The accumulation of metals, PAHs and alkyl PAHs in the roots of Echinacea purpurea.

We examined the accumulation of polycyclic aromatic hydrocarbons (PAHs), alkyl PAHs, and toxic metals in soils by the roots of Echinacea purpurea (L.) Moench, in a 20-week greenhouse study and a 2-year field study. In the greenhouse study, inoculation by arbuscular mycorrhizal fungus (AMF), Rhizoglomus intraradices (N.

Preventable obstetrical interventions: how many caesarean sections can be prevented in Canada?

Public health authorities have been alarmed by the progressive rise in rates of Caesarean section in Canada, approaching one birth in three in several provinces. We aimed therefore to consider what were preventable obstetrical interventions in women with a low-risk pregnancy and to propose an analytic framework for the reduction of the rate of CS. We obtained statistical variations of CS rates over time, across regions, and within professional practices from MED-ÉCHO, the Quebec hospitalization database, from 1969 to 2009.

Some like it toxic.

Humans are notorious for disturbing terrestrial ecosystems worldwide, especially those that are in close proximity to urban areas. This disturbance has involved the accumulation of various types of chemical pollutants, of either agricultural or industrial origins, in both soil and water ecosystems. Pollutants have sometimes included essential plant nutrients, such as phosphate and nitrate, which have piled up throughout the years in many ecosystems as a consequence of aggressive agricultural practices, and a number of toxic or trace metals, e.

Nickel remediation by AM-colonized sunflower.

This greenhouse study aimed to examine the contribution of arbuscular mycorrhizal (AM) colonization on the uptake of and tolerance to nickel (Ni) in sunflower (Helianthus annuus L.). We hypothesized that AM colonization increases Ni content and tolerance in sunflower grown under varying soil Ni concentrations.

Root colonization by an arbuscular mycorrhizal (AM) fungus increases growth and secondary metabolism of purple coneflower, Echinacea purpurea (L.) Moench.

Purple coneflower, Echinacea purpurea (L.) Moench, is an important phytomedicinal species that contains phenolics and alkamides with antipathogenic properties. This study aimed to examine the effect of arbuscular mycorrhizal (AM) colonization on the physiology and biochemistry of E.

Allocation plasticity and plant-metal partitioning: meta-analytical perspectives in phytoremediation.

In this meta-analysis of plant growth and metal uptake parameters, we selected 19 studies of heavy metal (HM) phytoremediation to evaluate trends of allocation plasticity and plant-metal partitioning in roots relative to shoots. We calculated indexes of biomass allocation and metal distribution for numerous metals and plant species among four families of interest for phytoremediation purposes (e.g.

Dynamics of arbuscular mycorrhizal symbiosis in heavy metal phytoremediation: meta-analytical and conceptual perspectives.

To estimate dynamics of arbuscular mycorrhizal (AM) symbiosis in heavy metal (HM) phytoremediation, we conducted a literature survey and correlated HM uptake and relative plant growth parameters from published data. After estimating AM feedback responses for these parameters at low and high soil-HM concentration intervals, we determined that the roles of AM symbiosis are characterized by (1) an increased HM phytoextraction via mycorrhizospheric 'Enhanced Uptake' at low soil-HM concentrations, and (2) a reduced HM bioavailability via AM fungal 'Metal-Binding' processes at high soil-HM levels, hence resulting in increased plant biomass and enhanced plant tolerance through HM stress-avoidance. We present two conceptual models which illustrate the important compromise between plant growth, plant HM uptake and HM tolerance, and further emphasize the importance of AM symbiosis in buffering the soil environment for plants under such stress conditions.

Heavy metal phytoremediation from a meta-analytical perspective.

We conducted a literature survey and correlated heavy metal (HM) uptake and plant growth factors from published data to estimate the effectiveness of phytoextraction. The indicators of the actual plant HM uptake showed positive correlations with soil-HM concentrations, while the relative plant HM uptake showed negative correlations. Plant growth was negatively correlated with both the plant and soil-HM concentrations.

Effects of AM colonization on "wild tobacco" plants grown in zinc-contaminated soil.

This greenhouse study aimed to determine the effect of colonization by the arbuscular mycorrhizal (AM) fungus (Glomus intraradices Schenck & Smith) on the "wild" tobacco (Nicotiana rustica L. var. Azteca), under soil-zinc (Zn) conditions.

Nitrogen transfer and assimilation between the arbuscular mycorrhizal fungus Glomus intraradices Schenck & Smith and Ri T-DNA roots of Daucus carota L. in an in vitro compartmented system.

Nitrogen metabolism was examined in monoxenic cultures of carrot roots (Daucus carota L.) colonized with the arbuscular mycorrhizal (AM) fungus Glomus intraradices Schenck & Smith. Glutamine synthetase and glutamate dehydrogenase activities were significantly increased in mycorrhizal roots for which only the extraradical mycelium had exclusive access to NH4NO3 in a distinct hyphal compartment inaccessible to the roots.

Maternally-induced modification of progeny phenotypes in the C weed Echinochloa crus-galli: An analysis of seed constituents and performance.

To clarify the physiological basis of maternal inheritance we examined the effect of the thermal environment of mother plants of Echinochloa crus-galli on subsequent seed mass, content and quality. The same plants were grown in a warm and a cold environment until seeds were produced and, since E. crus-galli is a highly inbred species, the observed variation in seed production was a purely plastic response to the environment.