Nitric oxide affecting root growth, lignification and related enzymes in soybean seedlings

Abstract

This study analyzed the involvement of nitric oxide (NO) in the root lignification of soybean seedlings. To this end, changes in root cell viability; phenylalanine ammonia-lyase (PAL) and soluble and cell wall bound peroxidase (POD) activities and lignin and hydrogen peroxide (H 2 O 2 ) contents of soybean roots treated with the NO-donor sodium nitroprusside (SNP) and its relationships with root growth were evaluated. Seedlings were cultivated in a nutrient solution supplemented with 5 to 1,000 lM SNP for 24 h. At an extremely low concentration (5 lM), SNP induced root growth and increased lignification and activities of related enzymes (PAL and cell wall-bound POD). At a high concentration (1,000 lM), SNP reduced root growth and lignification (PAL activity and H 2 O 2 and lignin contents) and caused a loss of cell viability. Application of potassium ferrocyanide (an analog of SNP that cannot release NO) and PTIO (2-phenyl-4,4,5,5,-tetramethylimidazoleline-1-oxyl-3-oxide, a scavenger of NO) revealed that the inhibitory/stimulatory effects on root lignification may be due to NO itself. These results indicate that NO, depending on its concentration, may act as a stress factor, due to its toxic action, or as a signal molecule, inducing soybean root growth and lignification.

Nitric oxide effect on root architecture development in Malus seedlings

“…The color of LRs in 10 µmol and 50 µmol SNP treated seedlings was white, while that of 100 µmol and 500 µmol SNP treated seedlings was brownish yellow and brown, respectively. These results indicate that apart from a signaling molecule, exogenous NO may act as a stress factor in controlling LR initiation and development, in agreement with recent findings in soybean seedlings (Böhm et al 2010).…”

Effect of nitric oxide treatment on antioxidant responses and psbA gene expression in two wheat cultivars during grain filling stage under drought stress and rewatering

“…It has also been evident that the effect of NO is in concentration-dependent manner. In soybean seedlings, a high concentration (1 mM) of SNP reduced reversely root growth and lignifications, and caused a loss of cell viability as a result (Böhm et al 2010). In wheat plants, as suggested by others research, high concentration of SNP (2 mM) inhibited wheat growth, aggravated the accumulation of hydrogen peroxide and lipid peroxidation, and even was considered as another stress factor (Tian and Lei 2006).…”

“…Many previous studies have reported presence of NO in the plant kingdom and its involvement in growth, development, and defense responses (Böhm et al 2010;Beligni and Lamattina 1999). Exogenous NO donor could ameliorate the inhibition of wheat seed germination induced by drought stress (Liu et al 2010).…”

DNA Methylation Changes Induced in Rice by Exposure to High Concentrations of the Nitric Oxide Modulator, Sodium Nitroprusside

“…More specifically, NO plays important role in responses to abiotic stresses (including wounding, oxidative damage, heavy metal toxicity, drought, and salinity) as well as biotic stresses (Arasimowicz-Jelonek and FloryszakWieczorek 2007;Qiao and Fan 2008;Misra et al 2011;Siddiqui et al 2011). Depending on the concentration and site of action, NO could serve either as a cytoprotectant or a cytotoxin (Beligni and Lamattina 1999;Lamattina et al 2003;Böhm et al 2010). To date, several reports have signified cytoprotective roles of NO at low concentrations in promoting normal plant growth and development (Beligni and Lamattina 2001;Libourel et al 2006;Bethke et al 2007).…”