Optical coherence microscopy. A technology for rapid, in vivo, non-destructive visualization of plants and plant cells(1[w])

We describe the development and utilization of a new imaging technology for plant biology, optical coherence microscopy (OCM), which allows true in vi vo visualization of plants and plant cells. This novel technology allows th e direct, in situ (e.g. plants in soil), three-dimensional visualization of cells and events in shoot tissues without causing damage. With OCM we can image cells or groups of cells that are up to 1 mm deep in living tissues, resolving structures less than 5 mu m in size, with a typical collection ti me of 5 to 6 min. OCM measures the inherent light-scattering properties of biological tissues and cells. These optical properties vary and provide end ogenous developmental markers. Singly scattered photons from small (e.g. 5 x 5 x 10 mu m) volume elements (voxels) are collected, assembled, and quant itatively false-colored to form a three-dimensional image. These images can be cropped or sliced in any plane. Adjusting the colors and opacities assi gned to voxels allows us to enhance different features within the tissues a nd cells. We show that light-scattering properties are the greatest in regi ons of the Arabidopsis shoot undergoing developmental processes. In large c ells, high light scattering is produced from nuclei, intermediate light sca tter is produced from cytoplasm, and little if any light scattering origina tes from the vacuole and cell wall. OCM allows the rapid, repetitive, non-d estructive collection of quantitative data about inherent properties of cel ls, so it provides a means of continuously monitoring plants and plant cell s during development and in response to exogenous stimuli.