From photons to plant defence mechanisms

The natural products of a plant s secondary metabolism have been used in herbal medicine since the beginning of human history. Because the basic function of these chemicals is to protect the plant from attack, it is a logical strategy to investigate and improve the natural resistance of plants and fruit. This, therefore, requires the identification of those components involved in their natural defence response. Thus, modern laser-based techniques, of the type described in this section, are very useful not only as early and sensitive indicators for spoilage, but also to enhance namral resistance of crops. 

One of the most studied plant defence molecules is ethylene (e.g. Morgan and Drew, 1997), a plant hormone that plays an important role in the regulation of many induced processes, such as pathogen infection response, stress resistance, fruit ripening, etc. Although the emission of ethylene exhibits a huge variation among different species, it is well known. 

we will consider several apphcations of laser-analytical methods in the detection and monitoring of plant defence molecules. First, we will outline a laser technique used to study volatile compoiuids such as ethylene. Then, we will focus on new developments of laser-analytical methods for the detection of non-volatile compounds, such as the phytoalexin resveratrol. And finally, as a clear illustration of the applications derived by the use of these laser-based technologies, we will present some methodologies to improve the natural plant resistance by using their own plant defence molecules. 

---