ScienceDaily (Nov. 18, 2009) — Scientists at the John Innes Centre in Norwich, UK, have shown how plants can protect themselves against genetic damage caused by environmental stresses. The growing tips of plant roots and shoots have an in-built mechanism that, if it detects damage to the DNA, causes the cell to 'commit suicide' rather than pass on its defective DNA.

This is a confocal laser scanning micrograph of an Arabidopsis root tip in which the cell outlines are marked in green by a fluorescent protein. The orange region marks stem cells that died after treatment with a drug that damages DNA. (Credit: John Innes Centre)

Plants have, at the very tips of their roots and shoots, small populations of stem cells, through which they are able to grow and produce new tissue throughout the plant's life. These stem cells are the precursors to producing plant tissues and organs. This means that any defect that arises in the stem cell's genetic code will be passed on and persist irreversibly throughout the life of the plant, which may last thousands of years.

It is therefore critical that there are safeguards that prevent stem cell defects becoming fixed, particularly as the stem cells exist at the growing tips of shoots and roots where they are especially exposed to potentially hazardous environments.

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