Nitric Oxide (NO) Emission from Leaves and Cell Suspensions in Rice (Oryza sativa L.).

Abstract

Recent studies of nitric oxide (NO) in plants have suggested crucial roles of NO in diverse physiological processes, although the pathway of NO production in plants has not been established yet. When rice plants were grown with nitrate, NO emission from leaves was low in air under the dark, but stimulated by light. NO emission in dark strongly increased upon flushing with nitrogen. When rice plants were grown with ammonium, NO emission from leaves was very low in any conditions. In cultured cells grown with nitrate, addition of nitrite to the medium resulted in a rapid NO emission, and that was stimulated in nitrogen. NO emission from the cells grown with amino acids was also enhanced after addition of nitrite in nitrogen, but the steady state level was lower than that of the cells grown with nitrate. Possible pathway of NO production in rice leaves and cells will be discussed.