1,720,972 research outputs found
Chemical composition and bioactivities of essential oils from Pulicaria vulgaris subsp. dentata (Sm.) Batt. growing in Tunisia
No full textThe essential oils of the aerial parts and roots (APEO and REO) of Pulicaria vulgaris subsp. dentata (Sm.) Batt. were analyzed by GC and GC-MS. Twenty-one compounds (97.2% of the total oil composition) were identified in the REO, with γ-irone (39.2%), 7-epi-silphiperfol-5-ene (19.3%), 2,5-dimethoxy-p-cymene (8.5%) and γ-himachalene (8.0%) as main constituents. The APEO was rich in cis-β-guaiene (59.7%), together with eighteen other compounds, accounting for 93.2% of the total oil composition. Antiradical and enzymatic antioxidant properties of the isolated oils were also evaluated. The REO exhibited the highest antioxidant activity using DPPH, ABTS, catalase and paraoxonase tests. Antimicrobial, cytotoxic and tyrosinase inhibiting properties of these essential oils have been also studied. APEO exhibited significant activity towards Pseudomonas syringae and Agrobacterium tumefaciens. The REO showed the most significant cytotoxic effect against HeLa cell line and the highest tyrosinase inhibition activity
Assessment of Antioxidant and Antimicrobial Compounds of Volatiles from Leaves, Stems and Flowers of Olives
No full textProtection of olive cultivars, Olea europaea L., from diseases and the development of more sophisticated control methods are indispensable for a renovated and competitive olive sector. In this context, the volatiles obtained by the main Tunisian oil cultivar Chemlali and both the introduced cultivars Arbequina and Koroneiki were tested for their antimicrobial activity against several dangerous pathogens by diffusion and dilution methods (in 2014). To evaluate the adaptation to biotic stress, the antioxidant potential was additionally evaluated. The volatiles extracted from leaves, stems and flowers of the tested cultivars exhibited interesting antimicrobial and antioxidant activities, reaching in many cases 100% of inhibition. To identify the bioactive compounds, GC-FID and GC-MS were performed, permitting to identify up to 97.8% of total compounds. Both non-terpene hydrocarbons and terpenes were present in important proportions among volatiles
Abstracts book of the 13th Arab Congress of Plant Protection, Hammamet, Tunisia, 16-21 October 2022
No full textThis Publication is an Abstracts book of the 13th Arab Congress of Plant Protection (13th ACPP), organized by the Arab Society of Plant Protection (ASPP) in collaboration with the Ministry of Agriculture, Water Resources and Fisheries of Tunisia, represented by the National Institute of Agronomic Research of Tunisia (INRAT), held during the period 16-21 October 2022 in Hammamet, Tunisia.
The abstracts book contains 371 abstracts (Economic entomology, fungal diseases, bacterial diseases, viral diseases, phytoplasma, nematodes, weeds, chemical pesticides, plant extracts, IPM, biological control, climate change & plant protection, pest surveillance, soil-borne pathogens, food security & plant protection, and other) presented by scientists and graduate students from CWANA Countries, USA and Europe. In addition to the abstracts presented by scientists from the International Organizations such as the Food and Agriculture Organization of the United Nations (FAO), the International Center for Wheat and Maize (CIMMYT), the International Center for Agricultural Research in the Dry Areas (ICARDA), the International Centre for Advanced Mediterranean Agronomic Studies (CIHEAM), the European Plant Protection Organization (EPPO), The Mediterranean Phytopathological Union (MPU), the Arab Center for the Studies of Arid Zones and Dry Lands (ACSAD), the Arab Organization for Agricultural Development (AOAD), and the Islamic Organization for Food Security (IOFS).
