Describe what would be seen under a brightfield vs darkfield

Describe what would be seen under a brightfield vs darkfield microscope viewing a onion as the specimen. What are some of the characteristics and descriptions of the onion.

Solution

In case of bright field microscope, it uses direct visible light to magnify the image. These particles now emit a light of longer wavelength, which magnifies the image. The bright field microscope produces image on a bright background. It is generally used in laboratory applications to observe the stained or pigmented specimens. The stained onion specimens appear bright against the unstained regions in the specimen.

The darkfield microscope produces image in a dark background. So that the specimen appears bright on contrast background without staining. This is the most suitable microscope to observe the live specimens (since no staining is needed).

The specimens appear bright against the dark background. Onion root tips are used to observe the different stages of mitosis. When the outer layer of onion bulbs is used, the nucleus is stained by iodine. Without staining, the cytoplasm and plasma membrane are visible.