63 research outputs found
Ecophysiological studies of two andean forest contrasting species Abatia parviflora and Myrcianthes leucoxyla under Bogotá conditions, Colombia
Bark anatomy, chemical composition and ethanol-water extract composition of Anadenanthera peregrina and Anadenanthera colubrina
The bark of Anadenanthera peregrina (L.) Speg and Anadenanthera colubrina (Vell.) Brenan
were characterized in relation to anatomical and chemical features. The barks were
similar and included a thin conducting phloem, a largely dilated and sclerified non-conducting
phloem, and a rhyridome with periderms with thin phellem interspersed by cortical tissues.
Only small differences between species were observed that cannot be used alone for
taxonomic purposes. The summative chemical composition of A. peregrina and A. colubrina
was respectively: 8.2% and 7.7% ash; 28.8% and 29.3% extractives; 2.4% and 2.6%
suberin; and 18.9% lignin. The monosaccharide composition showed the predominance of
glucose (on average 82% of total neutral sugars) and of xylose (9%). The ethanol-water
extracts of A. peregrina and A. colubrina barks included a high content of phenolics, respectively:
total phenolics 583 and 682 mg GAE/g extract; 148 and 445 mg CE/g extract; tannins
587 and 98 mg CE/g extract. The antioxidant activity was 238 and 269 mg Trolox/g extract.
The barks of the Anadenanthera species are a potential source of polar extractives that will
represent an important valorization and therefore contribute to improve the overall economic
potential and sustainability of A. peregrina and A. colubrinainfo:eu-repo/semantics/publishedVersio
Separation of Allelopathy from Resource Competition Using Rice/Barnyardgrass Mixed-Cultures
Plant-plant interference is the combined effect of allelopathy, resource competition, and many other factors. Separating allelopathy from resource competition is almost impossible in natural systems but it is important to evaluate the relative contribution of each of the two mechanisms on plant interference. Research on allelopathy in natural and cultivated plant communities has been hindered in the absence of a reliable method that can separate allelopathic effect from resource competition. In this paper, the interactions between allelopathic rice accession PI312777, non-allelopathic rice accession Lemont and barnyardgrass were explored respectively by using a target (rice)-neighbor (barnyardgrass) mixed-culture in hydroponic system. The relative competitive intensity (RCI), the relative neighbor effect (RNE) and the competitive ratio (CR) were used to quantify the intensity of competition between each of the two different potentially allelopathic rice accessions and barnyardgrass. Use of hydroponic culture system enabled us to exclude any uncontrolled factors that might operate in the soil and we were able to separate allelopathy from resource competition between each rice accession and barnyardgrass. The RCI and RNE values showed that the plant-plant interaction was positive (facilitation) for PI312777 but that was negative (competition) for Lemont and barnyardgrass in rice/barnyardgrass mixed-cultures. The CR values showed that one PI312777 plant was more competitive than 2 barnyardgrass plants. The allelopathic effects of PI312777 were much more intense than the resource competition in rice/barnyardgrass mixed cultures. The reverse was true for Lemont. These results demonstrate that the allelopathic effect of PI312777 was predominant in rice/barnyardgrass mixed-cultures. The most significant result of our study is the discovery of an experimental design, target-neighbor mixed-culture in combination with competition indices, can successfully separate allelopathic effects from competition
Seasonal variation in allelopathic potential of the leaves of Copaifera langsdorffii Desf.
Age- and environment-dependent changes in chemical defences of larval and post-metamorphic toads
Allelopathic Inhibition by Scenedesmus obliquus of Photosynthesis and Growth of Microcystis aeruginosa
Corrigendum to “Benzoxazinoids in wheat allelopathy – From discovery to application for sustainable weed management” [Environ. Exp. Bot. 202 (2022) 104997/EEB_104997]
Benzoxazinoids in wheat allelopathy – From discovery to application for sustainable weed management
Ecologically Acceptable usage of Derivatives of Essential Oil of Sweet Basil, Ocimum basilicum,
Ethanol solutions of five fractions obtained from essential oil of sweet basil Ocimum basilicum L. (Lamiales: Lamiaceae) (F1–F5) were tested for their antifeedant properties against 2(nd) instar gypsy moth larvae, Lymantria dispar L. (Lepidoptera: Lymantriidae), in laboratory non-choice and feeding-choice experiments. Prior to bioassays, the chemical composition of each fraction was determined by gas chromatography analyses. Significant larval deterrence from feeding was achieved by application of tested solutions to fresh leaves of the host plant. The most effective were were F1 (0.5%), F4 (0.05, 0.1, and 0.5%), and F5 (0.1 and 0.5%), which provided an antifeedant index > 80% after five days. A low rate of larval mortality was observed in no-choice bioassay. In situ screening of chlorophyll fluorescence as an indicator of plant stress level (assessed by the induced fluorometry) confirmed that the tested compounds did not cause alternations in the photosynthetic efficiency of treated leaves
Comparison Study of Allelochemicals and Bispyribac-Sodium on the Germination and Growth Response of Echinochloa crus-galli L.
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