ROS and Phytohormones in Plant-Plant Allelopathic Interaction

Abstract

Allelopathy refers to plant-plant interference mediated mostly by plant released products of secondary metabolism. It was recently suggested that allelochamicals may influence growth of neighboring plants by induction of oxidative stress. We have focused on the role of reactive oxygen species (ROS) and phytohormons (ABA and ethylene) in the biochemical and molecular regulation of plant response to sunflower phytotoxins.

Keywords: ABA; H2O2; allelopathy; ethylene; reactive oxygen species; seed germination.

Figure 1

Schematic of signaling pathways including ROS, ABA and ethylene regulation of germination of mustard seeds imbibed in water or sunflower foliar extract. Sunflower allelochemicals enhanced ROS production, leading to enlargement in membrane deterioration. Declined ACS and ACO activity resulted in decreased ethylene synthesis. Perturbation in hormonal balance: high concentration of ABA and low ethylene evolution made seeds “artificially” dormant. Low energy supply due to suppression in reserve (lipids and proteins) mobilization inhibition ICL - isocitrate lyase and endopeptidase activity) slowed down energy (ATP) generation in the catabolic phase of germination and finally blocked radicle protrusion.