In this work an improved method is described for using organic solvent extracting to detect nitric oxide. The partition coefficients of the diethylthiocarbamate (DETC)-Fe 2+ complex between different organic solvents and water, the signal intensity of the same NO trapping complex concentration in different organic solvents, and the extracting abilities of the organic solvents were determined. It was found that ethyl acetate was the optimal organic solvent. With ethyl acetate as extracting solvent, the (DETC) 2 -Fe"-NO complex was extracted from water phase to organic phase, and low concentration of nitric oxide in large volume could be detected by electron spin resonance (ESR) at room tem -p e r a t u r e . T h e E S R s i g n a l i n t e n s i t y h a d a g o o d l i n e a r r e l a t i o n s h i p w i t h t h e c o n c e n t r a t i o n o f n i t r i c o x i d e , at a signal-to-noise ratio of 2. The detection threshold of this method was improved to lower than 50 nM, which was more sensitive than the usually used method. The (DETC)z FeZ*-NO complex was stable in the dark at 0-4°C, and there was little change after days. Nitric oxide produced by cardiomyocytes cultured in media and other biological systems was firstly detected with this method.

Recent evidence indicates that nitric oxide (NO) plays an important role in plant hypersensitive cell death. Here, we report that NO treatment led to rapid cell death and induced hydrogen peroxide (H(2)O(2)) accumulation in maize leaves. We also show that NO induced the expression of Zmrboh genes. Pharmacological study suggests that NO-induced cell death is in part mediated via H(2)O(2). In addition, semi-quantitative RT-PCR revealed that NO induced expression of the systemic acquired resistance (SAR) genes, ZmPR1 and ZmPR5.