7,409 research outputs found

    Glucosinolate hydrolysis compounds for weed control

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    Glucosinolates are allelochemicals present in all Brassica plants. Upon hydrolysis by endogenous enzymes they produce a series of biologically active compounds, such as isothiocyanates and their deriva-tives among others. These compounds have marked fungicidal, nematocidal and herbicidal effects and therefore their use as biodegradable natural products for crop protection has attracted much attention in the last years. A number of these compounds, either individually or in combination, were tested against Sinapis alba and Lollium perenne in Petri dishes bio-assays. C50 values as low as 0.7 and 0.2 mM were obtained. This may open the possibility for using glucosinolate hydrolysis products as herbicides

    Glucosinolate hydrolysis products for weed control

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    Glucosinolates are allelochemicals present in all Brassica plants. Upon hydrolysis by endogenous enzymes they produce a series of biologically active compounds, such as isothiocyanates and their deriva-tives among others. These compounds have marked fungicidal, nematocidal and herbicidal effects and therefore their use as biodegradable natural products for crop protection has attracted much attention in the last years. A number of these compounds, either individually or in combination, were tested against Sinapis alba and Lollium perenne in Petri dishes bio-assays. C50 values as low as 0.7 and 0.2 mM were obtained. This may open the possibility for using glucosinolate hydrolysis products as herbicides

    The effects of leaching from alkaline red mud on soil biota: modelling the conditions after the Hungarian red mud disaster

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    A soil column experiment was set up to investigate the effect of red mud from Ajka (Hungary) on a typical soil profile from the concerned area. The chemical changes caused by the leachate of the red mud and the effects of these changes on living organisms were assessed. Ecotoxicological tests with Vibrio fischeri, Sinapis alba and Folsomia candida were performed and the number of aerobic heterotrophic microorganisms was determined. The total, plant available, exchangeable and water soluble fractions of Na, Mo, Cu, and Cr increased in the soil mostly due to their leaching from the red mud layer and partly to the increase of the pH and DOC concentration. The chemical changes had significant effects on the test organisms only in the 0 – 30 cm soil layer except for F. candida that had a lower survival rate also in the 30 – 50 cm soil layer. There were no severe toxic effects detected on the test organisms. Furthermore in case of the aerobic heterotrophic cell number and S. alba germination a stimulating effect was revealed. However, the red mud itself was toxic, therefore the performed ecotoxicology tests have justified the removal of red mud from the soil surface after the disaster

    Хімічний склад насіння та вегетативної маси гірчиці залежно від погодних умов періоду вегетації

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    The difference between Brassica juncea and Sinapis alba as for their chemical contents of seeds, vegetative mass and oil has been found out. The seeds of  Brassica juncea contain more oil than Sinapis alba (approximately 42,08 as compared with 37,87) while the latter has more protein (27,70 as compared to 23,11). Oleic acid prevails in Brassica juncea oil (46,68%) while erucic (C22:1) does in Sinapis alba (44,0%). Brassica juncea accumulates higher yield of dry seed matter as compared to Sinapis alba, while the latter has a richer vegetative mass. Brassica juncea spends less nitrogen and potassium but more phosphorus for producing 1 centner of dry seed matter as compared to Sinapis albaОбнаружено различия между горчицей сизой (Brassica juncea) сорт Тавричанка 5 и горчицей белой (Sinapis alba) сорт Талисман по химическому составу семян, вегетативной массы и жира. В семенах горчицы сизой больше жира, чем у белой (соответственно 42,08 и 31,87), в горчице белой – больше белка, чем у сизой (27,70 и 23,11). В масле горчицы сизой преобладает олеиновая кислота (в среднем 46,68%), горчицы белой – эруковая (44%). Горчица сизая в сравнении с белой накапливает более высокий урожай сухого вещества семян, горчица белая – вегетативной массы. Горчица сизая на создание 1 ц сухого вещества использует азота и калия меньше, а фосфора – больше, чем горчица белаяВиявлено розбіжності між гірчицею сизою (Brassica juncea) сорту Тавричанка 5 і гірчицею білою (Sinapis alba) сорту Талісман за хімічним складом насіння, вегетативної маси та олії. У насінні гірчиці сизої більше олії, ніж у білої (у середньому 42,08 проти 31,87); у гірчиці білої – більше білка, ніж у сизої (27,70 проти 23,11). В олії гірчиці сизої переважає олеїнова кислота (у середньому 46,68%), гірчиці білої – ерукова (44,0%). Гірчиця сиза у порівнянні з білою накопичує більший урожай сухої речовини насіння, гірчиця біла – більше вегетативної маси. Гірчиця сиза на створення 1 ц сухої речовини витрачає азоту й калію менше, а фосфору – більше, ніж біл

    Screening von Senf-Genotypen zur Körnernutzung im ökologischen Anbau in Mitteleuropa