The abstracts book was Edited by “Safaa G. Kumari, Khaled Makkouk, Mejda Daami-Remadi, Asma Najar, Hajer Ben Ghanem, Nader Asaad, Mohammad Kassem and Abdul Rahman Moukahel”; and published as a special issue of the Arab Journal of Plant Protection (AJPP), Volume 40, October 2022. 127 Pages (English) and 159 Pages (Arabic)
Effects Of Organic Substrates Nature On The Composting Process Parameters AndCompost Extract Efficiency On Soil-Borne Plant Diseases
Get PDFFour Composting windrows were carried out by the wastes (about 8 000 kg) in pyramidal form (height 1.5 m with base of 8m x 2 m) which constitute four different treatments: 1st treatment : 100% Cattle manure, 2nd treatment : 80% Cattle manure + 20% Sheep manure, 3rd treatment : 70% Cattle manure + 20% Sheep manure + 10% Poultry manure and 4th treatment : 50% Cattle manure + 20% Sheep manure + 20% Poultry manure+ 10% crushed wheat straw. Windrows were watered every time is necessary and turned over after 15 days. Temperature rased every two days and samples rased in every turned over. The physicochemical parameters of composting process revealed that the highest temperature of windrows was in thermophilic phase and has reached 66°C for T4 rich in carbon than for other treatments. The basic pH in the beginning decrease for all treatments and approachs the neutrality at the end of composting process, essentially for T1. A decrease of nitrogen percentage during composting probably due to a low level of C/N ratio in the beginning.The second part of this study starts in the maturity stage, a compost extract were prepared from different composts one volume of compost in 5 volume of water and 5 days of extraction period. The four obtained compost extracts, were experimented on different plants pathogens (Rhizoctonia solani, Fusarium solani, Fusarium oxysporum, Fusarium roseum, Fusarium graninearum and Phytophtora erythroseptica) in vivo and in vitro
Single and combined effects of Pythium oligandrum Po37 and a consortium of three rhizobacterial strains on Sclerotinia stem rot severity and tomato growth promotion
No full textInternational audienceIndividual plant growth-promoting rhizobacterial (PGPR) strains (Bacillus thuringiensis B2, Bacillus subtilis B10 and Enterobacter cloacae B16) and their combination were used, with or without Pythium oligandrum, against Sclerotinia sclerotiorum. In vitro, all biological control agents (BCAs) reduced successfully hyphal growth of the targeted pathogenic fungus. They displayed antifungal activity by more than 50% compared to controls. In planta trials were conducted two years in the row and led to a significant decrease in stem rot severity two months after the antagonist’s application onto infected tomato plants. The reduction reached 75% using rhizobacterial mixtures and 72% using P. oligandrum alone, compared to controls. The plant growth-promoting potential of the three-strain consortium and P. oligandrum was also assessed. Increased height in disease-free plants was obtained with rhizobacterial mixtures (60%) compared to P. oligandrum (47%). The BCA’s mixture increased the height of treated plants inoculated with S. sclerotiorum (up to 80%) compared to inoculated and untreated plants. The fresh weight of the aerial parts and roots of disease-free plants was increased by 42 and 30% over control following their treatment with mixtures of rhizobacteria and P. oligandrum alone, respectively. On plants inoculated with S. sclerotiorum in both trials, the highest growth-enhancing effect was achieved using the combined treatment based on P. oligandrum and the three-strain rhizobacterial consortium (Po37 + B2 + B10 + B16). The rhizospheric microbial communities were assessed using Single Strand Conformational Polymorphism (SSCP). Differences in the genetic structure of the fungal and bacterial communities were observed following treatments applied in both trials
Chemical composition and antifungal activity of Trigonella foenum-graecum L. varied with plant ploidy level and developmental stage
No full textAbstractThe efficacy of aerial parts’ organic extracts of diploid and mixoploid Trigonella foenum-graecum L. plants, harvested at three developmental stages (vegetative, flowering and fruiting) was evaluated for their antifungal activity against Fusarium oxysporum f. sp. radicis-lycopersici (FORL) and F. oxysporum f. sp. lycopersici (FOL). All tested extracts inhibited FORL and FOL mycelial growth. The organic extracts of diploid plants were found to be less toxic than mixoploid ones and this toxicity varied with the plant developmental stages. The diploids were most toxic, for the two strains, at the fruiting stage; however, mixoploids were more toxic at the vegetative stage for FOL and at flowering one for FORL. FOL was found to be more sensitive to fenugreek extracts when compared to FORL. LC–MS/MS analysis of methanolic extract of fenugreek aerial parts showed eleven different flavonol glycosides (quercetin, kaempferol and vitexin). Five novel components were identified, for the first time in fenugreek aerial parts, as kaempferol 3-O-β-d-glucopyranoside, kaempferol 7-O-glucoside, kaempferol 3-O-α-l-rhamnosyl (1→2) β-d-xyloside, kaempferol 7-O-β-d-glucopyranosyl (1–4) β-d-glucopyranoside and kaempferol 3-O-β-glucosyl (1→2) (6′-O-acetyl)-β-d-galactoside, along with other known compounds of this species. To operate with the maximum efficiency, the allelopathic potential of a given plant, our study showed that it would be advisable to identify the most productive developmental stage of allelochemicals. Similarly, it seems that mixoploidy would be a simple and effective biotechnology tool to improve (in quantity and quality) the allelochemicals’ production, since the extracts’ toxicity of diploid and mixoploid plants, was different
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
