A Method for Imaging Oxygen Distribution and Respiration at a Microscopic Level of Resolution

Conventional oxygen (micro-) sensors assess oxygen concentration within a particular region or across a transect of tissue, but provide no information regarding its bidimensional distribution. Here, a novel imaging technology is presented, in which an optical sensor foil (i.e., the planar optode) is attached to the surface of the sample. The sensor converts a fluorescent signal into an oxygen value. Since each single image captures an entire area of the sample surface, the system is able to deduce the distribution of oxygen at a resolution level of few micrometers. It can be deployed to dynamically monitor oxygen consumption, thereby providing a detailed respiration map at close to cellular resolution. Here, we demonstrate the application of the imaging tool to developing plant seeds; the protocol is explained step by step and some potential pitfalls are discussed.