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    Information is rare about mustard (Sinapis alba, Brassica nigra, B. juncea) varieties and their characteristics for a suitable performance under organic conditions. 30 accessions were grown at the organic Research Station Kleinhohenheim in SW Germany in the year 2011. Highest grain yield was obtained by S. alba (10.5 g/plant) which was about four times the yield of B. nigra, and ten times the yield of B. juncea, mainly because of higher thousand kernel mass and high number of pods. B nigra and B. juncea were heavily damaged by pests so that only S. alba seems a suitable mustard species for German organic farming at the moment

    Post-harvest sown catch crops – results from two years of organic field trials

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    Post-harvest sown catch crops should be sown as early as possible in order to obtain maximum biomass and nutrient uptake in the harvested crop, as biomass production decreased by 2-3.5 percent per day, when time of sowing was postponed throughout August. Furthermore, the winter hardy species included in these experiments had a tendency to yield less than the non-winter hardy catch crops. These experiments imply that early sown catch crops may become a biomass supplement for organic biogas production, provided sufficient yields are obtained and costs for harvest, transportation and storage are adequately low

    Using an oilseed rape x wild/weedy relative gene flow index for the monitoring of transgenic oilseed rape

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    To estimate the introgressive hybridisation propensity (IHP) between transgenic oilseed rape and certain of its cross-compatible wild/weedy relatives at the landscape level, a conceptual approach was developed. A questionnaire was established enclosing the successive steps to successfully achieve introgressive hybridisation. Each step was described and scored, resulting in an IHP value for each cross-compatible wild/weedy relative. This approach revealed that in Flanders (Belgium) Brassica rapa has the highest IHP value, followed by Hirschfeldia incana, Diplotaxis tenuifolia, Raphanus raphanistrum and Sinapis arvensis. Using these values, monitoring priorities can be defined within the pool of cross-compatible wild/weedy oilseed rape relatives. It is discussed how the numerical quantification may serve as a valuable tool in case-specific monitoring and general surveillance of transgenic oilseed rape

    Concentration- and time-dependent effects of isothiocyanates produced from Brassicaceae shoot tissues on the pea root rot pathogen Aphanomyces euteiches

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    Isothiocyanates (ITCs) hydrolyzed from glocosinolates (GSLs) in Brassicaceae tissue are toxic to soil organisms. In this study, the effect of aliphatic and aromatic ITCs from hydrated dy Brassicaceae shoot tissues on the mycelium and oospores of the pea root rot pathogen Aphanomyces euteiches was investigated. The profile and concentrations of GSLs in two test Brassicaceae species, Sinapis alba and Brassica juncea, and the ITCs from the dominant hydrolyzed parent GSLs were monitored. The concentrations of dominant ITCs and pathogen exposure time were evaluated in in vitro experiments. The greatest effect on the pathogen was observed from aliphatic ITCs hydrolyzed from B. juncea tissue, and the effect depended on the ITS concentration and exopsure time. ITCs were more effectively hydrolyzed from B. juncea GSLs than from S. alba GSLs; i.e., the ITC/GSL ratio was higher in B. juncea than in S. albatissue, giving a different release pattern. The release of phenylethyl isothiocyanate, which was common to both species, followed a pattern similar to that of the dominant ITC in each crop speices. This suggests that trait other than GSL content, e.g., plant cell structure, may affect the release of ITCs ans should therefore influence the choice of speices used for biofumigation purposes

    Aphids associated with shrubs, herbaceous plants and crops in the Maltese Archipelago (Hemiptera, Aphidoidea)

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    A survey of the aphids associated with Maltese shrubs, herbaceous plants and crops was carried out. Sixty six aphid species were recorded from more than 90 species of host plants. Forty eight aphids were recorded from the Maltese islands for the fi rst time bringing the total number of aphid species known from these islands to 99. New records include: Acyrthosiphon lactucae, A. pisum, Anoecia vagans, Aphis alienus, A. euphorbiae, A. hederae, A. lambersi, A. multifl orae, A. nasturtii, A. parietariae, A. picridicola, A. ruborum, A. sedi, Aulacorthum solani, Brachycaudus helichrysi, Capitophorus sp. nr. similis, Clypeoaphis suaedae, Cryptomyzus korschelti, Dysaphis apiifolia, D. foeniculus, D. pyri, D. tulipae, Hyadaphis coriandri, H. foeniculi, H. passerinii, Hyperomyzus lactucae, Idiopterus nephrelepidis, Macrosiphoniella absinthii, M. artemisiae, M. sanborni, Macrosiphum euphorbiae, Ma. rosae, Melanaphis donacis, Metopolophium dirhodum, Pterochloroides persicae, Rectinasus buxtoni, Rhopalosiphum maidis, R. padi, R. rufi abdominale, Schizaphis graminum, Semiaphis dauci, Sipha maydis, Sitobion avenae, S. fragariae, Therioaphis alatina, Uroleucon inulae, U. hypochoeridis and U. sonchi. Of these 99 aphid species, 58 are of economic importance and 16 are alien introductions. For 15 of the aphid species, a total of 22 new host-plant records are made. Ten species of ants were found attending 18 aphid species.peer-reviewe
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