Nitric oxide production in tobacco leaf cells: a generalized stress response?

The function of nitric oxide (NO), a gaseous free radical emitted by many plants, is incompletely understood. In the present study the hypothesis that NO generation, like that of the reactive oxygen species, occurs as a general response to different environmental cues was tested. Leaf peels and mesophyll cell suspensions of Nicotiana tabacum cv. Xanthi were loaded with the NO-specific fluorophore, diaminofluorescein, and subjected to an abiotic stressor. Light stress and mechanical injury had no apparent effect on NO production. In contrast, high temperatures, hyperosmotic stress, salinity and epi-illumination in a microscope all led to rapid surges in NO-induced fluorescence. The fluoresce…