What about transfers and effects of edaphic pollutants on the restoration of peatlands ? Comment pouvons-nous intégrer les transferts et effets de polluants organiques d’origine édaphiques dans la restauration de tourbières ?

National audienc

Carbon Radiochemicals (14C) and Stable Isotopes (13C): Crucial Tools to Study Plant-Soil Interactions in Ecosystems

International audienc

Physiological and biochemical parameters: new tools to screen barley root exudates allelopathic potential (*Hordeum vulgare* L. subsp. *vulgare*

peer reviewedMorphological markers/traits are often used in the detection of allelopathic stress, but optical signals including chlorophyll a fluorescence emission could be useful in developing new screening techniques. In this context, the allelopathic effect of barley (Hordeum vulgare subsp. vulgare) root exudates (three modern varieties and three landraces) were assessed on the morphological (root and shoot length, biomass accumulation), physiological (Fv/Fm and F0), and biochemical (chlorophyll and protein contents) variables of great brome (Bromus diandrus Roth., syn. Bromus rigidus Roth. subsp. gussonii Parl.). All the measured traits were affected when great brome was grown in a soil substrate in which barley plants had previously developed for 30 days before being removed. The response of receiver plants was affected by treatment with activated charcoal, dependent on barley genotype and on the nature of the growing substrate. The inhibitory effect was lower with the addition of the activated charcoal suggesting the release of putative allelochemicals from barley roots into the soil. The barley landraces were more toxic than modern varieties and their effect was more pronounced in sandy substrate than in silty clay sand substrate. In our investigation, the chlorophyll content and Fv/Fm were the most correlated variables with barley allelopathic potential. These two parameters might be considered as effective tools to quantify susceptibility to allelochemical inhibitors in higher plants

Potencial alelopático de Cyperus rotundus L. sobre espécies cultivadas Allelopathic potential of Cyperus rotundus L. upon cultivated species

Metabótitos secundários produzidos em algumas plantas podem provocar alterações no desenvolvimento de outras plantas ou até mesmo de outros organismos. Neste trabalho, objetivou-se identificar possíveis efeitos alelopáticos de extratos aquosos de folhas de Cyperus rotundus na germinação e no crescimento de plântulas de Brassica campestris, Brassica oleracea var. botrytis, Brassica oleracea var. capitata, Brassica oleracea var. italica, Brassica rapa, Lactuca sativa cv. Grand rapids, Lycopersicum esculentum e Raphanus sativus. Foram utilizadas sete concentrações do extrato aquoso (0, 10, 30, 50, 70, 90 e 100%). Os tratamentos foram arranjados em delineamento inteiramente casualizado, com cinco repetições de dez sementes das espécies cultivadas, constituindo a unidade amostral. Os extratos aquosos de C. rotundus evidenciaram potencialidades alelopáticas na germinação das sementes e no crescimento das duas partes vegetais (raiz e parte aérea), de todas as espécies testadas, exceto na germinação de sementes de tomate e de alface, sendo que a redução aumentou com o aumento das concentrações dos extratos aquosos utilizados. A estrutura vegetal mais afetada em presença dos extratos aquosos foi o sistema radicular das plântulas.<br>Secondary metabolites produced in some plant species may promote changes in the development of other plants or even in other organisms. The aim of this work was to identify the possible allelopathic effects of aqueous extracts of Cyperus rotundus leaves on germination and growth of Brassica campestris, Brassica oleracea var. botrytis, Brassica oleracea var. capitata, Brassica oleracea var. italica, Brassica rapa, Lactuca sativa cv. Grand rapids, Lycopersicum esculentum and Raphanus sativus seedlings. Seven aqueous extract concentrations were used (0, 10, 30, 50, 70, 90, and 100%). The treatments were arranged in a completely randomized desing, with five replications of ten seeds of each cultivated species constituting the sample unity. The aqueous extracts of C. rotundus revealed allelopathic potentialities on germination of seeds and growth of two vegetable parts (root and aerial part) of all tested species, except on germination of L. sativa and L. esculentum seeds, being that the reduction increased with the increase of the aqueous concentration extracts which were used. The seedlings roots were the most affected structure in the presence of aqueous extracts