Nitric oxide emission from barley seedlings and detached leaves and roots treated with nitrate and nitrite

Nitric oxide (NO) emission from detached barley leaves, roots and whole plants treated with various nitrate or nitrite concentrations under light/dark and aerobic/anaerobic conditions was quantified by using a chemilumines-cence detector. No emission from detached tissues and whole plants treated with moderate nitrate concentration (60mM) was relatively higher under anaerobic condition, and was positively correlated with nitrite concentration. Darkness and anaerobic condition remarkably induced No emission from detached barley leaves. on the contrary, No emission from detached roots and whole plants was relatively higher in light. As for whole plants treated with 60mM nitrate and 12mM nitrite, the pattern of No emission in normal environment was broken by light-dark and aerobic-anaerobic transition. Light and anaerobic condition induced No emission significantly in the whole plant. The whole barley plant emitted significantly higher amount of No than detached leaves or roots.