Two recent studies describe plant root mechanisms. One of them, published in
the journal Molecular Systems Biology, describes the process through which
cells stop growing during cell differentiation; the second one, published in
Journal of Cell Science, describes plant cell replenishment after being
The first study used three hypotheses to explain how cells know when to stop
growing: is it at a certain period after cells got divided, or they detect
the root's position, or cells are able to detect their size. To clarify the
correct hypothesis, Irina Pavelescu, first author of the study, created
three analytical and computational root growth models. The conclusion is
that root cells know when they reached the proper size and stop growing and
start the differentiation. They stop growing due to their size.
The second study discovered more details on root growth and post-damaged
cell repair capacity. The study reports that when root stem cells die due a
genomic stress, a signal of steroid hormones is sent to reservoir stem cells
so that these cells divide and replace the damaged ones. Thus, root growth
is maintained, and so is the plant's life.