Plant Stem Cells Perfect Paragraph

The meristems are the stem cell niches in plants, regions of the plant that contain undifferentiated stem cells. These cells are classified as stem cells because they fit the criteria of being self-renewing, undifferentiated, totipotent or pluripotent, and are found in a specialised area called a niche. Both plants and animals have stem cells that can generate new cells. However, plants not only have the ability to regrow entire organs from their stem cells, but can also regenerate themselves from any one of their cells. That is, if the organism were to be dealt cataclysmic damage - such as a tree being cut down to its base - it would be able to regenerate completely. This is due to the fact that all of a plant’s cells, unlike an animal’s cells, are totipotent. When the plant is wounded, the differentiated cells around the wound will dedifferentiate into a group of cells - called a callus - that can grow into any new organ the plant needs. Depending on the concentrations of hormones the callus is exposed to, it will differentiate into different organs. Higher concentrations of auxin lead to more root formation and higher concentrations of cytokinin lead to more shoot formation. From this callus can be grown new organs or even an entirely new plant. Although it is true that all plant cells can be totipotent and self-renewing, they do not fulfill the two other criteria that would make them stem cells, being undifferentiated and being in a niche. Thus, not all plant cells are stem cells, only the undifferentiated cells in the meristems count as stem cells.