Cross talk between nitric oxide and growth regulators

Nitric oxide (NO) is a free radical gas formed endogenously in several biological systems, including plants, in which it performs a wide range of functions. Although many aspects of the physiological role of NO in plants remain to be elucidated, evidence is emerging that NO plays an important regulatory role in numerous processes, including stomatal closure, root development, stem elongation, seed germination, the host responses to infection, programmed cell death and senescence. In addition, it is now widely accepted that NO functions as a signal for hormonal responses in plants. Nonetheless, the mechanisms by which NO interacts with growth regulators is still far from clear, although considerable progress has been made during the last decade in our understanding of NO within the entire plant and in plant organelles. Herein, we specifically explore the role of NO and its cross talk with growth regulators in plants.