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A stem is one of two main structural axes of a vascular plant, the other being the root. It supports leaves , flowers and fruits , transports water and dissolved substances between the roots and the shoots in the xylem and phloem , engages in photosynthesis, stores nutrients, and produces new living tissue. [ 1 ]
Stem cell tourism is the part of the medical tourism industry in which patients travel to obtain stem cell procedures. [109] The United States has had an explosion of "stem cell clinics". [110] Stem cell procedures are highly profitable for clinics. The advertising sounds authoritative but the efficacy and safety of the procedures is unproven.
A stem tuber is a thickened part of a rhizome or stolon that has been enlarged for use as a storage organ. [10] In general, a tuber is high in starch, e.g. the potato, which is a modified stolon. The term "tuber" is often used imprecisely and is sometimes applied to plants with rhizomes.
Many organizations in the United States follow the guidelines of the National Science Foundation on what constitutes a STEM field. The NSF uses a broad definition of STEM subjects that includes subjects in the fields of chemistry, computer and information technology science, engineering, geoscience, life sciences, mathematical sciences, physics ...
It follows from the definition that all members of a stem group are extinct. The "stem group" is the most used and most important of the concepts linked to crown groups, as it offers a means to reify and name paraphyletic assemblages of fossils that otherwise do not fit into systematics based on living organisms.
Traditionally, plant stem cells were thought to only exist in SAM and RAM and studies were conducted based on this assumption. However, recent studies have indicated that (pro)cambium also serves as a niche for plant stem cells: "Procambium cells fulfill the criteria for being stem cells since they have the capacity for long-term self renewal and being able to differentiate into one or more ...
A stem cell possesses two properties: . Self-renewal is the ability to go through numerous cycles of cell division while still maintaining its undifferentiated state. Stem cells can replicate several times and can result in the formation of two stem cells, one stem cell more differentiated than the other, or two differentiated cells.
Stem-cell lines are used in research and regenerative medicine. They can be used to study stem-cell biology and early human development. In the field of regenerative medicine, it has been proposed that stem cells be used in cell-based therapies to replace injured or diseased cells and tissues.