Development of a Near-infrared Laser-induced Surface Deformation (NIR-LISD) microscope and its application to the dynamic viscoelastic measurements of living plant surfaces at single-cell level

Abstract

We developed a near-infrared laser-induced surface deformation (NIR-LISD) microscope and applied it to the dynamic relaxation measurements of a living plant surface at single-cell level. In the microscope, the surface deformation is induced by a NIR laser beam, then the changes in intensity of probe beam reflected from the surface are measured. The obtained power spectrum reflects the viscoelasticity of the surface. The application of the NIR laser beam in LISD measurements decreased the photo-damages of plant cells, in comparison with the irradiation of a visible laser beam. The NIR-LISD microscope enabled us to discriminate the differences in power spectra between the subapical and lateral regions of tip-growing single rhizoids in Marchantia polymorpha. It has an advantage for the dynamic viscoelastic measurements of cells and tissues that could be damaged caused by the strong absorption to ultraviolet or visible light.