CHEMICAL COMPOSITION AND BIOLOGICAL ACTIVITIES ASSESS-MENT OF OLIVE FRUIT VOLATILES FROM DIFFERENT VARIETIES GROWN IN TUNISIA
Get PDFVolatile compounds, present in olives, are responsible for the olive fruit flavor and oil aroma, influencing the consumer’s preference. These compounds have a biological activity to fight off pathogens. The aim of this work is to characterize volatiles in pulps and cores of Chemlali, Arbequina and Koroneiki olives, collected from Menzel Mhiri-Kairouan, and to test both the efficiency of these compounds against two bacteria and six phytopathogenic fungal species, by diffusion and dilution methods, and their antioxidants activities. The analyzis of volatiles were determined by GC-FID and GC-MS in three cultivars at the full ripening stage. Thirty five compounds were identified, such us an assortment of phenol, alcohol, hydrocarbon, aldehyde and terpenes derivatives. A high changes in volatiles was noted between cultivars and fruit organs. In fact, the major compounds in the pulps and the cores, of different cultivars, are (E)-2-decenal (46.9%), nonanal (19.6%), 1-hexadecene (16.3%), 7-Methyl-1,3,5-cycloheptatriene 7-Methyl-1,3,5-Cycloheptatriene (15.47%), (E,E)-2,4-decadienal (14.5%) and 1-tetradecene (14.6%). Also, the cores volatiles illustrated more richness in aldehydes than the pulps for all cultivars. Volatile fractions exhibited a moderate to important antibacterial activities against bacteria. However, Arbequina cores volatiles and both Chemlali and Koroneiki pulps volatiles established a moderate to higher activities against tested fungi. The DPPH and ABTS•+ tests demonstrated that the highest antioxidant capacity of volatiles were assigned to Arbequina cores and Koroneiki pulps. The Principal Components Analysis showed a significant relationship between antioxidants and/or antimicrobial properties and the levels of the main volatile compounds (limonene, methyldecane, nonanal, E-2-decenal, camphor, geranic acid, tetradecene, hexadecane, tetradecane) in different fruit organs.Volatile compounds, present in olives, are responsible for the olive fruit flavor and oil aroma, influencing the consumer’s preference. These compounds have a biological activity to fight off pathogens. The aim of this work is to characterize volatiles in pulps and cores of Chemlali, Arbequina and Koroneiki olives, collected from Menzel Mhiri-Kairouan, and to test both the efficiency of these compounds against two bacteria and six phytopathogenic fungal species, by diffusion and dilution methods, and their antioxidants activities. The analyzis of volatiles were determined by GC-FID and GC-MS in three cultivars at the full ripening stage. Thirty five compounds were identified, such us an assortment of phenol, alcohol, hydrocarbon, aldehyde and terpenes derivatives. A high changes in volatiles was noted between cultivars and fruit organs. In fact, the major compounds in the pulps and the cores, of different cultivars, are (E)-2-decenal (46.9%), nonanal (19.6%), 1-hexadecene (16.3%), 7-Methyl-1,3,5-cycloheptatriene 7-Methyl-1,3,5-Cycloheptatriene (15.47%), (E,E)-2,4-decadienal (14.5%) and 1-tetradecene (14.6%). Also, the cores volatiles illustrated more richness in aldehydes than the pulps for all cultivars. Volatile fractions exhibited a moderate to important antibacterial activities against bacteria. However, Arbequina cores volatiles and both Chemlali and Koroneiki pulps volatiles established a moderate to higher activities against tested fungi. The DPPH and ABTS•+ tests demonstrated that the highest antioxidant capacity of volatiles were assigned to Arbequina cores and Koroneiki pulps. The Principal Components Analysis showed a significant relationship between antioxidants and/or antimicrobial properties and the levels of the main volatile compounds (limonene, methyldecane, nonanal, E-2-decenal, camphor, geranic acid, tetradecene, hexadecane, tetradecane) in different fruit organs
Combining potential oomycete and bacterial biocontrol agents as a tool to fight tomato Rhizoctonia root rot
No full textBiological control of Rhizoctonia root rot and growth-promoting potential on two tomato cultivars was performed using Pythium oligandrum in combination, or not, with three tomato-associated rhizobacterial strains of Bacillus subtilis, B. thuringiensis and Enterobacter cloacae. The three bacterial strains displayed antifungal activity against Rhizoctonia solani, with pathogen growth inhibition up to 60%. P. oligandrum also destroyed R. solani cells by antibiosis and mycoparasitism processes. In a three-month greenhouse assays, for all trials and the two tomato cultivars used, disease suppression potential, as compared to the controls, was up to 80% using the microorganisms mixtures and 74% by using P. oligandrum alone. Increased height in disease-free plants was obtained with the microorganism mixtures (59%) compared to P. oligandrum (49%). Plants grown in R. solani inoculated peat and challenged with microorganism mixtures were higher than controls, whereas those amended with P. oligandrum showed 46 to 87% height increase. All treatments with the microorganisms were more effective in suppressing the disease than chemical fungicide. Increment of aerial parts and root fresh weights on disease-free plants were until 51% for those treated with microorganism mixtures compared to 46% recorded using P. oligandrum. On inoculated plants, these parameters were enhanced using the mixed treatment. No differences in the rhizosphere-bacterial populations were observed by Single Strand Conformational Polymorphism (SSCP) when, either the rhizobacteria, with or without P. oligandrum, or the pathogen, were inoculated. This suggests that the native bacterial communities were not significantly impact
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