Myriophyllum, watermilfoil XS stem water plant. Differential interference contrast (DIC) photomicrograph. Nomarski illumination
Myriophyllum (watermilfoil) is a genus of about 69 species of freshwater aquatic plants, with a cosmopolitan distribution. The centre of diversity for Myriophyllum is Australia with 43 recognized species (37 endemic). Its name comes from Latin, "myrio" meaning "too many to count", and "phyllum", meaning "leaf". These submersed aquatic plants are perhaps most commonly recognized for having elongate stems with air canals and whorled leaves that are finely, pinnately divided, but there are many exceptions. Differential interference contrast (DIC) microscopy, also known as Nomarski Interference Contrast (NIC) or Nomarski microscopy, is an optical microscopy illumination technique used to enhance the contrast in unstained, transparent samples. DIC works on the principle of interferometry to gain information about the optical path length of the sample, to see otherwise invisible features. A relatively complex lighting scheme produces an image with the object appearing black to white on a grey background. This image is similar to that obtained by phase contrast microscopy but without the bright diffraction halo. DIC works by separating a polarized light source into two orthogonally polarized mutually coherent parts which are spatially displaced (sheared) at the sample plane, and recombined before observation. The interference of the two parts at recombination is sensitive to their optical path difference ( the product of refractive index and geometric path length). Adding an adjustable offset phase determining the interference at zero optical path difference in the sample, the contrast is proportional to the path length gradient along the shear direction, giving the appearance of a three-dimensional physical relief corresponding to the variation of optical density of the sample, emphasizing lines and edges though not providing a topographically accurate image.
Size: 5616px × 3744px
Photo credit: © Scenics & Science / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: aquatic, contrast, differential, illumination, interference, microscope, myriophyllum, nomarski, osmosis, photomicrograph., plant., stem, water, watermilfoil, xs
