Hemoglobin as a probe for estimation of nitric oxide emission from plant tissues

a Mechanism of action of MnIP-Cu, a novel probe for detection of NO in plant systems. b Quenching of NO released from seedling roots by exogenous hemoglobin (Hb) in a concentration (Hb)-dependent manner. NO released in solution from seedling roots bathed in varied concentrations of Hb was estimated using NO specific probe MnIP-Cu ex. 330 nm, em. 460 nm. c Conversion of oxyhemoglobin (HbO2) to methemoglobin in the presence of NO. d Absorbance peak for formation of methemoglobin in the presence of NO released from seedling roots in the solution bathed in varying concentrations of hemoglobin (250 μM to 3 mM) separately. e Increase in methemoglobin formation as a consequence of NO release from seedling roots in the bathing solution containing variable concentrations of hemoglobin (Hb). Note: Lower dosage of Hb in solution is insufficient in quenching NO from seedling root