The nucleus in a plant cell is typically colorless or appears light-colored under a microscope, depending on the staining technique used. In histological preparations, various stains can be applied to highlight cellular components, including the nucleus.
When using common dyes, such as methylene blue or crystal violet, the nucleus might appear blue or purple. These stains help visualize the nucleus because they bind to the nucleic acids within, allowing for easier observation. However, in its natural state, the nucleus does not have an inherent color, and what we see largely depends on the method of observation and the preparatory techniques used.