Bruno Campanella

Presence, in the rhizosphere and leaf extracts of zucchini (Cucurbita pepo L.) and melon (Cucumis melo L.), of molecules capable of increasing the apparent aqueous solubility of hydrophobic pollutants.

ABSTRACT In the wake of the observation made by Hülster and Neumann that zucchini absorbs large quantities of dioxins and furans through its roots, our research is aimed at contributing to the description of the mechanism involved. According to the current hypothesis, a molecule produced by the plant and released into its root exudates binds to the pollutant. These complexes are more hydrophilic than the pollutant itself. These are more mobile in the soil solution, are absorbed by the roots, and translocated into all plant parts. We first attempted to isolate a molecule that is capable of binding 2,3,7,8-TCDD in Cucurbita pepo L., Cucurbita maxima Duchesne ex Poiret, Cucumis sativus L., Cucumis melo L., Daucus carota L. and Lycopersicon esculentum L. These trials showed that such a molecule is present in the tissues and the rhizosphere of melon. Therefore, we focused our research on this species, using zucchini as a reference. Later tests on solubility and precipitation characteristics showed that the binding molecules found in both species had identical properties in many respects. It appears that zucchini and melon contain several binding molecules, and results suggest that at least one of these would be of a proteinic nature. A fundamental study of the binding substance could lead to applications in the fields of soil remediation by phytoextraction.

A multiple-level study of metal tolerance in Salix fragilis and Salix aurita clones

UNLABELLED The response of two willow clones (Salix fragilis (Sf) and Salix aurita (Sa)) to the presence of metals (Zn, Cu, Cd, Ni) was studied. Rooted cuttings were planted in control and contaminated soil. After 100days, different parameters (biomass, chlorophyll fluorescence (Fv/Fm), pigment and sugar concentrations, electrolyte leakage and proteome-level changes) were analyzed. The growth of Sa was not influenced by metals whereas Sf produced significantly less biomass when exposed to the pollutants. Furthermore, although Sa did not show a growth reduction in the presence of metals, the overall view of the physiological results among others the changes in the accumulation of sugars and pigments indicated that metals had a more severe impact on this clone. The response at the proteome level confirmed these observations. The growth reduction and the proteomic changes in Sf indicate that this clone adjusts its metabolism to maintain cellular homeostasis. Sa on the contrary maintains growth but the physiological and proteomics data suggests that this can only be done at the cost of cellular deregulation. Therefore high biomass is not linked with a good tolerance strategy. In a long-term study the survival of Sa might be compromised making it a poorer candidate for phytoremediation efforts. BIOLOGICAL SIGNIFICANCE In the last centuries human activity has resulted in the dispersal of heavy metals with potential phytotoxic effects over large areas. The increased knowledge of the responses of Salix-species, a group of trees with potential as biomass producer but also as phytoremediation agent, when growing on metal-polluted substrate provided by this study has the potential to help in the improved selection of clones with more or less potential for these aims. Contrary to most studies the trees in the current study were exposed to a mixture of metals, thereby facing a closer resemblance to the situation on soils polluted by human activity. Whereas many papers focused on the two main phenotypic characteristics (biomass and accumulation), fewer papers studied proteomic and physiological parameters which allow to have a global view of the tolerance of probable willow candidates for phytoremediation purposes. Our data demonstrates that higher biomass production in presence of metals is not necessarily linked with higher tolerance whereas growth reduction might indicate longer long-term tolerance. In the long term and in the purpose of a future use in phytoremediation, the survival of this high producer clone could be compromised.

Physiological and Proteomic Responses of Different Willow Clones (Salix fragilis X alba) Exposed to Dredged Sediment Contaminated by Heavy Metals

High biomass producing species are considered as tools for remediation of contaminated soils. Willows (Salix spp.) are prominent study subjects in this regard. In this study, different willow clones (Salix fragilis x alba) were planted on heavy-metal polluted dredging sludge. A first objective was assessment of the biomass production for these clones. Using a Gupta statistic, four clones were identified as high biomass producers (HBP). For comparison, a group of four clones with lowest biomass production were selected (LBP). A second objective was to compare metal uptake as well as the physiological and proteomic responses of these two groups. All these complementary datas allow us to have a better picture of the health of the clones that would be used in phytoremediation programs. Cd, Zn, and Ni total uptake was higher in the HBPs but Pb total uptake was higher in LBPs. Our proteomic and physiological results showed that the LBPs were able to maintain cellular activity as much as the HBPs although the oxidative stress response was more pronounced in the LBPs. This could be due to the high Pb content found in this group although a combined effect of the other metals cannot be excluded.

Données ethnobotaniques, pharmacologiques et agro-industrielles sur une plante prometteuse : le kénaf ( Hibiscus cannabinus L.)

RésuméLe kénaf (Hibiscus cannabinus L.) est une plante annuelle, appartenant à la famille des Malvacées, appelée aussi chanvre de Deccan. Le kénaf est connu pour ses vertus médicinales très intéressantes vu les activités pharmacologiques des composées phytochimiques présentes dans les extraits de la plante. Actuellement, le kénaf est surtout cultivé en Inde, au Pakistan et en Thaïlande. En Europe, la culture existe en France, en Italie, en Espagne et en Suisse. Cette plante fait l’objet de plusieurs recherches où on la considère, en plus de ses vertus médicinales, comme une source prometteuse de fibres utilisées pour la fabrication de pâte à papier et dans des secteurs traditionnels tels que le textile, le cordage et l’alimentation du bétail. Récemment, les fibres ont été utilisées dans des nouveaux secteurs tels que la construction, l’isolation et l’automobile.AbstractKenaf (Hibiscus cannabinus L.) is an annual plant, belonging to Malvaceae family, also known as deccan hemp. Kenaf is known for its interesting medicinal uses resulting from the pharmacological activities of phytochemicals compound of the plant extracts. Kenaf is grown mainly in India, Pakistan and Thailand. In Europe, the culture exists in France, Italy, Spain and Switzerland. It is the subject of research and considered, in addition to its medicinal virtues, as a promising fibre source for making paper pulp and used in traditional sectors such as textiles, rope making and feed. Recently, they were used in new sectors such as construction, insulation and automobile.

Bioaccumulation and Photosynthetic Activity Response of Kenaf ( Hibicus cannabinus L. ) to Cadmium and Zinc

The response of kenaf ( Hibiscus cannabinus L.) to Zn/Cd contamination in soil was investigated using pot experiment. Plants were grown on soils containing increasing doses of two metals. Zn and Cd were applied alone or combined. Growth parameters as well as content of photosynthetic pigments, and photosynthetic performance were determined. Soil and plant tissue were analyzed by atomic absorption spectrometry. Metal concentration in plants increased when metal dose in soil increased. The Zn and Cd concentrations were analyzed in order of root >leaf>stem. The Zn-Cd interaction reduced the Cd concentration in plants and alleviates the toxicity of Cd on photosynthetic system, and showed that Cd and Zn acted synergistically to Cd accumulation in plants. The reduction of photosynthetic activity observed did not correlate with the changes in the biomass production. Hibiscus cannabinus L. could be an accumulator candidate of Cd and Zn contaminated sites.