A novel approach for detecting molecular O₂ at the subcellular level in plants

What is the typical oxygen status of plant tissues? The answer, perhaps unsurprisingly, is ‘it depends’. A recent meta-analysis revealed that plant tissues may experience oxygen levels ranging from anoxia to hyperoxia exceeding 60 kPa oxygen partial pressure (pO2), depending on tissue type and the environmental conditions under which oxygen status is assessed (Herzog et al., 2023). Most studies included in the analysis employed physical O2 sensors inserted into cells or tissues across various plant organs. Arguably, the insertion of such sensors induces injury, leading some researchers to question whether the resulting measurements accurately reflect the in vivo oxygen status of the investigated cells, tissues, or organs. Excitingly, in an article published in this issue of New Phytologist, Perri, Kahn & Wallabregue led a study (Perri et al., 2025; 247: 2998–3009) in which they introduced a novel fluorescent probe for detecting subcellular oxygen levels, employing two distinct chemical resorufins. Although the technique is still in its early stages, it holds considerable promise for advancing our understanding of subcellular oxygen dynamics in plants.