruits can reduce the production of fruit volatiles. Furthermore, ethylene partially regulates expression of a few important enzyme genes in fruit volatile biosynthetic pathways. The aim of this review is to bring together recent advances for understanding the regulatory role of ethylene in the biosynthesis of aroma volatiles in some fruits.     

Identification of attractant and repellent plants to coffee berry borer,Hypothenemus hampei

Colombia is one of the world's largest producers of coffee [Coffea arabica L. (Rubiaceae)]. The coffee berry borer (CBB), Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae), is the main pest of coffee. This insect is controlled through an integrated pest management program that includes cultural, biological, and chemical control strategies. Despite research seeking CBB attractants and repellents, these potential management tools have not been successfully incorporated into control programs. This work proposes the use of plant functional diversity for CBB management, for which a number of plants related to coffee and weeds were selected. CBB preference to these plants was determined by olfactometry and volatile compounds emitted by them were identified. Field trials were performed to test CBB preference under field conditions. These trials determined the olfactory preference of CBB to coffee berries accompanied by material of the plants Crotalaria micans Link (Fabaceae), Lantana camara L. (Verbenaceae), Nicotiana tabacum L. (Solanaceae), Artemisia vulgaris L., Calendula officinalis L., Stevia rebaudiana (Bertoni) Bertoni, and Emilia sonchifolia (L.) DC. (all four Asteraceae). Under laboratory conditions N. tabacum, L. camara, and C. officinalis were identified as repellents for CBB in olfactometer assays, whereas E. sonchifolia functioned as attractant. Controlled field trials corroborated CBB repellency of N. tabacum and L. camara; both release volatile sesquiterpenes. Selected candidate attractants included E. sonchifolia plants, for showing attraction in the laboratory. The potential use of these plants in agroecological management of coffee plantations is discussed.     

Net ecosystem fluxes and composition of biogenic volatile organic compounds over a maize field–interaction of meteorology and phenological stages

Bioenergy crop production is rapidly expanding in Europe, and the potential emissions of biogenic volatile organic compounds (BVOCs) might change the chemical composition of the atmosphere, influencing in turn air quality and regional climate. The environmental impacts of bioenergy crops on air chemistry are difficult to assess due to a lack of accurate field observations. Therefore, we studied BVOC fluxes from a bioenergy maize field in North‐Eastern Germany throughout the entire reproductive growth stage of the plants. Combining automated large chambers and proton transfer reaction mass spectrometry (PTR‐MS), we successfully measured fluxes of the highly reactive hydrocarbons monoterpenes (MTs) and sesquiterpenes (SQTs), together with several other BVOCs, including alcohols, aldehydes, ketones, benzenoids, and fatty acid derivatives. Emissions of MTs and SQTs were relatively high (17.0% and 3.6% of total mean molar BVOC emission, respectively) compared to methanol emissions (17.6%). Seasonal MT and SQT fluxes were clearly associated with the flowering phase, originating mainly from the flowering tissues as shown in additional laboratory experiments. From the observations of CO₂ net ecosystem exchange and evapotranspiration rates, we could exclude heat and drought stress‐induced BVOC emissions. Standard emission factors calculated for all compounds, chemical groups, and growth stages, showed that the temperature dependency of volatile terpenoid fluxes decreased distinctively with proceeding development stage. The results indicate that emissions from large‐scale bioenergy maize fields should be better differentiated and considered in regional estimates of aerosol formation. For the implementation of such relation into biogeochemical modelling, it should be considered that not only seasonal weather development but also phenological growth stages are determining the BVOC patterns and emission potentials.     

不同光质补光对促早栽培‘瑞都香玉’葡萄果实品质的影响

以4年生‘贝达’嫁接的早熟葡萄品种‘瑞都香玉’为试材,研究设施促早栽培条件下,紫外光、蓝光和红蓝光不同光质补光对果实品质的影响,结果表明: 促早栽培节能日光温室内环境属于典型的弱蓝紫光和弱紫外光环境.与对照(未补光)相比,夜间6 h的蓝光和紫外光补光处理可显著加快葡萄果实发育过程中质量和果粒纵横径的增大、果实糖含量的升高以及酸含量的下降,红蓝光效果不明显.果实成熟期紫外光补光处理果实的单粒质量最高,蓝光与红蓝光处理显著高于对照;蓝光补光处理果实葡萄糖、果糖和总糖含量最高,紫外光次之,红蓝光略高于对照.与对照相比,蓝光补光处理可显著加快果实中里那醇、α-萜品醇、橙花醇等萜烯类组分含量高峰的出现,而紫外光、红蓝光补光处理差异较小.果实成熟期蓝光补光处理果实中里那醇、香茅醇等萜烯类物质含量最高,紫外光补光处理里那醇含量较高,香叶醇、己醛、E-2-己烯醛等主要香气物质的含量最高,而红蓝光补光处理里那醇的含量与对照相比有所降低.紫外光、蓝光和红蓝光3种光质补光处理均增加了果实中醛酮类物质的种类及含量.表明蓝光补光处理果实发育最快,成熟最早,糖含量最高,里那醇等萜烯类物质含量高峰出现的时间最早;紫外光补光处理果实的单粒质量最大,主要萜烯类组分含量高;红蓝光补光处理对改善果实品质的效果不明显.     

