Plants and microalgae constantly trigger fast and complex responses to reconcile their internal state with their environment. Microfluidics allows precise control of the flow of media, while modern microscopy techniques allow to image samples at high spatio-temporal resolution. Combination of microfluidics and microscopy allows to observe and characterize the dynamic of plants and microalgae growth and development in control and challenging conditions (a/biotic stresses). The objective of this workshop is to transmit tools to study plants and microalgae behaviors by coupling microscopy and microfluidics. During this workshop, we will demonstrate that microfluidics is a powerful tool to study biological samples at high spatio-temporal resolution. To do so, we propose 2 measurement benches: 1/ Microscopic observations of root behavior (Arabidopsis thaliana) and 2/ hydrodynamic trapping and observation for single cell (microalgae of 5 - 20 µm). Each measurement bench has a dedicated microfluidic chip: a manually closable microfluidic chip to study A. thaliana roots and a hermetically glass bonded microfluidic chip for microalgae. Control of flow will be established using a fully commercial microfluidic system or syringe pumps to demonstrate the versatility of microfluidic systems. The incredible dynamic behavior of plant roots will be demonstrated through real-time microscopic observation of roots growing first in control media then in response to salt stress induced by NaCl. To study microalgae organelle behavior with and without stress (nutritional deficiency), we will take advantage of the autofluorescence of the chlorophyll to locate the chloroplast relative to other stained organelles such as lipid droplets and vacuoles and quantitatively measure their respective number and volume. At the end of this workshop, the participants will be able to prime microfluidic chips, input samples, and observe samples in vivo using time-lapse and/or 3D live cell imaging.