Measurement of Nitric Oxide in Plant Tissue Using Difluorofluorescein and Oxyhemoglobin

Nitric oxide (NO) is now well established as a signalling molecule in plants, regulating various physiological processes ranging from development to responses to pathogens and changes in the physical environment. Various methods for the detection of NO in plant tissue have been described, and all of these methods have serious limitations that impact their utility for accurate detection of NO in plant tissues. Despite such limitations, both difluorofluorescein diacetate and oxyhemoglobin present convenient and relatively easy approaches for measuring NO in plant tissue and their utility can be enhanced by including appropriate controls to address some of the limitations that these two methods have. This chapter provides methods for measuring or detecting NO production in plant tissue using either difluorofluorescein diacetate or oxyhemoglobin.