ABSTRACT
Growth and morphogenesis of multicellular plant organisms, including land plants and the three classes of macroalgae imply mechanical deformations of the physical structures at the cell and tissue levels. To characterize both these deformations and the mechanical properties of the biomaterial, many kinetic studies of surface deformations on fungal and plant organs have been conducted in the past decades. These studies used natural or artificial surface markers to monitor basic local changes in one or two dimensions of cells or tissues, in response to forces, applied naturally (growth) or artificially (osmotic shocks). However, such studies are scarce in algae, specifically in brown algae, where the complex and diverse morphogenetic processes call for a better description of the cellular and tissue mechanical properties. This chapter provides a protocol to measure the pattern of cell-surface deformations in the filamentous brown alga Ectocarpus sp. using time-lapse video microscopy. To follow the deformations at the subcellular resolution, the filaments were labeled with commercial fluorescent microspheres that permanently stick to the cell surface without disturbing the growth (as much as it can be assessed). This protocol can be used to follow the deformations both during normal growth and during cell inflation/retraction generated by osmotic shocks.
Keywords: Cell shape, cell wall, confocal microscopy, epifluorescence, deformation, mechanical stress, turgor, anisotropy
