Fluorescence imaging applied to the study of plant tissues

Abstract

Plant tissues have natural fluorophores on their structure. When plants are exposed to an environmental stress, plant morphology, structural elements and content of fluorophores may vary. Three population of Oryza Sativa (rice) samples grew under control and stress conditions (watered with cadmium 50 μM and 1000 μM solutions). Fluorescence imaging allowed monitoring natural fluorophores such as chlorophylls or lignins in leave tissues. The information from fluorescence imaging was interpreted by the chemometric tool multivariate curve resolution alternating least squares (MCR – ALS) method which provides the pure fluorescence signatures and distribution maps of the fluorophores presents in the plants analyzed. Plants exposed to cadmium were more yellow indicating a lower concentration of chlorophylls. In leaves cross-sections, biological structures seem to be weaker than in non-contaminated plants. The leaf length also decreased in Cd-exposed populations. The fluorescence signatures and distribution maps of three types of chlorophyll and two lignin compounds were resolved. The use of fluorescence imaging techniques combined with chemometric tools are useful to obtain relevant biological, morphological and chemical information about compounds presents in plant tissues.