Enhanced Ni phytoextraction by effectiveness of chemical and biological amendments in sunflower plant grown in Ni-polluted soils

A greenhouse study was conducted as a completely randomised design in a factorial arrangement to assess how inoculation of AMF (arbuscular mycorrhizal fungus) and application of EDTA (ethylenediaminetetracetic acid) as biological and chemical amendments can affect the Ni (nickel) phytoremediation in Ni-polluted soils using sunflower plant. The results showed that the inoculation of AMF increased root colonisation while applying EDTA and high level of Ni decreased it. Microbial incubation has a positive effect on both shoot and root dry yields; however, co-application of Ni and EDTA demoted the growth rate. Shoot nutrients uptake of plants decreased as Ni levels increased. In inoculated plants, shoot uptake of Zn, Fe and Mn was higher in all Ni levels than non-inoculated plants. Ni uptake in plant shoots and roots increased with applying both AMF and EDTA. However, the mean Ni concentration and uptake in inoculated plants along with applying EDTA are higher in sunflower shoots than in roots. As Ni levels increased, Ni extraction and uptake efficiencies increased; it can be concluded co-application of EDTA and AMF was effective in increasing phytoextraction potential of sunflower plants in Ni-contaminated sites. This study highlights that AMF could be suitable for cleaning Ni-polluted areas and it could significantly contribute to phytoremediation technology.     

Floral CO<Subscript>2</Subscript> emission may indicate food abundance to nectar-feeding moths

As part of a study of the roles of the sensory subsystem devoted to CO₂ in the nectar-feeding moth Manduca sexta, we investigated CO₂ release and nectar secretion by flowers of Datura wrightii, a preferred hostplant of Manduca. Datura flowers open at dusk and wilt by the following noon. During the first hours after dusk, when Manduca feeds, the flowers produce considerable amounts of nectar and emit levels of CO₂ that should be detectable by moths nearby. By midnight, however, both nectar secretion and CO₂ release decrease significantly. Because nectar production requires high metabolic activity, high floral CO₂ emission may indicate food abundance to the moths. We suggest that hovering moths could use the florally emitted CO₂ to help them assess the nectar content before attempting to feed in order to improve their foraging efficiency.Electronic Supplementary Material  Supplementary material is available in the online version of this article at