Final answer:
Changes in root shape in plants are primarily due to root growth phases involving the root meristem, elongation, and maturation, as well as radial growth from lateral meristems. Radiation can damage cells and alter growth, but medically it's used in imaging to diagnose internal conditions such as tooth decay.
Step-by-step explanation:
The change in the shape of the root in plants can be attributed to several factors during root growth and anatomy. Roots grow following germination, starting with the emergence of the radicle from the seed which forms the root system. The growth of the root involves different zones including the zone of cell division located at the root tip consisting of actively dividing cells of the root meristem, followed by a zone of elongation where cells lengthen the root, and the zone of maturation and differentiation with root cells specializing into various cell types. This process can be influenced by radial growth through structures called lateral meristems which increase root girth.
In addition, external factors such as gamma and alpha particle radiation can impact root structure by causing cellular damage, likely altering the natural growth process. However, in the context of medical treatments and imaging, radiation affects human tissues such as hair follicles causing hair loss in the treated area, yet it does not cause changes in tooth or root anatomy. Instead, radiation in the form of X-rays can help produce radiographs that detect dental decay or damage within the root or bone not visible to the eye.