A tomato cell is any cell from a tomato plant, though generally cells from the fruit rather than the roots or leaves are meant. Tomato cells are frequently used in lab classes to introduce biology students to the principles of microscopy and to familiarize them with plant cell anatomy.
Tomato cells are of interest to science because the plants are common and grow easily and the fruit are useful as a model for fleshy fruit from other plants. In fact, tomato cells have been extensively studied in terms of the mechanisms they use to ripen and pigment themselves. Cells are the basic units of any organism, so understanding tomato cells offers key insights to the overall functioning of the plants.