ABSTRACT
The aim of this study was to investigate the effect of an abiotic factor, i.e., lead at various concentrations (low causing a hormesis effect and causing high toxicity effects), on the generation of signalling molecules in pea (Pisum sativum L. cv. Cysterski) seedlings and then during infestation by the pea aphid (Acyrthosiphon pisum Harris). The second objective was to verify whether the presence of lead in pea seedling organs and induction of signalling pathways dependent on the concentration of this metal trigger defense responses to A. pisum. Therefore, the profile of flavonoids and expression levels of genes encoding enzymes of the flavonoid biosynthesis pathway (phenylalanine ammonialyase and chalcone synthase) were determined. A significant accumulation of total salicylic acid (TSA) and abscisic acid (ABA) was recorded in the roots and leaves of pea seedlings growing on lead-supplemented medium and next during infestation by aphids. Increased generation of these phytohormones strongly enhanced the biosynthesis of flavonoids, including a phytoalexin, pisatin. This research provides insights into the cross-talk between the abiotic (lead) and biotic factor (aphid infestation) on the level of the generation of signalling molecules and their role in the induction of flavonoid biosynthesis.
Subject(s)
Aphids , Flavonoids/metabolism , Lead/pharmacology , Pisum sativum/physiology , Pisum sativum/parasitology , Seedlings/drug effects , Seedlings/metabolism , Signal Transduction/drug effects , Animals , Gene Expression Regulation, Plant/drug effects , Host-Parasite Interactions/drug effects , Host-Parasite Interactions/genetics , Metabolome , Metabolomics/methods , Plant Diseases/parasitology , Plant Leaves/metabolism , Plant Roots/metabolism , Pterocarpans/metabolism , Salicylic Acid/metabolism , Seedlings/growth & developmentABSTRACT
In this work, we present the spectral investigation of the interactions between the coverage with alginic acid (AA) and nanoparticles for three different composites containing 74, 80, and 88wt% of magnetite. These results show that the Fe3O4 nanoparticles are coated with the AA and indicate that there is an interaction between them. Moreover, we have investigated the thermal and magnetic properties of all investigated compounds. We show that bonding of alginic acid to the surface of magnetite results in better thermal stability of the polymer and in higher temperature of AA chains degradation. We find that for dense assembly of magnetite nanoparticles, at low temperatures, the intergranular coupling becomes much stronger than between nanoparticles dispersed in composites.