狭叶红景天引种驯化后抗氧化能力、主要活性物质含量及挥发性组分的变化

以甘肃省甘南藏族自治州碌曲县栽培和野生狭叶红景天为材料,分别对根茎(主根和侧根)的抗氧化能力、可溶性糖、总黄酮、酚类和红景天苷含量,以及挥发性组分进行研究.结果表明: 狭叶红景天栽培根茎的自由基抑制率(I)、铁离子还原/氧化能力(FRAP),以及可溶性糖、总黄酮、酚类和红景天苷含量均显著大于野生根茎;栽培和野生根茎中均含有21种挥发性组分,相对含量较高的为苯乙酮、2-糠醛、棕榈酸等;与野生根茎相比,栽培根茎有15种组分的相对含量增加,主根中相对变化量较大的为3-羟基月桂酸、2,4-二叔丁基苯酚、亚麻酰氯等,侧根为2-乙酰呋喃、对羟苯基乙醇、丁子香酚等.栽培和野生侧根的I、FRAP值,以及总黄酮、酚类和红景天苷含量均显著大于主根.与主根相比,侧根有12种挥发性组分相对含量增加,变化量较大的为3-羟基月桂酸、10,13-十八碳二炔酸甲酯、对羟苯基乙醇等.栽培驯化后狭叶红景天根茎的抗氧化能力、主要活性物质含量及挥发性组分相对含量高于野生狭叶红景天,且侧根的品质更佳.     

不同颜色果袋对‘巨峰’葡萄果实中挥发性成分的影响

以‘巨峰’葡萄为试材,研究白袋、绿袋、红袋、蓝袋4种不同颜色果袋对葡萄成熟期果实中挥发性成分的影响,为葡萄专用果袋的研发提供理论依据.结果表明:不同颜色果袋可为葡萄果实的发育提供特定的光环境,不同套袋处理葡萄成熟期果实中的挥发性成分差异显著.‘巨峰’葡萄成熟期果实中检测到酯、醛、醇、酮类、萜烯类和芳香族化合物,对照、白袋、绿袋、红袋和蓝袋处理成熟期果实检测到的挥发性组分分别为33、37、38、32和34种.与对照相比,白袋处理乙酸乙酯、己酸乙酯等酯类物质含量降低,己醛、反式-2-己烯醛、癸醛含量增加;绿袋处理除3-己烯酸乙酯、反式-2-己烯酸乙酯、3-羟基丁酸乙酯、反式-2-己烯醛、(反,反)-2,4-己二烯醛、癸醛、苯乙醇外,其他共有组分的含量均出现降低;红袋处理乙酸乙酯、己酸乙酯等酯类物质含量降低,己醛、反式-2-己烯醛等的含量出现降低;蓝袋处理乙酸乙酯、己酸乙酯等主要酯类物质的含量未发生较大变化,己醛、反式-2-己烯醛等的含量出现升高.在非共有组分中,套袋处理中醇类组分的种类减少,萜烯类、芳香族化合物的种类增加.总体上,蓝袋处理果实中主要的‘果香型’酯类组分含量最高,白袋处理果实中主要的酯类组分及‘青草香型’的醛类组分含量较高,绿袋、红袋处理果实主要香气组分含量较低.     

不同酶对草鱼蛋白功能特性及风味成分的影响

通过蛋白酶对草鱼进行酶解,对其酶解产物的功能特性和酶解液的风味成分进行研究。结果显示,风味蛋白酶、胰蛋白酶酶解产物的溶解性、热稳定性均优于胃蛋白酶酶解产物(P0.05)。经酶处理后鱼肉酶解液鲜甜味氨基酸占比增加,苦味氨基酸占比减少;利用SPME-GC-MS共检测出83种挥发性成分,以醛酮类和醇类为主,酶解处理后醇类的相对含量显著减少,醛酮类的相对含量则显著增加,酶解液具有独特风味。经胰蛋白酶、风味蛋白酶酶解后的草鱼肉酶解产物及酶解液均可作为食品基料应用于加工中。     

Volatile organic compounds produced by Lysinibacillus sp. FJAT-4748 possess antifungal activity against Colletotrichum acutatum

FJAT-4748 is a bacterial strain isolated from forest soil samples taken from Dongba Valley, Lijiang, Kunming, Yunnan Province, PR China. This strain was identified as Lysinibacillus sp. based on a 16S rRNA gene sequence analysis. FJAT-4748 has been shown to possess antifungal activity against different fungi, including Colletotrichum acutatum, Aspergillus niger, Fusarium solani, Fusarium moniliforme and Fusarium oxysporum. The results of the present study indicate that this antifungal activity results from volatile organic compounds (VOCs) produced by this strain. The observed inhibition rates of VOCs from FJAT-4748 against these fungi were 100%, 100%, 37.20%, 18.94% and 7.64%, respectively. GC-MS analysis identified 24 VOCs from FJAT-4748, which included different categories of compounds, such as aldehydes, ketones, alcohols, aromatic hydrocarbons and alkanes. Of these 24 VOCs, the most abundant compound was 2-ethyl-1-hexanol, which constituted 36.24% of the total VOCs based on the relative peak area. In the in vitro C. acutatum mycelial growth assay, 2-ethyl-1-hexanol exhibited the strongest activity, with an inhibitory rate of 100% using 10?µL/plate of this VOC. The activity of benzaldehyde was lower. 2-decanone showed the weakest activity among the compounds tested. The inhibitory activity of an artificial mixture of three VOCs against the C. acutatum increased with the amount of artificial mixture used. The inhibition rate reached 100% using 30?µL/plate of this artificial mixture in the plate test. Taken together, these results show that the antifungal VOCs produced by Lysinibacillus sp. FJAT-4748 are potentially useful as agents for controlling anthracnose caused by Colletotrichum acutatum.