| Summary: | Plant growth and developmental processes as well as abiotic and biotic stress adaptations are regulated by small endogenous signalling molecules. Among these, phytohormones such as the gaseous alkene ethylene and reactive oxygen species (ROS) play an important role in mediating numerous specific growth or cell death responses. While apoplastic ROS are generated by plasma membrane-located respiratory burst oxidase homologue proteins, intracellular ROS are produced mainly in electron transfer chains of mitochondria and chloroplasts. Ethylene accumulates in plants due to physical entrapment or by enhanced ethylene biosynthesis. A major crop that must endure high salt and heavy metal concentrations upon flooding in regions of Asia is rice. Ethylene and ROS have been identified as the major signals that mediate salinity, chromium and flooding stress in rice. This mini review focusses i) on what is known about ethylene and ROS level control during these abiotic stresses in rice, ii) on how the two signals mediate growth or death processes and iii) on feedback mechanisms that in turn regulate ethylene and ROS signalling.
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