From Cell Division to Organ Shape: Nitric Oxide Is Involved in Auxin-Mediated Root Development - Communication in Plants: Neuronal Aspects of Plant Life - page 128

Fig. 9.2. NO modulates root architecture. Photographs of tomato seedlings incu-
bated in water ( control ), 1 mM of the NO scavenger 2-(4-carboxyphenyl)-4, 4,5,5-
tetramethylimidazoline-1-oxyl-3-oxide, potassium salt ( -NO ) and 200 µM of the NO donor
sodium nitroprusside ( +NO )for5days. Bar :1cm. Insets Representative photographs of
fullyelongatedprimaryrootcells. Bar :50µm
showed that the NO-dependent reduction in primary root length correlates
with an inhibition in root cell elongation (Fig. 9.2, inset).
LRsoriginatefromazonedistaltotheactivelydividingprimaryroot
meristem. Hence, during the initiation of LRs, pericycle cells must dedif-
ferentiate and reenter the cell cycle. The plant hormone auxin promotes
theG1-to-Sphasetransitionthroughtheexpressionofcellcycleregulatory
genes like cyclins and cyclin-dependent kinases (CDK) in some pericycle