title: Nitric oxide production by the differentiating xylem of Zinnia elegans.
abstract: Nitric oxide (NO) is currently regarded as a signal molecule involved in plant cell differentiation and programmed cell death. Here, we investigated NO production in the differentiating xylem of Zinnia elegans by confocal laser scanning microscopy to answer the question of whether NO is produced during xylem differentiation. Results showed that NO production was mainly located in both phloem and xylem regardless of the cell differentiation status. However, there was evidence for a spatial NO gradient inversely related to the degree of xylem differentiation and a protoplastic NO burst was associated with the single cell layer of pro-differentiating thin-walled xylem cells. Confirmation of these results was obtained using trans-differentiating Z. elegans mesophyll cells. In this system, the scavenging of NO by means of 2-phenyl-4,4,5,5-tetramethyl imidazoline-1-oxyl-3-oxide (PTIO) inhibits tracheary element differentiation but increases cell viability. These results suggest that plant cells, which are just predetermined to irreversibly trans-differentiate in xylem elements, show a burst in NO production, this burst being sustained as long as secondary cell wall synthesis and cell autolysis are in progress.
authors.affiliation: Department of Plant Biology, University of Murcia, E-30100 Murcia, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Gabaldón
authors.forename: Laura V
authors.initials: LV
authors.lastname: Gómez Ros
authors.forename: María A
authors.initials: MA
authors.lastname: Pedreño
authors.forename: A
authors.initials: A
authors.lastname: Ros Barceló
mesh_terms: D017209:Apoptosis / Q000502:physiology; D019659:Asteraceae / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D009569:Nitric Oxide / Q000096:biosynthesis / Q000502:physiology*; D018515:Plant Leaves / Q000502:physiology; D018547:Plant Stems / Q000502:physiology
chemical_list: D009569:Nitric Oxide